I found a coolant leak after noticing the level dropping more quickly than usual. Water pump and thermostat were replaced 10K ago by a mechanic. I remember the pump leaking before then, but I'm not ready to tear down just yet if it's only the t-stat or a hose leaking. The coolant is settling on the corner ledge where the block meets the oil pan. Any advice as to exactly where it's coming from? Water pump? T-stat? Thanks.





(this is also posted on TTORA)

 

I just happen to have mine partially disasembled to replace the timing belt and water pump, and looking at that leak I would check the thermostat housing first. Make sure the 3 bolts are still tight, and if they are take it off and check the gasket.

 

Sounds like a good idea.

 

I had a recent leak in my rear heater tubes to the back but that would be a differnt location, however are any of the small tubes on the firewall cracked?

 

I have a drip now, only when it's running. It appears to be on the front passenger side, where the a/c bracket bolts to the block. It drips down to the right front corner of the oil pan. Has anyone had this happen on the 3.4? It's definitely not the HG, or the engine drain plug which is also in the immediate vicinity.

Thanks.

 

It's tough to stick your head up there to see where it's really coming from, especially when the leak is very small. I usually try to follow the pink crusty's that build up due to the leak to try to find where it's coming from. Eric's idea about checking the torque on the three nuts for the thermostat housing is a good one. I've had a small leak from there before.

Did you use a genuine Toyota waterpump for the replacement? If so, the chances of the shaft seal leaking are slim. Did your mechanic ensure that the gasket surfaces were very well cleaned? Did he use the supplied metal & rubber gasket (if it's a Toyota pump), or did he make his own gasket with FIPG?

 

Do a pressure test. Some smaller parts stores have a pressure pump that they will hook up and pressureize the cooling system. Then you can look and see, without the engine running, where it's leaking. You may need a small mirror and a flashlight to look around corners.

 

If all else fails get some dye and put in the radiator.With a black light you may see where its coming from easier than just looking with a mirror.

 

Thanks for the tips everyone.

 

Looks like the water pump to me,Just by looking at how the coolant has stained the front of the block by the lower timing cover......or possibly the bypass hose that attaches to the water pump.I would rule out the t-stat o-ring,just because if they pintched it it would pour out coolant........need to tear it down.

 

After checking everything, it's not coming from the HG, water pump, or any of the usual suspects. It appears to be coming from the upper bolt hole on the block to which the a/c compressor is mounted. Has anyone ever had this happen? I assume someone would have to over-torque the bolt, cause a crack, and the crack finally reach a coolant passage. Any thoughts?