So I recently found a coolant leak. First of all, there is no overheating issue. I only found the issue when the temp gauge spiked one bar while on the freeway then went back down to op temp and I checked the coolant to find it was pretty low. Like, 1/2 a gallon low. Which explains the temp spike. After replacing the coolant, the temp gauge has remained normal. But I've needed to keep putting ~12oz of coolant every couple weeks in the radiator.

Ok. So when the car is not running & raised from the front on jackstands overnight, it drips coolant from the bottom of the tranny housing. When its on level ground overnight, it doesn't drip. When under load while driving, after I shut off the car I can smell that sweet scent of vaporized coolant. A pressure test shows the system is not losing any readable pressure, however.

I've tried tracing the leak from where it drips (bottom of the tranny bell housing) on up the back of the engine, and thought I had found the spot where the water pipe and thermostat housing meet as there was a little bit of something wet around that seal, and it is the high point of the cooling system which would make sense why it drips when tilted back. But I replaced the water pipe/thermo housing seal, and all the gaskets on the thermo housing while at it, and it's still dripping.

How can I test specifically where the leak is coming from since I obviously can't see it anywhere? Can I can charge the system beyond its normal capacity in hopes the drip turns into a stream when under pressure that I can trace? I tried having a buddy rev and hold the engine up to 5k rpm, hoping the pressure would create enough fluid loss to find it. Didn't work. Next step is to pressure wash the entire area, jack up the front and see if I can hope to trace the trail to the source. Long shot. I could keep putting in more coolant, but that's not really a long-term fix for a project car.


TL;DR, coolant drips from bottom of tranny bell housing only when front of car is raised or driving under load, can't find leak, pressure test shows no loss of PSI.

thanks for any ideas. I'm running out

 

Bumps is

Not getting anywhere here and it's bugging me lol. How do u find a coolant leak that almost doesn't appear to exist? I've heard some pretty mixed things about that coolant sealer stuff they sell. Not feeling like risk in ng plugging something accidentally

 

Check the bottom of all your coolant hoses and low points. Could be one of the hoses going into the thermostat. Best way to track it is to drive around for a few minutes and then jack the front end up and check under it. (preferably with the car on so the system stay's pressurized). It will be hot, but look specifically at the low points of the coolant lines for drips.

It is difficult to tell where leaks are (non-obvious ones) after driving and letting the car sit due to the coolant being whipped around by the airflow under the car while driving.

 

Thanks for the reply. Yknow I've done all that already. And it's still a mystery. It's burning off the block while driving, the only time I can find it dropping is if the car has been jacked up from the front. Already took apart the thermostat and replaced all those seals, though the thermostat seal itself didn't fit 100% perfectly even though I used a 96 seal and thermo since my housing is a jdm model (from what I read jdm thermo housings require 96 only gaskets and thermos). I wonder if it's somehow getting out through there and burning off so it isn't wet. I'm gonna jack it up tonight and check that.

 

Possibly the water pipe itself can be leaking, that can be tricky to detect since it's pretty much hidden lol

 

Yeah I tried jacking it up last night and found no trace of a leak at all this am. No drip from the low point of the tranny bellhousing. Maybe the engine was still warm and it dissipated. This is bugging me.

How would the pipe itself leak? Wouldn't that require some kind of a puncture? I live in CA so it's not like it could have rusted. The leak is Def coming from directly above the tranny. But every hose is clean. And the freeze plug on that side doesn't exist- oil cooler line feeds into the hole