Chasing a coolant leak

SWFLGT

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Yesterday on the way home I smelled coolant burning, it seemed to be originating from around the thermostat housing somewhere. It seems to be spraying onto the hood and across the engine bay.
I could not visibly see a leak or any kind of spray going on.

Today I replaced the thermostat and o-ring since I had it handy, buttoned her back up and went for a spin. Got back home and still the same thing. I can not visibly see any place leaking, but it is coming from somewhere. I tried to rev the engine a bit to see if I could see where it's coming from but I can't find anything. It seems to only leak under hard acceleration.

Any ideas? Is this the intake manifold possibly? It's a 98 NPI engine.
 

DeepList

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Coolant can be blown around in the wind while you drive and end up pretty much anywhere. Some common places to check would be around the thermostat housing, like you've already done. Also, check the lines that go to the heater core and the weep hole on your water pump. Do you have access to a pressure tester? Under about 20 psi, the source of the leak will be obvious.
 

Musturd

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Bingo get a pressure tester . You'll find it easily around 20-24psi
 

Leo 5.0

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Just a thought, regardless if it applies, something to check.
My 02 did something very similar, I didn't find it til it blew. I didn't have a leak anywhere, but a constant coolant smell.
I figured no leak no issue. Drove it til one day coolant went everywhere and my heads warped.

Check the back of the intake on the passenger side.
Where the hose connects to the intake...I know it is vague, but I don't remember what hose it was. That tube on the intake pretty much fell apart and the hose blew off. Required a new intake.
 

Ferocious

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If you have a plastic crossover on your manifold, that would be the first place i'd check. They are notorious for cracking.

8892d1119760665-98-gt-intake-manifold-leak-crack1.jpg
 

SWFLGT

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Thanks for the quick responses!

If you have a plastic crossover on your manifold, that would be the first place i'd check. They are notorious for cracking.


Thanks for the picture. I went back out to take a look at it again and sure enough, in that exact spot that is circled there's a hairline crack about an inch long...lucky me!:tongue3:
 

Ninety8stang

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Good ole plastic crossovers never fail. I guess your car never made it to the recall. Haha
 

95opal

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Even if the crossover was replaced with the newer version. The actuall intake itself is known for cracking around the mating area were the rubber gaskets seat, one reason I would never run or own a stock intake mod motor. Ford dropped the ball when they made that set up.
 

nightfire

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Even if the crossover was replaced with the newer version. The actuall intake itself is known for cracking around the mating area were the rubber gaskets seat, one reason I would never run or own a stock intake mod motor. Ford dropped the ball when they made that set up.

Exactly. This is where I believe Ford designed even the PI intake on a "bring your child to work" day and things got mixed....

Yes Ford replaced the crossover with an aluminum piece, but that aluminum crossover doesn't extend 100% to the thermostat housing. It reconnects back into the plastic manifold before connecting into the thermo housing. This is where 90% of PI manifold cracks occur.

This on my stock 02 GT PI manifold (shown from the underside). You can see how the aluminum crossover mates back into the plastic intake before going into the thermostat housing. This is where mine cracked an barfed coolant ALL OVER the engine bay

osbfv8.jpg
 

SWFLGT

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Thanks for the additional info.
I am going to replace the intake with a stock PI intake for now since I already have it and when I do the heads I will put something better on.
 

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