Coolant leak on back of engine

[joedogg]

Hey guys, I've got this leak. Where its coming from is somewhat of a mystery.

It only leaks when the engine is hot and starts very suddenly, leading me to believe that it will only leak when the thermostat is open. Could be wrong about that, however.

It's located on the passenger side of the engine bay on the back of the engine. It is not a heater hose. I know this because I disconnected both heater hoses that are located on the driver's side of the engine and led back far behind the engine and put on a bypass hose. The heater did not blow hot, but the leak came back the same as ever.

The coolant is dripping directly onto an O2 sensor located on exhaust pipe. I've removed the wheel and looked around in there, I cannot find a thing that could be causing this problem. Any ideas on what could be leaking? I've got to get this fixed ASAP!

I appreciate your time, guys! Thanks!

 

[SHO U UP]

Hey guys, I've got this leak. Where its coming from is somewhat of a mystery.

It only leaks when the engine is hot and starts very suddenly, leading me to believe that it will only leak when the thermostat is open. Could be wrong about that, however.

It's located on the passenger side of the engine bay on the back of the engine. It is not a heater hose. I know this because I disconnected both heater hoses that are located on the driver's side of the engine and led back far behind the engine and put on a bypass hose. The heater did not blow hot, but the leak came back the same as ever.

The coolant is dripping directly onto an O2 sensor located on exhaust pipe. I've removed the wheel and looked around in there, I cannot find a thing that could be causing this problem. Any ideas on what could be leaking? I've got to get this fixed ASAP!

I appreciate your time, guys! Thanks!

It probably does involve a heater hose. Generally the heater hoses tend to rot and will swell and leak from the inside out. The two on the firewall you seem to have looked at so let's not count those. There are other hoses and fittings that connect to the heads. My guess on the passenger side is its one of the two hoses going into the heads and its just running down. There is a plastic "T" that always breaks and the two hoses that attach to the heads tend to rupture also. Best way to check is to use a pressure tested kit. But then again, another thing it could be is the degasser tank. They like to split at the seams or the cap could be bad. Find someone with a pressure kit and it'll make life so much easier. I ended up buying one as I was changing out hoses on my friend's '99 every other week it seemed like. Keep us posted.

 

[joedogg]

Thank you! The degasser tank is the coolant recovery tank? I've checked that thing up and down and actually is cracked and leaking slightly.

However, that's not this leak. It is barely leaking a drop. You're probably spot on with that plastic T thing.

 

[SHO U UP]

Thank you! The degasser tank is the coolant recovery tank? I've checked that thing up and down and actually is cracked and leaking slightly.

However, that's not this leak. It is barely leaking a drop. You're probably spot on with that plastic T thing.

Glad I could help. Yes, the degasser tank is the recovery tank. And even though it may appear to have a small leak, when under pressure the crack can open up more and shoot more than just a drop of coolant. If it is indeed the "T", it'll be a much more easier fix than having to replace the two hoses on the heads. Good luck with it.

 

[joedogg]

Any word on reference points on where I can look for this T? Should I get at it from the top of the engine, or from the wheel well? Also, is this a "Remove the intake manifold" sort of job? I can do it, I'd just like to know beforehand if I should pull that thing off of there.

 

[SHO U UP]

Any word on reference points on where I can look for this T? Should I get at it from the top of the engine, or from the wheel well? Also, is this a "Remove the intake manifold" sort of job? I can do it, I'd just like to know beforehand if I should pull that thing off of there.

The "T" is right near the power steering pump and the fuel rails. IIRC, you can follow one of the top lines off the degasser tank and it should take you right to it. A couple pulls on it and you should be able to see if its broke or not. When I was working on that area, I found it easier to remove the intake and lower intake manifold. But then of course, I had to replace the two hoses to the heads instead of just the "T". Some folks just remove the power steering pump and do it through there. I didn't want to go that route personally.

 

[luigisho]

OF course, a couple pulls on that plastic connector might guarantee that it's broken. Better have a spare on hand before you monkey with any of the small plastic hose connectors. At this age they break easy.

 

[joedogg]

OF course, a couple pulls on that plastic connector might guarantee that it's broken. Better have a spare on hand before you monkey with any of the small plastic hose connectors. At this age they break easy.

Heck with it, I'll break it. I can bike to the store.

 

[SHO U UP]

:laugh_ti: That's the spirit bud! Luigi is right. Every time you go and take apart these things nowadays, you risk breaking EVERYTHING you touch.

 

[luigisho]

Heck with it, I'll break it. I can bike to the store.

A parts bike is very important if the SHO is your daily driver.

 

[luigisho]

Oh yeah, and sometimes the parts store has them on the rack and sometimes they don't. Get one first. Been there already this summer.

 

[joedogg]

Got ya! Alright. It's basically just a T for a 5/8" coolant hose?

 

[luigisho]

Last I remember, yes.

 

[SHOZ123]

That tee is 3/8" if it's the one going to the degasser tank.

 

[luigisho]

That tee is 3/8" if it's the one going to the degasser tank.

Paul would know. He sent me a killer brass replacement when mine went.

 

[SHOZ123]

But the original back of the engine leak would probably be the heater hoses. Both come off the water pump and are part metal, part hose. Cut the aluminum factory crimps off and the just replace the rubber hose. Don't bother with the U shaped one that comes off the bottom of the water pump.

Another bad one and a bit more difficult is the oil cooler hoses. They are metric sized and SAE heater hose will work but not well. The one that usually goes bad is the one to the water pump. It can be replaced with of the shelf NAPA hose that you trim to fit, but I can't find the part number now.

Edit: found the oil cooler hose part number.... Gates 18431

 

[joedogg]

I did the oil cooler hoses a while ago. Funny you should mention that.

I was surprised coolant went there. Kinda liked that the functionality existed.

 

[luigisho]

Not to hijack but ****, I might hit you up for the pressure tester. I still haven't fixed the running hot problem.

 

[SHO U UP]

Not to hijack but ****, I might hit you up for the pressure tester. I still haven't fixed the running hot problem.

Anytime this weekend you're free bro, I'm game. I'll be home past 2:00 pm on Saturday and home all day Sunday. You gotta leak too??

 

[joedogg]

Pulled the intake off, but still haven't found this dastardly bugger of a leak. I'll have to put the intake back on just enough to run the engine to hot and remove again this weekend.