Ford Crown Victoria Intake Manifold Replacement Pictures

For today's project, we're going to replace the air intake manifold on a 1998 ford crown victoria police interceptor because it is cracked and leaks antifreeze.

One day driving on the highway, I heard a hissing sound from under the hood while accelerating hard up a steep incline grade. A little while later, a slight odor of antifreeze was present. When the car was stopped and the hood opened, bright green antifreeze was in places it shouldn't be like in the fuel injector well, on the back of the alternator, and the engine valley. Below are a couple pictures taken shortly after this drive.

A closeup of the injector well

A closeup of the green colored alternator bracket bolt

Interestingly, the intake manifold didn't leak visibly when the engine was idling in the driveway. There was definetly a leak somewhere when the system was under high pressure though.

So it's part's acquisition time. Here's our replacement intake manifold, part of the aftermarket dorman 138004 kit.

The universal alternator bracket and the two thermostat bolt spacers

The thermostat and o-ring seal

Here are the self tapping bolts that were included to hold down the ignition coils and throttle cable bracket. The oem ford unit used machine screws with brass inserts in the intake manifold instead.

The part number from the box. Do note that this is an early revision of the dorman intake manifold kit purchased within a few months of when dorman first offered this kit in 2005. The intake manifold kit currently offered by dorman for the 96-00 crownvics has a part # of 615-178.

Dorman: 1380004
Hollander: 329-1514
Ford: F8AZ-9424-CA

Now that the needed parts have been acquired, the installation can begin.

The first step is to disconnect the negative terminal of the battery to prevent damage to electrical harnesses or electrical fires during our project.

Disconnect accelerator linkage

Remove alternator, cruise control cable, a couple vacuum harnesses, air intake zip tube and various bracketry.

Remove the remains of windshield wiper cowl

Remove throttle body and air intake plenum

Start disconnecting various electrical harnesses

Deal with the crash bracket that protects the rear portion of the driver's side fuel rail

Now that the crash bracket is out of the way, the fuel rail can be removed

Now remove the ignition coils and the intake manifold itself

Here's the intake valley with the manifold removed but gaskets still present. That black metal tube running through the middle of the valley returns engine coolant from the heater core to the back of the water pump.

The EGR valve->Tube Nut was stubborn in this case, so the nut was left installed and the valve removed from the plenum instead.

The sensor with the white connector mounted in the aluminum casting on the driver's side cylinder head is for the fail safe cooling. This sensor is installed directly into the aluminum casting and does not directly touch engine coolant or oil, instead it monitors the raw temperature of the aluminum head casting. This is a new feature for the 1998 model year, 1997 and prior crownvics will not have this sensor.

Time for a work break, so the hood is closed.

Notice how much space there is in between the windshield and hood without the windshield wiper cowl installed?

Here's the crash bracket and it's mounting fasteners removed from the car. Note that this bracket will not be present in 1997 and earlier crownvics.

There was a possibility of some rain overnight, so the cylinder head ports were covered using some saran wrap from the kitchen which was weighted down with the ignition coils and some rags.

The covering turned out to be an unneeded precaution in this case, but it would have been a bad thing if lots of water poured into the engine from an overnight rain.

Lets take a look at the old oem ford intake manifold next to to the aftermarket dorman one. Later oem ford units have the aluminum front coolant crossover too, but this oem ford unit is an early service unit manufactured in 2000.

Notice the integrated throttle body gasket on the dorman unit?

Also note that there are no brass inserts to hold the ignition coils down. Self tapping sheet metal screws are used instead. Not a big deal as these fasteners are essentially under no load and you probably wouldn't run into any problems running your crownvic without any ignition coil fasteners at all.

The dorman intake manifold has the intake manifold->cylinder head bolt torque sequence cast directly into the plastic. There are also a couple rectangular openings besides where throttle body mounts that open directly into the intake valley below.

Here's a closeup of the heater hose connection port. The oem ford unit uses a brass insert.

The dorman unit is a plastic resin heater core connection port instead. Be careful not to over torque the hose clamps to prevent damage. Do note that some oem ford crownvic intake manifolds also use a plastic resin heater connection tube too.

Here's the other side of the intake manifolds that would normally be connected to the cylinder head ports

Notice the integrated orange and blue colored gaskets on the dorman intake manifold?

Blue Gasket = Coolant Passage
Orange Gasket = Air Passage

Here's a closeup of where the aluminum coolant crossover meets that nylon resin portion of the intake manifold.

