Overheating Mystery

[Carbonics]

good tip on the lower radiator hose, will check it once I get the housing on.

I test drove it around after changing the radiator cap and it started to get hot after about 10 mins, but it didn't just spike up to the top of the temp guage like one would expect to see.

it got halfway up the guage and sat there, then slowly crept up to 3/4 of the way and sat there, then went down a little, back up etc - head gasket?

a shop I know of says they will charge $50 to figure it out, problem is they are 6 miles away and I don't want to pay $60 to have it towed. They seem like a pretty good shop, some may remember my 93 civic with the wobbly front driver side wheel - someone said bad tie rod end, $10 (general diag fee) later the guy said "yep" and replaced it

I just don't want to tow it and pay him $50 and it turns out to be something stupid I could have fixed had I thought about everything.

 

[CBDFrontier06]

If you've tried everything else, consider a partially collapsed radiator. My friend's El Dorado suddenly started overheating, and after we put in a new thermostat it still did it. The hoses were getting warm, but apparently flow was restricted enough for the heads to overheat.

The mechanic that fixed it described the radiator as having a partially collapsed core, instead of being 'plugged up'. A new radiator was the fix.

 

[Carbonics]

checked online to see how to test a thermostat and came up with this...

http://auto.howstuffworks.com/cooling-system8.htm

so I put it in some hot water and started to boil it...

approaching boiling point.

boiling away -

after removal from boiling water -

doesn't look like it's opening to me, even applied pressure on spring, nada, dunked it in ice water then back into boiling water, nada... unless I'm missing something.

seems odd that a thermostat would just fail like that, car is driven everyday, it was driven the night before and ran just fine - drive the next day and the thermostat is stuck?

 

[unDummy]

No, its not odd or rare. Thats how they fail. I replace mine every 30k or 3 years. Its a maintenance item even though everybody thinks that it'll last forever!

 

[Carbonics]

it opened, after 2 minutes of sitting on a red hot burner.

I guess the mystery is a mystery no more, thanks everyone for your help....hopefully this is the ONLY reason it overheated.

 

[Greggy_D]

Mr. Wizard is proud of you.

 

[Quest]

Like I've been preaching/explaining to some other BITOG posters on the board the other day: there are times when a thermostat fails w/o opening so my take is that there's no such thing called an AutoRad "failsafe" thermostat in keeping a thermostat wide open when it fails....

Carbonics-

Thermostats are wear-n-tear items as the engine thermal-cycles, your thermostat wax pallet inside the cylinder will fail eventually. The more frequent the thermostat cycles, the sooner it fails. Don't be surprised if yours fail sooner for like undummy said: this is a maintenance item and when it fails, it will either open itself wide (causing your engine to run cold, carbon fouling the EGR valve, never reached close loop, etc.) or never open at all (causing your engine to overheat).

For import vehicles I always pursue factory OE replacement unit for I have my fair share of "premature" failures of aftermarket units.

My 2'cs worth.