temperature mystery

pippo

Member
122
8
18
Florida
People,

87 sunbird GT non turbo, original owner. Now has 215,000 miles, daily driver, and I know our fellow member Doug (in PR) here has experienced this with his car. The problem is after say, 20 minutes driving with stop/go, engine heats up of course, but the needle on the temp gauge creeps up to past the 1/2 way mark. My guage is COLD at 7 oclock, and hot max at say 11:00. It starts to approach 9;30 and I get nervous, and turn on my toggle switch for the rad fan to cool it.What is it with our cars that makes the thermostat behave this way?

When newer the car's needle stayed steady at about 8:00. Just right. Yes, the thermostst is new, and new hoses, new rad (a while ago), recent anti freeze. This has been going on for years.

Thanks, people.
 

melsg5

Staff member
SUSTAINING MEMBER
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How about the temperature sensor, have you removed it to see if it has deposits and checked resistance?
 

pippo

Member
122
8
18
Florida
I thought I replied to your reply, mel, a while ago, but guess the site did not save my message- yes, I checked temp sensor and even bought new, and the new one checked out the same resistance as the old one. Now I have 2.
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melsg5

Staff member
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You say you throw a toggle switch to turn on the engine fan.
Is the fan still hooked up to turn on by the ECM monitoring temperature?
Have you rented an IR gun to determine what the actual engine temperature is?
 

92 Sunbird LE

Well-known member
2,182
49
48
Salinas, Puerto Rico
Mine does the same thing, without the fan and no TStat or heater core ,it will creep up fast, I try not to let it get past the lower first mark ever!

Coolant temp is critical on these 2.0 OHC engines. (Or blown head gasket)

On cool days , like 70* , I never have to turn on the fan, 80* + , I watch it like a hawk, and turn on the fan when needed.

Stupid design from GM letting a OBD 1 computer determine engine temp!

Real fix is to use a fan controller, aftermarket new or used Volvo ones from the wrecking yard or EBay.

Hope this helps ,Pippo....

Doug in P.R. 😎
 

melsg5

Staff member
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You never mentioned you have only two miles on the clock !
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pippo

Member
122
8
18
Florida
You say you throw a toggle switch to turn on the engine fan.
Is the fan still hooked up to turn on by the ECM monitoring temperature?
Have you rented an IR gun to determine what the actual engine temperature is?
Yes, it is, and I tested it years ago. Thing is, as was mentioned, GM stupid design does not turn fan on by ECM until temp shoots up almost to the red zone! Unbelieveable. Thats why I installed my toggle switch.
 

pippo

Member
122
8
18
Florida
Mine does the same thing, without the fan and no TStat or heater core ,it will creep up fast, I try not to let it get past the lower first mark ever!

Coolant temp is critical on these 2.0 OHC engines. (Or blown head gasket)

On cool days , like 70* , I never have to turn on the fan, 80* + , I watch it like a hawk, and turn on the fan when needed.

Stupid design from GM letting a OBD 1 computer determine engine temp!

Real fix is to use a fan controller, aftermarket new or used Volvo ones from the wrecking yard or EBay.

Hope this helps ,Pippo....

Doug in P.R. 😎
Right- I knew your car had the same problem as I remember you mentioning it a few years ago. So, Doug, can you post a link to an ebay supplier for such a switch/controller? That would be great! Assuming it is not too hard to install........
 

92 Sunbird LE

Well-known member
2,182
49
48
Salinas, Puerto Rico
Volvo: ( includes parts and EBay link)


EBay : adjustable cooling fan controller | eBay

Doug in P.R. :cool:
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G

G-593302

Volvo: ( includes parts and EBay link)


EBay : adjustable cooling fan controller | eBay

Doug in P.R. :cool:
Thanks, Doug. I didnt know! So, would that have a probe that screws into the current thread in the coolant housing? Or somewhere else?
 

92 Sunbird LE

Well-known member
2,182
49
48
Salinas, Puerto Rico
I might just hook up another fan in front of the condenser using the 140* switch I showed above on EBay, by getting some galvenized 1 1/4 " plumbing parts and adapters from Home Depot and putting them in one of the radiator hoses.

That way there is a backup in case the main fan or switch fails. ( Which has happened before)

Doug in P.R. 😎
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