There appears to be a common misconception among the general public that the front coolant crossover on their crownvic is solid metal from one cylinder head connection point to the other. This is definetly not the case with either the aftermarket dorman intake manifold or the later oem ford intake manifold that has the aluminum front crossover. There is a peice of plastic wedged in between the head connection surface on both intakes.

Here's a closeup of the other side of the intake where the thermostat would normally be mounted. Do note that the waterneck bolt holes in the intake manifold are unthreaded and the really long coolant gooseneck bolts thread into the cylinder head below.

Around the time that I was replacing the intake manifold on this car, there were a bunch of failures of the under intake manifold hose reported on crown victoria internet discussion forums. Since I did not find it desirable to have to remove the newly installed dorman intake manifold anytime soon, I also elected to replace under intake heater core return too.

Also back in 2005, replacement gaskets were not avaliable for the dorman intake manifold. If you wanted new gaskets, you needed to purchase a new intake manifold kit. It's now 2010 and the dorman intake manifold gaskets are avaliable aftermarket and parts avaliablity is no longer a concern.

Two replacement o-rings were also needed

F8AZ-18B402-BA

W704593-S100

The old heater core return tube was difficult to remove. It did not simply slide off the waterpump nipple like the shop manual implied. I ended up cutting the old return tube with a hacksaw and the spinning the tube off with a pair of visegrip pliers instead.

Here's the return tube nipple after being cleaned up with some 600 grit sand paper and having the two new o-rings installed

Here's the empty intake valley. If this hose develops a leak, coolant will flow out the hole in the rear which then will drip down through the transmission bellhousing area. Many mechanics that aren't familar with crownvics will misdiagnose a leaky under intake hose as failed freeze core plugs.

Before intalling the new heater core return tube, lubricate the o-ring seals with some antifreeze

The cylinder head sealing surfaces will need to be cleaned up some before the new intake manifold can be installed. For this task, some carburetor cleaner and razor blades worked well for getting those stubborn carbon desposits and other grime removed. While the razor blades were out, the remnants of the old egr gasket were also cleaned off the egr valve and intake plenum.

Here's a test fit of the new intake manifold. Note, coolant temperature sensors have been loosely installed. And many mounting fasteners are inserted finger tight to ensure that all mounting fasteners will be installed in their proper locations

Here's a closeup picture of the failsafe cooling sensor that was mentioned earlier

Here's our project car after sitting outside for the night

Here are the really long thermostat bolts. These pass through the intake manifold and thread into the cylinder head below. The intake manifold does not contain any threads for these bolts to thread into, instead the intake manifold is wedged in between the bolt heads and the cylinder head below.

For removing these bolts, a pneumatic air impact wrench with the pressure regulator set really low works good. If you encounter stubborn bolts don't just stick a long breaker bar and push with all your muscles. You are likely to snap the bolt in two with this method and then have the frustrating task of removing the broken bolt remnants.

Instead of replacing the waterneck gooseneck like the oem ford kit does, the aftermarket dorman kit contains two aluminum spacers.

Here are the two really long thermostat gooseneck bolts sitting on top of the intake manifold for size comparison.

I removed both heater core hoses since both the intake manifold and under intake heater core tube were being replaced

Here is the throttle cable bracket next to the oem machine screw & aftermarket dorman self tapping bolts

The fuel rail, air intake plenum, and ignition coils reinstalled

A closeup picture of the fuel rail flex hose spring locks. Do note that in 1996-1997 crownvics, the fuel rail flex hoses are located on the driver's side of the car instead of the passenger's side.

Here's the oem alternator bracket next to the aftermarket dorman one

The air intake zip tube, airbox lid, alternator, and most of the remaining components have now been installed. My car's engine will be ready to run after the battery is reconnected

Windshield wipers would be a nice addition to my ride though

Now that the car is in running condition again, let's take a closer look at the old intake manifold that failed

This is a closeup picture of the area on the front of the intake manifold that leaked coolant. If you look closely, you can see a thin white line where the crack is located.

Here's a closeup of the area where the heater core hose would connect. This area also had an intermittent leak when the coolant system was under high pressure. This leak caused coolant to squirt out which would then collect in the #4 spark plug well and short out the #4 ignition coil causing a bad misfire.

Although there were a handful of problems with this manifold, the brass heater hose insert still sealed good to the intake manifold.

