Losing Engine Coolant

[newfiejeff]

I have a 2002 Pontiac Montana with 3.4 l engine. I have to top up the radiator bottle about twice a year with coolant. The motor has about 157, 000km now but when I purchased it had around 70,000km. I had to add since day one and it never got any better or worse. I don't see any that has leaked on the ground or around the engine. So where is going and I guess it is leaking and getting burned off.

Any thoughts.

Jeff

[shogunl]

Originally Posted by newfiejeff

I have a 2002 Pontiac Montana with 3.4 l engine. I have to top up the radiator bottle about twice a year with coolant. The motor has about 157, 000km now but when I purchased it had around 70,000km. I had to add since day one and it never got any better or worse. I don't see any that has leaked on the ground or around the engine. So where is going and I guess it is leaking and getting burned off.

Any thoughts.

Jeff

You probably have lower intake manifold gasket that is leaking. Leave it too long and you will wreck the enigne.

serch this forum or in Chevy Venture forum about itake manifold and you will get all the info you need.

[hufhouse]

You'll find more information than you really wanted to know HERE.

['97ventureowner]

Do you change your own oil? If so, how does it look? Have you noticed a buildup of a brownish mayonnaise type substance on the inside of your oil cap? Those are some signs that your intake manifold gasket may be the culprit.

[bradyBunch]

I have my lower intake manifold off right now on my 2002 Montana. I can see a brownish mayonnaise type substance (aka coolant) on the bottom front side of the manifold. I inspected the gasket around the water jackets but it doesn't look too bad.

I was wondering if the leak is quite evident when inspecting the gasket?

I don't believe I had a big leak. I was watching the oil cap when I change my oil and I noticed it was coated two weeks ago. The gasket was definitely leaking on the lower right side (near the thermostat) of the manifold.

[tec5120]

i used a tube of alumi seal on a friend of mines and sealed those leakey intake gaskets right up.............3 months no leaks............

[marcelo carrica]

you put the sealant on the radiator ,or where...????

[OHIODAV]

Hey, I quess I'm joining the mystery dissappearing coolant club. With half a brain can I replace these gaskets in my garage? Think I drove it 4 days when I found the coolant was going into the oil, parked it. since the daughter is 15, I would have a year to fix it, me and my son might spend that year doing the thing in the garage? any tips? since I'm that far do this too? I got , I think,, good pictures and instructions from autozone.com, need all new head bolts? Do those pour this stuff in the oil to fix coolants leaks work?? With 145,000 miles should I just replace? Was maintained by me since 81,000, ran great, all the time. Any advice is needed. thanks.

[davidson5557]

You mention you have good pictures and instructions at autozone.com. I can't even find 1999 Pontiac Montana on their site (or later years). Would you mind posting a detailed link.

Davidson

[OHIODAV]

HEY, The autozone site, I just went through the diy, free repair manuals, and found 90-99 montana with instructions for engine overhaul, intake and exhaust gaskets, all that stuff, found stuff from a Jasper site, from someone elses post here, new bolts needed! weird torque pattern.

[cdru]

Originally Posted by davidson5557

You mention you have good pictures and instructions at autozone.com. I can't even find 1999 Pontiac Montana on their site (or later years). Would you mind posting a detailed link.

Get a Haynes manual. It provides better pictures and details. The Autozone link is just a generic instructions for the 3400 engine and not real specific to the van.

[cdru]

Originally Posted by '97ventureowner

Do you change your own oil? If so, how does it look? Have you noticed a buildup of a brownish mayonnaise type substance on the inside of your oil cap? Those are some signs that your intake manifold gasket may be the culprit.

Depending on where you live, the mayo may or may not be a positive indicator of a problem. The only sure fire way of determining if there is coolant in the oil is to have it analyzed.

In cold weather, if the engine never reaches full operating temperature, naturally occurring condensation moisture can cause the same "mayo" effect as coolant. My wife's van is like this. She drives very little during the week, mainly about 5 minutes to pick up my son from school, or a quick trip to the store and back. Never long enough to burn off moisture. During the summer months the engine gets hot enough to burn it off, but now we get the mayo film on the oil cap.

It's only $20 or so to get your oil looked at, and could save you a couple hundred or more if you really don't need a LIM gasket replaced.

Originally Posted by bradyBunch

I was wondering if the leak is quite evident when inspecting the gasket?

Not usually. Sometimes you might see a crushed gasket, but it's not like a head gasket where you can usually see corrosion or an actual break (unless that is what the failure was in your case).

Originally Posted by tec5120

i used a tube of alumi seal on a friend of mines and sealed those leakey intake gaskets right up.............3 months no leaks............

Alumi seal is only a stop gap. It's like putting a band-aid on a cut when stitches were needed. Sure it might stop be bleeding, but you will be much better off in the long run fixing it correctly.

[OHIODAV]

Hey, thanks for the info, I found a cd for $4, going to try that, figure I'll be ok anyway. Going to label and take pictures, take apart, back together, how hard can that be? I'm not in a hurry. hope that the blown gasket looks blown so I feel good putting it back together.

[cdru]

Originally Posted by OHIODAV

Hey, thanks for the info, I found a cd for $4, going to try that, figure I'll be ok anyway. Going to label and take pictures, take apart, back together, how hard can that be? I'm not in a hurry. hope that the blown gasket looks blown so I feel good putting it back together.

Plan on a long weekend or 3 days. How much work have to done on vehicles before? If all you've ever done is oil replacements, you are going to be in over your head. It's not particularly hard, but there is a LOT of things that you will be removing.

Are you doing the intake manifold gasket or the head gasket? The steps are the same for either, but the intake gasket stops before you remove the heads. Removing the heads will take an extra couple of hours as you have to remove the exhaust manifolds, exhaust pipes, engine mount, AC, etc. If you do remove the heads, plan on your heads being in the shop for at least a day being resurfaced. You also should resurface both of them. Part of the resurfacing they should check for cracks or other issues.

[OHIODAV]

Hey, I've done brakes, shocks, gas tanks, tie rods, tune-ups, and such. never had problem back together, just a little trouble apart, rusty stuck crap and all. I hope that as I get to the intake gasket its plain to see thats it. I've got as long as I want, hope to be done by jan 08, daughters 16th b-day. Thanks for all advice.