Disappearing coolant

[99RedDragonCamaro]

1999 Camaro V6

Here's what's going on......

About every 4-6 weeks my coolant temperature starts to get a bit hotter and sometimes will reach to the 3/4 mark (it will go back down to 1/2 way after about 30-60 seconds) but it still runs a bit hotter than usual. Come to find out I have to top off my radiator with like 2+ quarts of coolant and bleed the system of air (little valve near the thermostat). This has been going on for months. Traveling long distances seems to speed up this process.

Basically my coolant is disappearing. My car doesn't leak anything. I've even been underneath it even while it running to confirm no leaks. Its starting to get some age too. 113,000+ miles.

I'm thinking only two things could be going on here....

My coolant is leaking into the engine somewhere (maybe the oil) or its actually evaporating (because of the air in the system).

Any thoughts or similar experiences?

Thanks.

-Beav

[UDLOSE98]

Re: Disappearing coolant

hmmmm, are you 100% sure it isnt leaking?

If it were leaking into your engine oil you would definetly know by now, especially with that much coolant, you woullda spun a bearing or messed something up a long time ago.

Evap? I wouldnt think so?

[HokieBird]

Re: Disappearing coolant

Oh it's leaking from somewhere. Take it to a shop and have them pressure test it. My disappearing coolant mystery ended up being the lower intake manifold gasket.

[badinfluenceRS]

Re: Disappearing coolant

intake manifold...check your oil and see if coolant is mixed in there

that happened on a previous car of mine, so if that is the problem get it fixed promptly

it could be a head gasket but that would have been pretty obvious and you should have noticed that by now

[01Convert3.8]

Re: Disappearing coolant

it could be the lower intake manifold my last car had a very mild leak but i noticed a decrease in performance and all around downgrade in the engine. Have you noticed any reduction in power or mpg. Just take it into a shop if your up in the cleveland area there are a bunch of shops that will do free inspections and if my mechanics got some time i could refer ya to him up here. He's not the cheapest but hes very thorough and does good work.

[UDLOSE98]

Re: Disappearing coolant

how is your car running by the way? if its running crappy you may be in trouble

[CDNFB]

Re: Disappearing coolant

I believe that you have head gasket problems.

For head gaskets, the coolant doesn't necessarily have to get into the oil. It can be leaking into the combustion chamber and be burnt off. Remove and check the condition of your spark plugs. The plug that has no deposits on it (cause the coolant steam cleans the plug) is the cylinder that has the coolant leak. Also, with a head gasket leak like this, air gets injected into the cooling system by the cylinder and causes a vapor lock, which causes the temp to rise. When the temp gets very high the pressures in the cooling system move the vapour lock along to the rad where it gets vented out of the overflow/reservour. With the vapor lock gone, coolant flow is restored and the the temperaure drops. Then it happens all over again. If you see this temperature cycling happening with your engine then the head gasket(s) have failed and require replacement.

[99RedDragonCamaro]

Re: Disappearing coolant

Thanks for the replys all.

I did some searching on the forums here and the intake manifold seems to be the common denominator so far.

My car runs fine. I took into a shop about 4 weeks ago for a big tune-up, I failed to mentioned the problem, but apparently they didn't notice anything out of the ordinary.

I'm going to take it in tomorrow morning. I'll post what I find out.

What am I expecting to pay if its the intake manifold gasket?

-Beav

[badinfluenceRS]

Re: Disappearing coolant

I believe that you have head gasket problems.

For head gaskets, the coolant doesn't necessarily have to get into the oil. It can be leaking into the combustion chamber and be burnt off. Remove and check the condition of your spark plugs. The plug that has no deposits on it (cause the coolant steam cleans the plug) is the cylinder that has the coolant leak. Also, with a head gasket leak like this, air gets injected into the cooling system by the cylinder and causes a vapor lock, which causes the temp to rise. When the temp gets very high the pressures in the cooling system move the vapour lock along to the rad where it gets vented out of the overflow/reservour. With the vapor lock gone, coolant flow is restored and the the temperaure drops. Then it happens all over again. If you see this temperature cycling happening with your engine then the head gasket(s) have failed and require replacement.

it been going on for months so if it was head gasket he would probably be ****ed already...and would have noticed clouds of white smoke

[slow6]

Re: Disappearing coolant

someone Finally said it!
Are you getting more than ordinary clouds of thick white smoke from the exhaust?

Another thing nobody has mentioned (which might not be very likely) is it could be a leaky freeze plug

get a pressure test done

[BLLDOGG]

Re: Disappearing coolant

its either or and its costly non the less. let us know what the verdict is

[99RedDragonCamaro]

Re: Disappearing coolant

its either or and its costly non the less. let us know what the verdict is

Sure thing. Dropping it off in the morning.......

[slow6]

Re: Disappearing coolant

do you not know if its shooting out thick white clouds of smoke?

[badinfluenceRS]

Re: Disappearing coolant

I vote intake...if it's been going on for months, head gasket smoke would have been to obvious not to notice

[John G.]

Re: Disappearing coolant

some of these explanations seem far-fetched

I have the same problem, but everything checks out OK -- no smoke, all plugs the same, oil doesn't show coolant contamination, no performance/mpg change, no leaks, nothing

even if it were a pinhole somewhere on the top portion of the radiator, wouldn't it have gotten worse in a moderate amount of time ?