Mercury Cougar Problems

Plastic Intake Manifold May Crack Causing Coolant Leak on Mercury Cougar

Problem Description and Possible Solution

The Mercury Cougar 4.6L V8 with a 100% plastic intake manifold is known for engine overheating, even with normal use, and a coolant leak from the front of the manifold. This will often trigger the check engine light and low engine coolant warning light.

The engine coolant leak is from a factory defect, which causes cracking on the front coolant passage of the intake manifold. In a very short time, this leak will lead to engine overheating issues, especially while the vehicle is idling.   

Between 1999 and 2001, Ford released an updated version of this engine, known as the 'PI' version with a metal coolant passage on the front of the intake manifold, to prevent future issues.

There is no factory authorized repair for the intake manifold, and replacement is required to correct the engine coolant leak and overheating issues.


(10 people reported this problem)

Mercury Cougar Vehicles With This Problem

RepairPal Verified
Average mileage: 110,315 (50,000–194,000)
Engines affected: 3.8L V6, 4.6L V8
2 model years affected: 1997, 2000
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Viewing 1-6 of 6 comments
Just found out today that my 97' Mercury Cougar has a cracked intake. Will cost between $500-$600 to fix and has a bad oil leak also. Pretty expensive for an old car with a lot of miles. But then again it went 194,000 miles before it did it so maybe that's a good thing. Still there really should have been a recall on something that's plastic. Still a nice ride so I'm sure I will have it fixed.
Didn't know about the class action lawsuit or anything. I never had any external antifreeze leaks, but a recurrent leak of some sort developed on the floor of the passenger side. Low coolant indicator light came on every couple of months, so I added more accordingly. Took to a mechanic when a rattling sound developed under the hood, and was told I needed to get rid of the car, due to cracked plastic manifold gasket. Barely made it to a lot to trade it in, and antifreeze leaked out all over their pavement.
1997 Mercury Cougar - replaced thermostat still overheating - leaking anti-freeze but not sure where
engine overheated, took to shop and when tech pressure tested system, it was leaking around the heater hose area where it comes out of the minifold