Why is the coolant tank always empty?

Guys:

My 2000 Montanna with 48k miles seems to be going thru the coolant like crazy. Its slowly getting worse. Right now the coolant tank goes empty every two months. I swear it never neaded coolant the first year or two, then about every 6 months I added some, now every two months I am refilling the tank completely. I don't smell any (does the new stuff smell like the green stuff does?). No leaks in the driveway. I looked at the front of the engine where the intake manifold meets the head and there is no sign of an obvious leak. It looked a little damp, but this seemed pretty normal to me. Can't see much else with all the tubes, wires, ducts, etc running every which way. I've also notice the idle is getting a little rougher, misses a little, but wasn't sure if that was just a function of age/miles. Any ideas? I have the factory extended warranty, and it runs out here in a few months on time (5yrs). Thanks.

Keith

Intake gasket is leaking internally. Pop off your radiator cap, does it look like its covered in brown mudd? If its leaking internally, the coolant is leaking into the engine oil. This is BAD because it does not lubricate like oil and can ruin your engine. Pull out your dipstick when the car has run and is warm, if you see bubbles on it, thats the problem. take it to dealer ASAP before the warranty runs out and get this fixed. Don't let them tell you its "normal" because as soon as that warranty runs out they'll say "looks like its the gasket, but we aint gonna pay for it cause its out of warranty". Just take it in and have them replace the intake manifold gasket with the newer spec. one that is supposed to address this issue. If you don't do it now, you'll be sorry. I only hope your motor isn't damaged (leakage like this has been known to cause camshafts to snap, resulting in engine replacement)

I agree with Umina, get the intake gasket replaced ASAP, as severe engine damage can occur if too much coolant gets in the oil

Well, there was about a teaspoon of brown coalgolated creamy stuff around the radiator cap. I'm guessing this is oil. The oil itself on the dipstick seemed ok, brownish color. Hard to tell much from the oil though. Guess its off to the dealer for a check-up. Should I demand they check the oil for coolant deposits and coolant for oil deposits if they insist its normal coolant usage.

Thanks guys,
Keith

No such thing as "normal coolant usage".
The cooling system is a closed system, ideally nothing should get out. Some drop in level due to water evaporation or air working it way out may require a small amount of coolant to be added from time to time, but refilling the empty coolant tank every two months...engine idle changed....as was mentioned above you have a leak into the intake, and the engine is burning it off.
You may be lucky and the oil isn't being contaminated..yet.

I read that Dexcool can start to form a sludge when there is excess air in the system due to low coolant level.

Have the system pressure tested.

Well, it was the intake gasket. Replaced and coolant flushed under the extended warranty. Dealer was very good about it, even though we had some discussion on who pays for the coolant flush. They finally agreed to it.

Keith

My Pontiac Montana's heater blower stopped working on except on high so I was surfing to find some answers and instead came across these posts about coolant and manifolds etc. My dh just mentioned the other day the coolant lite was on and he had to put Peak in it. I showed him these posts. Sure enough our intake manifold gasket was leaking for sure externally but most probably internally but dealer wouldnt admit it. Either way because of this info from you guys you saved me a bundle of money because I knew what to say and they (after calling Pontiac etc) finally agreed to fix the intake and blower resister for the $100.00 down instead of normally 70 for diagnostic test and $790 to replace intake!! Thank you so much. I also had them fix my air bag light problem cause something with passenger seat belt they split the cost 1/2 so I paid additional $125 to get that fixed. Same problem with drivers side and airbag light!! but it was still under warranty back then and was repaired back then. Now if I could just get them to fix my radio/screen lcd thing. I cant see the station or time because most is blacked out. OH well. sighhh, Besides all the problems I love to drive my van and its comfy for me. thanks everyone.

Good deal. Thats the power of these boards. Knowledge is power.

Keith

For anybody interested, an automotive consumer protection association here in Canada is conducting an online survey regarding the gasket problem, attempting to gather data (and faulty parts).
You can fill it out at www.apa.ca; proceed in official langage of your choice and scroll down to "Investigations" to find it.