Rep Power: 0

Need a little advice...driving home from work last night i noticed my temp guage was acting very erraticly.
It is an 02 Civic EX Coupe - 5-speed

I was driving about 35 mph for a good 10 miles then jumped on the interstate. I soon as I was on the interstate, my temp guage shot all the way up to H and stayed there for about 5 secs, then slowly went back down to the middle, or normal running temp. Every couple of miles (driving 60mph through construction zone) it would rise slowly to about 3/4 H and then slowly fall back to normal temp. This did this all the way home (about 25 miles). As i was almost home (driving 25mph through plan), it shot back up to H and slowly dropped down again.

It was completely normal driving to work today and I havent noticed any problems with how it is running. Engine does not seem overly hot and there are no fluids leaking from what i can see.

Any advice on what this may be? Could my thermostat be going bad or possibly the guage/wiring? Also, my check engine light has been on the last few days but i never really pay attention to it because it was contanstly going on and off when i had a high flow cat on there (the exhaust is now back to stock, as is the rest of the car) so i usually just ignore it and it goes away.

 
Rep Power: 0

Could possibly be the head gasket. Take a look at the coolant levels. If it is low and you fill it up and a little later it is low again then the coolant could be leaking into the engine and burning up which wont show any leaks on the ground. I had this happen to me and was lucky to get it repaired by the powertrain warranty.

 
Rep Power: 274

If you have a CEL, go to autozone, borrow a scanner and scan the codes. Anything not emissions related (or even anything recently emissions related) could be a pointer to the source of your troubles.

What you described could be a failing water pump, blown headgasket, air in your cooling system or a leaking heater core. How many miles on it, and has the timing belt / water pump been done?


if this happens again, turn your heater on full hot and full fan and see if you hear a running water type sound - that is air in your cooling system. If there's no running water sound and the temp goes to normal and stays there, it may be just a thermostat issue.

Good luck.