Overheating diagnosis, possible bad temp sensor?
 

Hi.

I was driving my 94 EX Coupe up the road that leads to Idyllwild recently, and after getting to my friend's house and pulling in the driveway, I shut the engine off and what do I hear? Boiling. In the radiator.

There's about 10, maybe 20 miles of mountain road up there (good driving!) and I tend to keep the engine at at least 3k to maintain momentum. The radiator was replaced within the last year.

The odd thing is that my guage, even sitting in the driveway listening to it boil with the key on, never went above the normal operating range - at all. Ever.

My question is; is it likely that I just overworked the pip-squeak radiator? I've read that Civics tend to need radiator upgrades for track use, and seeing as how they could pass for a heater core in some cars, I can see why. The fluid level was fine before I went up the mountain, and I've had no problems since.

The other question is, should I look into replacing the temp sensor, or are these stock guages the 'dummy' type that really don't tell you much? (Many manufacturers program the guages to not register all but extreme changes so as not to upset granny on the way to bingo). The last Civic I had was a 91 base hatch, and it seemed to register changes fine (found out I wasn't running a thermostadt on the way to Orlando about a week after buying the car - engine temp dove after a few miles on the highway. Thanks, previous owner!)

Anyway, what do you think? I haven't looked up the burp procedure yet, but I don't think it was that because this car was a long-distance traveling car for my friend's business before I picked it up and he never had any problems with it.

Idyllwild. SoCal, right? I've done trout fishing in the mountain streams there.

Anyway, did you lose coolant? If so, you might consider replacing the radiator cap. It may have failed at the low pressure of mountain high altitude.

Yeah, that's a possibility too. I'll check the repair reciepts and see if it's on there at all, but that's a good possibility - I thought it might have something to due with the sudden change in elevation of about 5000 feet or so.

On another subject...any recommendations should I want to upgrade my radiator in the future? Mountain roads around here provide some of the best driving I've ever seen, and I'd like to be able to tackle them with gusto without worrying about overheating my engine.

Also, any opinions on the guage/sensor?

The stock radiator system should be fine if it's not clogged or leaking, and the radiator cap is functioning to hold proper pressure. First try just replacing the radiator cap and possibly flushing the cooling system.