Here is a closeup picture of the area where the thermostat would be located. Although this area wasn't leaking coolant yet, there are some cracks starting to develop in this area.

Here's the intake manifold from the top

On the front coolant passage are two metal inserts for mounting coolant temperature sensors. The insert on the right near the thermostat area started to spin in the plastic casting when the plug was removed.

A look at heater core return tubes from other model year crownvics. The 1992-1995 & 1996-1997 return tube assemblies

A closeup of the flex hose sections of the return tubes. If the metal portion of the tube is in good condition, you can cut off the metal crimp and install regular heater hose with a worm drive clamp here.

The other end of the tube assembly where the heater core hose would connect and the dpfe sensor be mounted.

Here's a 1996 ford crown victoria police interceptor with the intake manifold removed to replace a leaking under intake manifold hose

Previous patches had been attempted with the intake still installed on the car, but they didn't stop the leaks

So a new return tube was installed

The solid metal return tube used in the 1998-2000 crownvics. You can install this tube into a 1996-1997 crownvic if you remove the waterpump, pound out the old heater core tube, and install a 1998+ waterpump tube. But in most instances, you'll probably want to stay with the original style tube that your car came with.

PI vs NPI intake ports

Starting in the 2001 model year, crown victorias recieved PI "Performance Improved" ports on the intake manifold and cylinder head. These flow a little better than the NPI "Teardrop" ports used in the 2000 and earlier crownvics. Do note the acronyms used here:
PI = "Performance Improved"
NPI = "Non- Performance Improved"

PI does NOT equate to police interceptor in this context.

On the left is a PI inake manifold for 01-02 crownvics. On the right is an NPI intake manifold for 96-00 crownvics.

Here is a closeup of the NPI teardrop ports that you'll find on 96-00 crownvics

And a closeup of the PI ports that you'll find on 2001 and later crownvics.

On the left is a cylinder head from an NPI engine. On the right is one from a PI engine.

Some crownvic owners have found that they can use a 2001+ intake manifold on their 1996-2000 vehicles if they swap in the later style heater core return tube and apply some rtv around the seal port surfaces. This is reported to increase airflow & horsepower to some extent. But be warned that some crownvic owners have ended up with difficult to diagnose driveability problems after this swap too.

2005 Crown Victoria Intake Swap Pictures

Below are some pictures taken by DetroitP71 on www.crownvic.net during an intake manifold project on his 2005 crown victoria police interceptor.

Here is the intake manifold valley. There are some differences to note in the valley versus the 1998 police interceptor pictured above:
-The heater core return tube runs towards the driver's side of the valley instead of through the center
-The intake manifold ports are PI rather than NPI teardrop
-The engine has a knock sensor located in the center engine valley.

A closeup of the knock sensor which was added starting in the 2003 model year. This allows the pcm to advance the ignition timing further for more horsepower without the engine pinging/knocking.

A closeup of the heater core return tube curvature near the waterpump

The new intake manifold installed

This 2005 crownvic has the same cursed crash bracket setup as the 1998 crownvic pictured above.

The new intake manifold in it's shipping box

Starting in the ??2003?? model year, a foam insulator was introduced to lower engine noise. You don't really need this part, and can discard it if desired.

One issue that I noticed shortly after installing the dorman intake manifold kit was that the upper radiator hose ran really close to the alternator bracket near the waterneck gooseneck.

The oem ford intake manifold kit contains a new waterneck that angles the hose differently and a revised upper radiator hose so that this problem would not be encountered.

This particular waterneck appears to have been used only on 1998 model year crownvics, and if you have a 1996-1997 or 1999-2000 crownvic you probably won't encounter this clearance issue with the dorman intake manifold kit.

Here's a 2000 crownvic with a different waterneck for comparison

Notes:

The 1996 and later crown victorias have an intake manifold constructed of a nylon resin with hot engine coolant flowing through it. Intake manifolds on these cars are wear items that often have to be replaced during the effective life of the vehicle.

If you purchased a "pre-owned" 1996-2000 police cruiser from auction, there is a good chance that your intake manifold has already been replaced. In severe police duty with lots of idling and high throttle application, intake manifolds often didn't make it to 50k miles before they sprung a leak on the front coolant crossover or near the passenger's rear heater hose connection point.

