22RE Cooling Diagnostic
 

Hey all, I'm having a weird issue and I'm sort of baffled on where to look.

Just a quick history. Re-did the timing chain and cover with new OEM parts (oil pump, waterpump, timing chain, yada yada) 1 year ago on a donor motor that I swapped in while I rebuild mine. I have a small oil leak from where I didn't get the head gasket to seal perfectly on the timing cover, because I did the timing without removing the head (I have now learned). I also have a coolant leak somewhere. I THINK it's coming from the water pump gasket, because that's the highest point on the engine where I can see coolant/water. (It's in the same area as the oil leak, but oil isn't fluorescent).

What it does: I can run fine with no apparent leaks (no drips under the truck) for months at a time. My stock gauge sender isn't working, but I have spliced in a temp sensor into the upper radiator hose. I usually run between 180 and 190 once it's warm. If I fill the coolant all the way full (top off the radiator, fill the reservoir to the full line while cool) and then take it for a drive long enough to warm it up, I will find fresh coolant in the engine near the water pump, and the radiator will be a bit low and the reservoir will be basically empty. If I continue to drive it at that level, I have no further leaks/problems, except that recently I've been noticing my temp gauge creeping up and I'd rather not run at 200+. Summer being here and all, I'm ready for long trips in the desert, and need cooling.

I just slapped a radiator compression tester on their and my cap holds 15 PSI no problem (didn't push it past that, so maybe the cap isn't opening?) And when I pressurize the radiator system to 15 PSI, I see/hear no leaks. The tubing and gaskets that run to my reservoir are questionable, but could holes/bad seals there be producing this "leak when full" behavior?

Like I said, I'm pretty stumped. I'd rather not do too much work on this, as I'm planning on swapping my fresh re-build back in in a couple of months, but I still need the truck to drive with confidence for the summer. Thanks!