89 22re with 296k. it's pushing coolant out of the overflow tank. i think the HG is blowing past and into the water jacket. the WP and timing chain was replaced at 250k. 1st- is there anything alse that could be causing the coolant loss (no leaks found) (oil not milky). could tightening the head bolts stop the prob. 2nd - does the WP and timing chain need to be done when the HG is done since they are only 50k old.

 

No you don't have to do the timing chain and Water pump with a head gasket change. Do you see a lot of white smoke in your exaust when starting up. Have you checked your spark plugs to see if one is super clean compaired to the rest?

 

Any oil in the coolant? If it's blowing past the HG into the coolant jacket, you should see oil. If no oil, then it may be overheating and pushing coolant. Still could be a BHG, but could be other things.

PDX gives good info...steam in the exhaust (long after warm up) and a clean spark plug can help diagnose.

Leak down test can also help prove a BHG.

No you don't have to replace the timing chain or water pump when replacing, but make sure you tie the chain to the cam sprocket when removing from the head. Really helps keep it in time when putting back together. Otherwise, add a timing job to the list.

 

No steam out the tail pipe. no oil in the coolant either. runs strong except for the dissapearing coolant. thanks for the reminder about tieing the chain to the sprocket.

 

The mysterious disappearing coolant phenomenons continue!!!....I've been telling people, man, that its the freaking coolant fairy! Check to make sure you don't have quarters in your radiator.

Mine is leaking SOMEWHERE that I can't see. Its not overflowing in the tank, though. A bad intake gasket can also be a culprit, or so I've been told. Do a leak down test!

 

have you checked the thermostat?
how's the temperature gauge doing when it burps water?

 

Is it disappearing and you don't know where...or is it pushing coolant out the overflow tank past the radiator cap? Needing clarification.

Is it overheating?

How much coolant we talking here?

And it can leak through the intake manifold and/or throttle body (idle air valve). Small enough to drop coolant level overtime but not affect performance or create enough steam to notice.

 

Coolant overflowing the overflow tank could be due to a HG leak into a coolant passage. Had that happen on my '85. You can confirm by having a cooling system pressure test and look for the system pressure rising with the engine revs/load. Or you can do a chemical test on the coolant to check for exhaust gas contamination. Places like NAPA will have the test kit. Or you can pressurize a cylinder at a time and see if there is air leaking into the coolant.

 

You too huh?



I second the idea of a chemical tester on the coolant. You can rent them at NAPA for a good price.

 

not overheating at all, if anything it running cooler that before the prob started. runs just fine. no leaks at all. cannot duplicate while sitting in the driveway, the only inication i have is residue of coolant on the ridges of the air box where the expansion tank overflows. how much coolant is loss is hard to determine now- about 1/2 gal per week with only 50 miles being driven.

 

When mine did that, no real overheating, either, only if the coolant level fell too low would it start getting hot. Only overflowed under load while driving, that is when the engine cylinder pressure was high enough to blow the coolant out. Finally saw what was going on up a long steep hill where I was not moving very fast. Had the window open and smelled the coolant coming out and was able to see it before it evaporated.

 

I'm agreeing with the HG leaking into the coolant as the likely culprit. Do a leak down test or chemical test to be sure.

 

thanks for the help guys. thats pretty much what i figured. i'll have to go buy a leak down tester first