There was a customer satisfaction program for 1996-2000 police cruiser owners to have their intake manifolds replaced for free at their local ford dealership if they expierenced coolant leaks and the vehicle was less than 7 years old. But this program has long since expired because all the affected vehicles are now over 7 years old.

Here are a collection of documents that ford issued about the 01M02 program:

http://www.p71interceptor.com/intakemanifold/01m02

There is also a parts update avaliable which includes a listing of the parts inside each individual intake manifold kit:

http://www.p71interceptor.com/intakemanifold/01m02/tsb0222.html

And here is a collection of alternator & alternator bracket part numbers:

http://www.p71interceptor.com/alternator/modelnumbers

Do note that the 01M02 customer satisfaction program does NOT apply to 2002 or later vehicles. And you will have to pay out of your own pocket for this repair unless your crownvic is new enough and has low enough mileage to still be covered under the ford factory powertrain warranty.

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The 1992-1995 crown victorias used a solid aluminum intake manifold. Though the manifold itself is contructed of solid metal rather than a plastic resin, these cars still sometimes encounter intake manifold related problems:

-The aluminum intake manifolds tend to collect combustion debris internally clogging up the EGR passages. This problem is essentially unheard of on the later cars with the plastic intake manifolds.
-The aluminum corrodes around where intake manifold connects to the cylinder head coolant passages. If corrosion is bad enough, you'll have external leaks.
-The gaskets in between the intake manifold and cylinder heads can "dry up" and start to leak. Most of the later cars will have had their intake manifolds replaced by now, and will have had new gaskets installed as part of the intake manifold replacement procedure.
-The heater core return hose which runs underneath the intake manifold has a rubber section that attaches to the back of the waterpump. The rubber changes texture as it gets older, and it's not uncommon on a 15+ year old crownvic to find your intake valley full of engine coolant from a leak in this part. Many technicians will misdiagnose a leaky under-intake-manifold-hose as bad freeze core plugs. And to repair this hose, you have to remove the intake manifold. 1998+ crownvics have a solid metal coolant return tube under the intake manifold that rarely fails even in the "rust belt".

Also note that downgrading a later car to the early solid aluminum intake manifold is not really a viable solution:

-The throttle body is turned at a different angle
-The egr system hardware is different
-Wiring harnesses are different lengths to accomadate the different component layout.
-Many parts for the 1992-1995 cars such as accelerator cables are obsolete and no longer avaliable as service parts from ford.
-The 2001+ cars have performance improved (PI) heads with different shaped ports on the cylinder heads than the 1992-2000 cars did.

For performance minded individuals, also note that the early 1992-1995 intake manifolds are somewhat restricted in airflow compared to the later units. This will lower engine horsepower & torque to some extent.

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In the aftermarket, dorman/motormite sells an intake manifold kit for the crown victoria/grand marquis/lincoln towncar. This kit is considerably less expensive to purchase than the oem ford kit from your local ford dealership. Although not an exact replica of the oem part, the intake manfold kit seems to have good durability in the field. If you order an intake manifold from autozone, advance auto, pepboys, etc you're getting the aftermarket dorman/motormite intake manifold kit.

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If you read through internet crown victoria message forums, you'll encounter some people saying that replacing the intake manifold on their car is really easy. Yet you'll find other people claiming that their car never ran properly after they attempted to replaced their own intake manifold. Here are a few tips about this project:

-Do not use pneumatic air impact wrench to TIGHTEN any of the bolts. Use only manual hand tools instead. This will take a little bit extra time, but considerably lower your chances of stripping out the threads in the aluminum cylinder heads.

-Use a torque wrench to ensure that the bolts are tightened to the proper specifications.

-Follow the sequence listed in the factory shop manual for the final tightening sequence for the intake manifold->cylinder head bolts.

-You will likely have problems removing the two really long bolts which hold the upper radiator hose gooseneck to the intake manifold. A pneumatic air impact wrench with the pressure regulator set really low can usually break these bolts free without snapping them. If you stick a socket with a really long breaker bar on these bolts, it's likely that you'll snap the bolt in half. Removing the broken bolt remnants will be a big project because these bolts are threaded directly into the cylinder head underneath the intake manifold.

-1998 and later cars have a factory installed "crash bracket" covering the rear of the driver's side fuel rail. You need to remove this bracket before the intake manifold will come out of the car. You will find this bracket easier to remove if you pull out the windshield wiper housing first.

-Carefully note where each wiring & vacuum harness goes before removing them. Take pictures with your camera if you are not familar with these cars.

