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This car is making me crazy. Drove about 200 miles a few weeks ago, highway driving with the ac on. Temperature perfect. Got off the interstate and the gauge starts climbing. Turn on the heater for some extra help and cool air is blowing out. Both cooling fans working. coolant reservoir full. Thermostat is new. I am going to change the temp sensor, but not real confident that is it. Any ideas?
Chris b
The poor heater output suggests a severe lack of coolant flow, or a gas pocket in the heater core. I see that the reservoir is full, but is the actual system full? A Lisle funnel or the like can help with bleeding air out:
Use the same funnel to confirm that the thermostat is opening (even though it's new) and that the water pump is capable of moving coolant. Monitor ECT on the scanner and heater vent temperature at the same time to track if/when it starts overheating.
Is the pressure cap OE? New? It's possible to have a cap that won't hold pressure, lowering the boiling point. Failed caps can also cause coolant to vent to the overflow, but not back into the radiator.
And, because it's a Subaru, has a block test been performed yet? This is also easy to do with a Lisle funnel.
Thanks for the info. I will buy the funnel. Yes the cap is new OEM, but the thermostat is a new gates, I think. I purchased the OEM but have not yet installed it.
The funnel will certainly help to answer some of the questions. It will be a couple of weeks before I have any updates. This is a spare car, not everyday driver.
Thanks again, Chris b
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