packers15

I have a 92 runner with the 3.0 4x4 auto with 192000 miles. Timing belt and water pump done 2000 miles ago. Lately after this thing has been parked I have been seeing a small puddle of antifreeze towards the rear of the engine towards the drivers side. I have looked at the hoses and can't really see anything leaking. It does not run hot and all other fluids look clean. Any idea's of where this might be coming from or what might be causing it ?

sb5walker

Follow the little black hose from the lower back end of the throttle body - that hose may be leaking where it connects to a metal tube under the plenum:
http://personal.utulsa.edu/~nathan-b...05descript.pdf

Also, the hose going to the heater valve (on the firewall) is in that area. Further to the passenger side, there's an upside-down "U" hose that can leak, too. And it's possible for the metal coolant tube that's under the plenum (actually, it runs under the intake manifold IIRC) to develop a pinhole leak if coolant is allowed to remain in too long and become acidic.

If you can't find any hose leaks, then it's coming either from a leaking head gasket or cracked head/block. A coolant pressure test will help find the leak if you can't find it by inspection alone.

packers15

Wouldn't I have other symptoms if it were the head gasket ? I suppose the best way to find out is to get the pressure test. It doesn't leak all the time, just a few times after it had been parked, does not leak anything when running.

sb5walker

Not if it were leaking between a coolant passage and the exterior of the engine, instead of between a coolant passage and a cylinder, or oil passage. I think head gasket leak or cracked head/block is less likely than one of the hoses mentioned. But if you had inadequate percent of antifreeze in there, and the temps got well below freezing, you could have cracked something.

packers15

Antifreeze was just changed when the timing belt and water pump were installed, tested to -50. Could it possibly be a frost plug ? I have been all over/under and can't see a hose leaking. I drove it for a while and got it up to normal operating temp and then parked it again. It has sat for over an hour without leaking. It's got me stumped !

packers15

Think I may have found the culprit, saw a heater hose back by the firewall that was leaking a little and running down the hose. Still nothing on the floor this morning, so I am hoping that the hose was the problem.

sb5walker