Well I'm still working on my poor 1.5L Protege. Neat little car.. if I could just get the last of the bugs out!

Latest thing..

1. Cylinder head replaced with re-manufactured head. Also brand new water pump. Car is running perfectly! I'm very happy about that part.
2. Flushed cooling system while everything was open, refilled with all-new anti-freeze and even a new cap.
3. Now car runs great, but temp fluctuates. Never overheats, but will rise up from 185 to about 195 (using OBD), then suddenly (like in 10 seconds) drop back down. A couple seconds later, back up, then back down again.
4. Also, idling in garage, temp rises until fans come on (195+?), then drops back down right away.

Never had a car do this. Doesn't seem quite right, but maybe this is normal for a Protege??

OR

The temps are fine, but there is something going on with with the gauge...?

I am thinking I have air trapped in the system. Or, could a faulty thermostat cause this? Any other ideas? Thanks

 

I think you need to burp the system a few times.