Originally Posted By: meep
Yes, I misunderstood. So it holds pressure, shows no leaks, yet doesn't pressurize. Was the pressure test done when good and hot? Now I see why you are stumped.
1. thought one: engine is not actually approaching full op temp. can you verify temp? IR gun? multimeter with a temp probe? This happened to me with chrysler 3.3 - t-stat was opening too soon.
2. thought two: pressure is only leaking at op temps/under load - such as head gasket or something with the intake manifold/gasket.
This is a good one.
m
"Now I see why you are stumped."
Finally someone understands!
No, the pressure test was done cold about a week after changing the intake (~55° ambient temp I think. Mid-November in central OK on a warmer day). I didn't know you could test it hot. But I guess if it's not building pressure it wouldn't matter anyway. May have to re-test.
As for thought one, it's possible but unlikely. It acts normal, if anything it acts like it's too warm sometimes, but no problems. The oil comes out near perfect after 4-4.5k intervals (VSP 5W-20). Looking through the oil cap hole, the internals are only getting cleaner (in mediocre shape at first). I would think if it's not reaching full temp, sludge would be in order. The thermostat was changed when I did the intake (Nov. '15). I suppose it can't hurt to change it again, but I doubt it's the culprit. As I stated earlier, it warms quickly, and it always stays at the same temp according to the gauge, normal. I'm looking into an IR gun...
Thought 2 is also possible, but I feel the suspects listed are impossible. I changed the intake and there's no oil/coolant mixing. But a crack that expands with heat is possible, but only where coolant can't reach.
Now that I've changed the water pump to eliminate the variable, I'm giving it a day or two to ensure all air is out of the system and to see if pressure will build. If not, I think a replacement recovery tank and/or hoses are my next suspects.
