I have been spending quite a bit of time under my 4runner (93 3.0), working on the exhaust system. With the extra attention I have been paying to the exhaust, I have started to hear what sounds like bubbling liquid in the cat after the car has ran for a bit and has been turned off. After driving the truck a little ways, I see clear fluid spitting out of the exhaust tip. I have just put a Dynomax muffler on and it is already (after <100 miles) turned ashy in color.

Anybody know what to expect as far as liquid coming from the exhaust??? I have been chasing a cooling system issue for quite some time (slowly loses coolant, but never leaves puddles). I have also checked for any milky oil or anything leading to HG problems, but can say with relative confidence that the HG is OK.

 

I always thought that a catalytic converter turns a lot of the nasty stuff in the exhaust into water+some other nicer stuff. Can that be it?

 

If this is the case, that would explain a lot.

 

Sounds like a bad head gasket to me. You can have a bad gasket that lets coolant into the exhaust manifold. Your oil would look fine in this case but you would experience the same problems you have detailed.

Not every time the head gasket blows dose it put coolant into the oil. Sometimes it doesn't. You could also have a cracked head causing the problem.

Do you see any White smoke when you start it up??

 

No smoke. Would there be any other indications to point towards the HG??
Is the discoloration on the new pipes and muffler normal or caused by too much liquid in there???

 

The bubbling fluid is probably coolant or water or whatever it is boiling inside your cat since that thing gets really hot. You should smell/feel/taste the fluid coming out of your exhaust tip next time to see if you can figure out what it is (OK, taste is probably not a good idea ).

 

Smells like nothing (coolant mix is 70% Prestone), color is clear.
It looks like condensation or water or whatever, it just starts coming out immediately after startup... before the cat is hot???

 

Mine spits clear fluid (water?) all the time, only at start up. Has since "new." (Feb 02). Always leaves a few droplets on my garage floor, or fires it on my wife's Accord.

 

I believe that if you have water coming from your exhaust, in small amounts (dripping), it is a GOOD thing. One of the by products of combustion is water, and when you're getting really good combustion you'll can have some of that by product drip out of your exhaust.

Someone correct me if I'm wrong.

 

if its jsut a little bit and isnt constantly pouring out of the exhuast, its probably just condensation, hot exhuast gas going through clod steel pipe

 

Sounds like its normal condensation to me.

 

Water is a byproduct of gasoline combustion. This should help explain it.

http://science.howstuffworks.com/question407.htm

 

Based upon what you've said about the color, smell, no smoke, etc., I have to concur that it's normal. Usually you'll see some amount of water from the exhaust after startup and it should diminish or stop dripping all together after the engine reaches normal operating temperature. Whatever moisture there is exiting the exhaust should be in its gaseous state after the engine and exhaust system are good and hot.

On the occasion that I started the engine and let the vehicle sit, there was almost ALWAYS a small puddle under the exhaust outlet of both my 2nd and 3rd gens.

 

I had that little bit of water coming out...then it steadily was more and more consistent. Then my catalytic converter stopped up. Then my head gasket went. Monitor it and note its consitency (sp).

 

Thanks for the insight guys. Longtime reader, just started posting.

 

The key difference in the cases sited is the lethal case of water in the exhaust is also a case of losing water from the radiator overflow tank.

You can add fluorescent dye to the radiator to be sure, or have that check done.

The key is to not let the leaking HG go long enough to warp the heads, or score a piston. Don't let the engine get hotter than 2/3 toward the red. Time to fix it, or have it fixed.

This advice is good for any engine, including the 22RE.

Richard

 

My family had a B^i( that "lost" coolant also. No puddles, nothing in the oil, nothing out the tailpipe. Dealer could not figure it out (go figure) until one day on the highway, worst case senario, the car could not hold speed/no power but was still running. Towed to the dealer to find out that the "worst case senario" block had cracked and the coolant was leaking directly into the cylinder.

I would guess you have a blown HG causing the coolant to leak into the cylinder. The antifreeze is probably burning off and only the water is dripping out.

OR the cat is doing its job and turning the exhaust into water vapor like it is supose to do and the loss of coolant is not related.

Here is a question for someone! If Funk_Runner does a compression check would it show if the HG was blown into the cooling sys? I would think so.

You could also do a cooling sys pressure check and see if there is a loss of pressure and it may sping a leak that you could see. Also try the fluorescent dye test like rdharper suggested.