I have to refill coolant about every 100 miles with no apparent leak. Temp remains in middle until fluid becomes low then rapidly rises.
I still have to perform more "run it and stare at it" trouble shooting, but here are some details:
1. I don't see any fluid on ground, or pooled anywhere. Thought I saw a tiny bit at top right of radiator, but could have been residual from servicing or perhaps very small seep.
2. Fluid is clean, as is the engine oil.
3. There is no apparent white "steam" leaving the exhaust.
1. After filling expansion tank, I run until warms, then watch tank began to lower as thermostat allows coolant to flow. I continue to add until level stays at full line and absent low light on dash. I have now run it at approx 1500-2000rpm for a while with cap off to bleed air out.
2. Now, after running at 15-2000rpm with stable coolant level, when releasing throttle cam and allowing it to idle, coolant quickly back-flows into expansion tank and overflows. It is possible that this is happening out on the road, but unseen (I don't drive the car often) thereby explaining no fluid on driveway.
1. Stabilize coolant level, then run it and stare.
2. Considering getting a pressure leak check at a shop.
Possibly related? or not?
1. Just started getting a "whiring" noise near belts and an acrid burn smell.
Any troubleshooting ideas?
-2001 Tribute, 6cyl 3.0 litre, 170k miles
-already replaced thermostat