-The egr valve often doesn't want to seperate from the tube which connects to the exhaust manifold. This is not usually a problem because the bolts which hold the egr valve to the intake plenum usually seem to turn freely. You will need a new egr valve gasket if you elect to use this method though.

-If you are in a professional repair shop enviroment, there is an alternative to removing the egr valve from the plenum. Use an oxy-acetylene torch to heat the egr tube nut until it's a dull red color. The egr tube nut should then spin freely while everything is still hot. Wear gloves with thermal insulation and be careful not to injure yourself during this task though.

-If you have back problems, you'll probably want to take your car to a repair shop for this repair. During the intake manifold swap, you'll be standing with your back bent over your car's fenders for a few hours.

-If you're working outside, look at the weather forecast before beginning the project. You will have the intake manifold ports open directly to the atmosphere. If it starts to rain really heavy during the project, you could get lots of water inside your engine.

-It would be a good idea to purchase a new set of heater core hoses before beginning this project. After rubber hoses have been installed for several years, they often won't seal properly when they are reinstalled onto the new intake manifold.

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When purchasing an intake manifold from your local ford dealership, the parts counter consultant may ask whether you have a 4G or a 6G alternator in your 1998-2000 crownvic. Here are some pictures of the two different alternators side by side for visual comparison.

http://www.p71interceptor.com/alternator/convert4g6g

Note that the aftermarket dorman/motormite intake manifold kit contains a universal alternator bracket which fits both 4G and 6G alternators.

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in the 1992-1997 crownvics, some taxicab companies devised a quick & dirty hack to fix leaking under intake manifold heater core return hoses.

first they would remove the old leaking heater core hose from the waterpump nipple. then they would install generic heater core flex hose onto the waterpump nipple and run the hose outside the engine valley to the tube on the heater core near the firewall. this solution was functional, but didn't look very nice.

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Part Numbers

Under Intake Manifold Heater Core Return Tubes
1992-1995 F1AZ-18B402-AF (supercedes F1AZ-18B402-A)
1996-1997 F6AZ-18B402-AC
1998-2000 F8AZ-18B402-BA (o-rings are W704593-S100)
2001-2002 1W7Z-18663-AA
2003-2009 3W7Z-18663-BA (to 04/06/2009)
2009-2010 9W7Z-18663-A (from 04/06/2009)

Water Pump->Heater Core Return Nipples
1992-1997 F1VY-8555-A (waterpump -> under intake tube)
1998-2010 F75Z-8555-AA (waterpump -> under intake hose tube. includes two W704593-S100 o-rings)
"water bypass tube"
"pi coolant nipple"

Water Pump O-ring - F1VY-8507-A

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Ford oem intake manifold kits (Part Numbers current as of 02/08/2010)

1996-1997 F8AZ-9424-AAA (Kit to replace plastic intake)
1999-2000 F8AZ-9424-BAA (4G Civilian Alternator "Straight Fins In Case") (1998 civilian crownvics have 6G alternator use F8AZ-9424-CA kit)
1998-2000 F8AZ-9424-CA    (6G Police Alternator "Curved Fins In Case")
1996-2000 F8AZ-9424-CB   (Bare intake. No other parts included. Used to replace service intake manifold with aluminum cross over.)
2001-2002 1W7Z-9424-AAA (4G Civilian Alternator)
2001-2002 1W7Z-9424-BA (6G Police Alternator)
2003-2005 3W7Z-9424-AE
2006-2009 6W7Z-9424-AA (From 06/19/2006 to 07/21/2008)
2009-2010 9W7Z-9424-A    (From 07/21/2008)

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Thermostat Parts
1996-2006 N811011-S309 Thermostat gooseneck bolt
2007-2010 W704693-S437 Thermostat gooseneck bolt M8x95mm
1992-2010 F1VY-8255-A Thermostat gasket (RG-571)

1992-1995 F1VY-8592-AA Gooseneck
1996-2000 F6AZ-8592-AB Gooseneck
1998-1998 F6ZZ-8592-C   Gooseneck
2001-2008 1W7Z-8592-AB Gooseneck (To 12/03/2007)
2008-2010 9L3Z-8592-B Gooseneck (From 01/02/08)

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Suggested article revisions from DetroitP71

