96 Legacy Coolant Loss

[johnceggleston]

How did you arrive at that conclusion?

 

the symptoms you describe in the overheating event are an exact match to a over heat due to bad head gasket. however, i don't know enough to be 100% sure that something else couldn't also cause the same synptoms.

 

a bad head gasket lets exhaust gas leak into the coolant/water jacket around the cylinders. this put "air" into the cooling system which can reduce coolant flow causing a hot spot, and overheating. coolant is forced passed the seal of the radiator cap into the overflow resevior, as designed. if enought coolant is forced out, the resevior will overflow onto the ground. when the cooling system cools down, it will suck coolant back into the radiator, as designed.

 

my guess is that at this time, although the radiator appears full, there is an "air" bubble in the engine cooling system, displacing some of the coolant and limiting the systems ability to circulate coolant. if you leave it as it is, the next overheat will come sooner, easier, faster. just my guess.

 

if you turn on your heater during this overheat and the air from the heater is not hot, then you have an air lock in the engine. most probably caused by a bad head gasket.

 

i have read that when gaskets first start to leak, they don't do it all the time. so easy around town driving may not cause the overheat. also pressure testing the cooling system may not detect the leak. 9 psi is not much compared to combustion pressure in a cylinder. over time as the leak in the head gasket gets worse, the overheating will occur more often and a coolant system pressure test will probably find it.

 

i can't remember if you had a hydrocarbon test done? if the headgasket caused the overheat, there should be hydrocarbons in the coolant now.

 

members here are divided on the head gasket remedy. some repair the gaskets and check the heads in the process. the more severe thge over heat, the more likely that the heads will need to be reworked. some swap out the engine for a 2.2L. the better value all depends on whose doing the work and the cost of the used engine. since you have a 2.2L engine, if it is the haedgaskets, this could be a leftover from the overheat / bad radiator last year.

 

good luck.

[Olnick]

Very nice explanation, johnceggleston. Thanks.

[JStamberg]

the symptoms you describe in the overheating event are an exact match to a over heat due to bad head gasket. however, i don't know enough to be 100% sure that something else couldn't also cause the same synptoms.

 

a bad head gasket lets exhaust gas leak into the coolant/water jacket around the cylinders. this put "air" into the cooling system which can reduce coolant flow causing a hot spot, and overheating. coolant is forced passed the seal of the radiator cap into the overflow resevior, as designed. if enought coolant is forced out, the resevior will overflow onto the ground. when the cooling system cools down, it will suck coolant back into the radiator, as designed.

 

my guess is that at this time, although the radiator appears full, there is an "air" bubble in the engine cooling system, displacing some of the coolant and limiting the systems ability to circulate coolant. if you leave it as it is, the next overheat will come sooner, easier, faster. just my guess.

 

if you turn on your heater during this overheat and the air from the heater is not hot, then you have an air lock in the engine. most probably caused by a bad head gasket.

 

i have read that when gaskets first start to leak, they don't do it all the time. so easy around town driving may not cause the overheat. also pressure testing the cooling system may not detect the leak. 9 psi is not much compared to combustion pressure in a cylinder. over time as the leak in the head gasket gets worse, the overheating will occur more often and a coolant system pressure test will probably find it.

 

i can't remember if you had a hydrocarbon test done? if the headgasket caused the overheat, there should be hydrocarbons in the coolant now.

 

members here are divided on the head gasket remedy. some repair the gaskets and check the heads in the process. the more severe thge over heat, the more likely that the heads will need to be reworked. some swap out the engine for a 2.2L. the better value all depends on whose doing the work and the cost of the used engine. since you have a 2.2L engine, if it is the haedgaskets, this could be a leftover from the overheat / bad radiator last year.

 

good luck.

 

John, thank you for the good, in-depth explanation. That helps a lot. I'll look into getting the hydrocarbon test done (any advice on where? is that a dealer only thing? Or would some normal shops be able to do that as well?).

 

I really appreciate guys like you who are taking the time to help others out, without expecting anything in return. Keep it up!

 

Since the engine does have so many miles on it (over 202k now), I'm leaning towards finding a replacement engine, or simply selling off the car (we'll be moving to western AK soon, and we want to make sure the vehicle is worth taking with us). Either way, this is very helpful in knowing which course to take.

[johnceggleston]

John, thank you for the good, in-depth explanation. That helps a lot. I'll look into getting the hydrocarbon test done (any advice on where? is that a dealer only thing? Or would some normal shops be able to do that as well?).

 

i'm not sure about the hydrocarbon test. i've read that you can get a kit at autoparts stores and i'm sure dealers can do it.

i would start with calls to autozxone or advance auto, they're open on sunday. if you come up dry there, call a local garage or shop and ask. if you have to go to the dealer.

 

as i mentioned before, the more severe cthe overheat the greater the risk of damage to the heads and maybe / eventually the block. but that would have to be a major over heat, i think. you may still be able to drive it around town for a while. adding coolant as needed. eventually, if it is the head gasket, you will start to get oily gunk in the radiator and over flow tank.

i sent you a private message.

[JPX]

if you turn on your heater during this overheat and the air from the heater is not hot, then you have an air lock in the engine. most probably caused by a bad head gasket.

 

Heed these words.

 

My heater slowly stopped working during the coldest time of year. This went on for a couple of months with some very mild coolant consumption.

 

Of course as luck would have it, when the weather got hot, my headgasket let go (due to a waterpump failure) and really overheated the engine, you could see steam from the tailpipe, stumbling of the engine, oil in the coolant and constant coolant consumption.

[88whitecat]

I'll look into getting the hydrocarbon test done (any advice on where? is that a dealer only thing? Or would some normal shops be able to do that as well?).

 

If your state requires you to pass an emissions test on a yearly basis, any garage that performs the inspections can do it for you as they use the same machine as to check the exhaust. I just had it done last tuesday for 10 bucks. A word of caution though: this is not a pass/fail test, more like a maybe/fail test. I have a known bad headgasket yet it still turned out good numbers and the mechanics determination was that the HG was fine.

 

Other than that good luck with it!

[JStamberg]

Due to the mentioned move, I have neglected to leave the update to my scenario. Here's what I found:

 

A friend and I decided to go ahead and start tearing into the engine... basically working our way towards the head gasket. I had previously put the dye in the coolant, but hadn't noticed any leaks.

 

We were just to the point of getting ready to remove the timing belt, when my friend (wisely) suggested I take one last look around for any leaks...

 

I cralled under the car... and voila... there was an itty bitty drip of (dyed) coolant on the bottom of the water pump.

 

As previously mentioned, the water pump had been recently replaced.... so I took it back in to the same shop, the part was still under warranty, and they gave me a discount on replacing it. I also had them install a new thermostat and timing belt while they were in there... just for good measure.

 

I've easily put a couple thousand miles on the car since then, and I haven't noticed any significant change in the coolant level in the overflow tank.

 

Sorry for the wild goose chase, gentlemen.... but as always, I appreciate your help. I brag to a lot of my friends how I was always scared of doing maintenance on my car till I found out about this board. You guys give me the confidence to tear into stuff I would normally never tackle on my own.