Running Warmer than Normal - 2009 base, manual

[slayerized6]

Temp gauge should normally be at the halfway mark. But you need to correctly diagnose your issue before you just throw parts at it. Did you test the coolant temp sensor to make sure it was still good? Did you use a scan tool to read the coolant temp from the OBD2 port?

[Deano]

I am not sure about the running warmer than normal issue. But by your description of the swollen hoses and the cracks in the expansion tank, those are classic signs that engine oil is mixing with your coolant via a failing engine oil cooler. The 2009-2011 Aveos have the engine oil cooler, and the internal seals harden and leak after 4-5 years. I am surprised that you managed to get so many miles on the car without yet having replaced the engine oil cooler.

Deano

[PalouseAveo]

I am not sure about the running warmer than normal issue. But by your description of the swollen hoses and the cracks in the expansion tank, those are classic signs that engine oil is mixing with your coolant via a failing engine oil cooler. The 2009-2011 Aveos have the engine oil cooler, and the internal seals harden and leak after 4-5 years. I am surprised that you managed to get so many miles on the car without yet having replaced the engine oil cooler.

Deano

Right on, thanks for input. I checked the Haynes manual and it seems like a relatively simple replacement. Would you recommend replacing the entire oil cooler unit (93186324) plus inlet/outlet seals? Or would it be OK to just dissemble the oil cooler and replace the internal seal (5199750)? Should the inlet and outlet lines also be replaced?

[Deano]

Good question. When I replaced my engine oil cooler, I had all new parts ready to go. New oil cooler, and 3 new coolant pipes. The new engine oil cooler comes with all the attaching seals. And the new pipes come with their all seals. Even though I might have been able to reuse the old cooler and dissemble it, and replace the internal seals, I didn't bother. Because i wanted to get the repair done as quick as possible with the least possibility of complications. If you have lots of time, it might be worth the bother to dissemble the old engine oil cooler and rebuild it with new internal seals. If you are careful, you can probably reuse the 3 coolant pipes if you install new seals on the old coolant pipes.

Deano

[PalouseAveo]

Thanks Deano!

[PalouseAveo]

Temp gauge should normally be at the halfway mark. But you need to correctly diagnose your issue before you just throw parts at it. Did you test the coolant temp sensor to make sure it was still good? Did you use a scan tool to read the coolant temp from the OBD2 port?

Thanks for the reply. No, I haven't tested the ECT sensor or used a scan tool to read the temp. I should be able to borrow an OBD2 scanner, but I'm not sure about testing the ECT sensor. Is that something best left for a mechanic? Could I do it with a multimeter, or would I need a specialized tool? The past few years I've been trying to as much maintenance myself as possible, but I admit there are some things a mechanic should do.

Regarding the temperature gauge. Mine has never gone to halfway in the 10+ years I've had it. It has always sat around or just below 3/8. Right now it sits exactly at halfway most of the time and goes slightly over sometimes.