1. Include torque values, if you don't have them, I do and they are also listed in the BOK "common torque values" you could include a link to this post.
2. Include Intake manifold torque sequence order. This order is not the same for all years. I don't know where the change happend, maybe NPI to PI? I have a picture posted that shows both side to side. IMO it is related to the crash bracket introduction.
3. This is a good time to replace the injector O-rings. I should have pictures for that. O-rings are not cheap though and you will need two bags. Fuel-rail in my case did not have to be removed I just moved it to the side.
Same for plugs, they should at least be checked. The leaking coolant could have caused some missfires, it did on mine, I even had a bad COP that I replaced a week or so later.
4. Not sure if you want to include this but I would not suggest using a Dorman for PI replacements. There is a very cheap source; Fordracingparts.com (less them 50% of dealer pricing) or ADTR. Or get a Ford OEM part from TascaParts.com, still a lot cheaper then the dealer.
5. There are issues with the brass heater hose insert leakage. There is a picture on CVN that shows a ceative fix for this. If you want it I can look it up.
6. Good point of taken the wiper tray out (good time to clean it out) have you seen what I found in there? But if you are working outside, like you pointed out this can be a risk. How about just covering up the hood of the car with a tarp or a partial tarp. Rain is one thing but I had to deal with snow that then accumulates and freezes.
7. When people work on this they might be inclined to clean the plenum and Throttle body inside. The Trottle body and throttle valve should not be cleaned sice they are coated. However EGR passages should be inspected and cleaned.

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Closeup pictures of a crownvic intake plenum, egr valve, egr tube and exhaust manifolds are avaliable on this webpage.

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Question & Answer

Can I print out this document?

Yes, printing is allowed. Digital Rights Management (DRM) is not implemented on this particular webpage. But do note that you will need close to a hundred sheets of paper to print a complete copy of this document.

Is this document intended to replace the ford shop manual procedure for intake manifold installation?

No. This document is intended to be a supplement to the ford shop manual.

Why are acronyms like EGR, zip tube, and other words that I don't understand used in this document?

This webpage is constructed with the assumption that the reader has lots of background knowledge in automotive technology. Being an automotive service technician is a highly skilled trade despite the low salaries and long work hours that people in this field often encounter. It should be noted that there are numerous websites that teach a basic understanding of car mechanics. Some specialty sites like www.crownvic.net will cater specifically to your crownvic too.

How many miles can I expect to get out of my intake manifold before it fails?

Unknown. This depends on a variety of factors including:
-Heat Load (i.e. Phoenix, Arizona versus Bangor, Maine)
-Engine Idle Time
-Mileage
-Driving Style (Young male teenager driving with many hard wide open throttle runs versus an older grandmother driving and never getting over 3000 RPM)
-Number of cold starts (The engine goes through an expanision/contraction cycle every time it is started/stopped)
-Revision of the intake manifold (Ford has released several different intake manifolds for these cars)
-A randomness factor

Do the intake manifolds with the aluminum crossover ever fail?

Yes. Failure point include:
-the nylon resin in the area that the heater core hose connects
-the nylon resin that's wedged in between the aluminum crossover and the aluminum cylinder heads
-the o-rings which seal the aluminum crossover to the nylon resin underneath

Should I purchase a "pre-owned" intake manifold from a salvage yard?

No. This is not a recommended practice. But if funding is really limited, this could be a temporary fix to get your broken car back on the road for a little while.

How much will my local ford dealer charge to install a new intake manifold on my car?

Ford has a handful of different crownvic intake manifold kits avaliable, but most of these cost somewhere around $500. So with a few hours labor, figure around $1,000 for this repair. Having the aftermarket dorman intake manifold kit installed at an aftermarket repair shop may be a little cheaper. But you increase your risk of unforseen problems by using an aftermarket repair shop because some of the technicians at these shops have never installed a crownvic intake manifold before.

Are there cars with more severe intake manifold problems than the crownvic?

Yes. Some owners of vehicles with the general motors 3800 engines have expierenced hydrolocked engines after intake manifold failure. In those cars, hot egr gasses fatigue the intake manifold which allows liquid coolant to flow into the air intake ports. On the crownvic, intake manifold failure causes an external leak by contrast.

Can I stop an intake manifold leak by using a $3.99 can of coolant stop leak product from pepboys?

No. This solution is not likely to be effective. But you do run the risk of overheating your engine with this solution. Click here to view some pictures of a radiator that's really plugged up from lots of stop leak product being installed.