coolant in plug hole?

smiller9121 · Jan 10, 2012

I just bought a 98 gt convertible knowing it had a misfire. I figured it would be the plugs, wires or coil packs, so I started with the plugs. While replacing the #4 and #8 plugs (same 2 that were missing) I realized that the plug holes were filled with coolant. How did this happen? And what needs to be done to stop this?

Three50won · Jan 10, 2012

It might be something simple. Maybe the previous owner replaced the intake manifold gaskets and did a sloppy job. Or maybe he didn't connect the heater hose correctly and some coolant leaked. Or maybe didn't tighten the intake bolts properly and a little bit leaked. For now I wouldn't worry too much, I'd say just dry it out real good, clean and dry the plugs and coils, drive it up the road, and see if it happens again...

trombonedemon · Jan 10, 2012

smiller9121 said:
I just bought a 98 gt convertible knowing it had a misfire. I figured it would be the plugs, wires or coil packs, so I started with the plugs. While replacing the #4 and #8 plugs (same 2 that were missing) I realized that the plug holes were filled with coolant. How did this happen? And what needs to be done to stop this?

Do a compression check in the spark-plug holes that you found coolant in.

There is a possibility that your misfire is could be coming from low compression, being the the head-gasket is leaking. Look for bubbles of coolant when doing the compression-check. Either way your gonna have to replace you intake-manifold gaskets when taking the lower intake off, might as well make sure its not your head-gaskets.

trinity_gt · Jan 10, 2012

I'm going to guess your 98 has a PI intake manifold on it and the coolant is leaking from poorly sealed gaskets.

Pics of the manifold?

smiller9121 · Jan 11, 2012

The previous owner had just replaced the heater core, radiator and water pump. I don't see any wet spots on the engine or anything dripping from underneath the car, but I am losing coolant somewhere because I have to keep adding it. It is not mixing with the oil, so I don't think its a bad head gasket, and the car is not overheating, so I don't know what's going on. Also, the car is completely stock, all the way down to the wheels and exhaust, so I'm pretty sure it is a stock manifold as well.

COramprat · Jan 11, 2012

Check the intake manifold for leaks. Usually around the thermostat housing. Once water gets moving around under there it can wind up anywhere.

MyStangGT · Jan 13, 2012

Probably leaking at the rear coolant crossover in the manifold. It's pretty hard to see and locate. Lean over and look straight down at the rear of the manifold with a light and see if you see coolant. I had to replace my PI manifold years ago because of the plastic thermostat housing cracking. I messed up and used Felpro gaskets instead of OEM Ford gaskets. They seeped for quite a while but finally started leaking bad enough I had the same problem with coolant in the #4 and #8 holes. It gets in around the boots somehow. I just replaced the gaskets with Ford gaskets and all is good.

Also the coil on plug coils don't last much over 100K if your car has those. I've had to replace those on my car and truck. I bought the Accel sets off Amazon for that. Hope I have better luck with the after market coils.

coolant in plug hole?

smiller9121

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Three50won

trombonedemon

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trinity_gt

smiller9121

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COramprat

...I can take it. I think.

MyStangGT

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coolant in plug hole?

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...I can take it. I think.

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