I posted about this a while ago and I'm still having this problem. Back in Nov I flushed the coolant and replaced the tstat. Everything was fine until about Jan when the coolant started leaking out of the inlet fitting--this part (it connects the lower hose to the block and holds the tstat):


The leak wasn't too bad, just enough to wet about 1-2 square feet on the ground and keep it wet for a couple hours. I replaced this part with a new one and that worked for about a week or two. Then it started leaking again, but not quite as much. I then tightened the nuts more and that helped for about a week. Now it's not too bad but it still leaks and leaves a puddle.

The weird thing is that it only leaks if I don't run the engine very long. For example it'll only leak if I start the engine from cold and move the truck a couple feet. The engine might be running for a minute at most. If I let it warm up completely, it won't leak at all, or at least not enough to leave a puddle.

I don't want to tighten the nuts any more because they're already pretty tight and I'm afraid of stripping something. I don't have a torque wrench and I doubt I could even get it in there.

So what do you guys think is happening?

Steve

 

On my truck the pictured part is an alloy so it heats/cools differently then the intake mainfold towhich it is attached. My guess on you sit. is the mating surfaces are not smooth and since it happens before all the metals get heated(i.e. expanded) the coolant creeps down an small gap in the mating surfaces. I'd pull the t-stat and clean up the mating surfaces with extra fine emery cloth, replace the rubber gasket around the t-stat edge, make sure you clean the groove that it sits in as well, and use a small amount of coolant passage gasket maker on the metal to metal surfaces. This should stop the leak. DON'T over tighten the mounting bolt as you can crack that new piece you just got. I think it like 9 ft.lbs (snug with your grip in the middle of a standard 3/8 drive handle).

One last thought your have the T-stat facing the right way?

Hope this helps
Nathan

 

Is it possible that its leaking from where the hose attaches. And is running down under the housing?

 

I looked at the mating surface on the part and it seemed pretty smooth. I also cleaned the tstat gasket and looked for cracks. It's kinda hard to see the surface on the block but I did wipe it down.

The tstat should be facing the right way because I put it back the way I found it and it matches the chiltons pictures.

I'm pretty sure it's leaking from that part and not the hose because when I took it apart I can see the general area where it is leaking. The toyota red antifreeze left a crust around the part and the hose isn't wet.

Anyways, thanks for the replies, I'll probably end up using a piece of silicone to make a gasket. If all else fails, I'll seal it up with RTV.

Steve

 

Do you have the o-ring seal on the t-stat?? If you have that on, try buying a tube of FIPG from Toyota and letting it set overnight to dry.. and then add the coolant