A friend has a '95 MC, and is using coolant, has coolant in the oil and exhaust. How can we figure out which head is leaking? If it's the front head, we may replace it ourselves.

I believe he got a quote (for both) for $800 from a couple guys he sort of knows. Good price? Those people say they replace many head gaskets on the 3.1's.

It might only be the intake gasket. They are a common failure, there is an aftermarket intake gasket that is one piece instead of two seperate gaskets.

if it IS a head gasket and not the intake manifold gasket, you can usually pull the plugs and look at them to see if any of them have a sort of white coloration to them. Also, usually if a head gasket is bad there are lots of air bubbles in the coolant when the engine is running

There is definately coolant in the oil. Could that also be from an intake gasket (I forget)?

If there are bubbles in the coolant, could that not be from an intake gasket?

If the plugs are white, could that not be from a head gasket?

Basically, can any of these symptoms prove it's one and not the other?

Coolant in oil - yes

Bubbles in coolant - doubt it, especially if bubbles are rapid

Plugs are white - yes

ether way, you need to tear the top part of the engine off. If the intake manifold gasket is bad, you need not to go any further. If it's good, you needed to take that off to replace the head gaskets anyway, so go on to the head gaskets. BTW, you definately shouldn't be running the engine any more that you ABSOLUTELY need to if there is coolant in oil.

take the belt loose so that the water pump does not run collant through the system. remove the thermostat housing. turn the engine over and watch for bubbles. which ever side the bubbles are coming from is the side the head gasket (if it is a head gasket) has gone out.

i have done this a few times before but it has always been on a v-8. i have never had to try it on anything else. hope it works, good luck.

could you post a pic of the thermosatat housing location?

here is something to try. Get a tool to pressurize the cooling system ( i believe it's on Auto-Zone's tool loan program, it attaches to where your coolant pressure cap goes). Put about 15-20 psi of pressure into the cooling system and then pull the plugs out one at a time and listen for air/coolant bubbling. If there is no air leak or bubbling coolant noise in any of the cylinders, then you have an intake leak.

interesting test, rich, I would have never thought of that. I'll have to keep that in mind next time I have a similar problem

[QUOTE=dwalmop]interesting test, rich, I would have never thought of that. I'll have to keep that in mind next time I have a similar problem[/QUOTE


I had to remove my upper manifold and replace the gaskets. What a job that was. This is a commen problem with this motor. I believe they should have a recall on this issuse. Your going to need a torque wrench and know your torque angles to do this job.

Be very carfull that year is known for rear heads cracking. Also the push rods have 2 different sizes intake 1size and exhaust a different size

Hmmm, it seems like our Montes all have similar problems. Thus far I've read about problems with fuel injectors, turn signals, and intake manifold gaskets--and I've had them all replaced.

Hmmm. Shit like this makes me think that manufacturers should be required to warranty cars a lot longer or at least fix common problems for free.

I just had my intake manifold gasket replaced. Fortunately, there was no coolant in the oil or engine. But it leaked like crazy.