Hey Guys, funny thing happened on the Hwy today and I'm lost for ideas. My temp gauge has never had a problem till today. Its always been just over half way up since I bought the car. Now today, when I went on the Hwy I noticed the temp gauge drop to about 25% when Im at high speed. When I get back to the city and drive slower, it goes back to normal...Now I know what to look for if things get HOT.....but not the other way around. New Temp Sensor about a year ago, check wires, no cuts. No codes, or engine trouble light. Engine seems to run ok and no over heating.....Flush about same time as Temp Sensor change. Soooo what can cause the temp to Drop and high speed?

Thanks in advance
Chebucto

 

Thermostat old?

 

You can hook up a OBD-II scanner and check the temp when it's not normal. Also, I have seen thermostats break.

 

Yes, never changed the thermostat, but why would this cause the temp to drop at high speed? I would think that it would rise. Also, if it is the thermo, will this cause problems till I change it? Problem is that one bolt on the housing is seized. I have the thermo to change, but I cant get the other bolt out......and Im sure I dont want to strip it.

Chebucto

 

If the thermo is stuck open or broken it will allow the temp to raise to normal full open temp like city driving or idle, then when you drive down the freeway you get more air and it will run cold. A cold engine wears faster and uses more gas.

As for the stripped bolt, if you can't get it out, drill it out and use vise grips to get it the rest of the way out when you remove the housing. Get a spare bolt before you go to town on it.

 

soooo, I could cut the bolt head off, and remove the housing cap,,,,and use the vise grips to remove the remainder of the bolt....correct?

 

Yes but it would be easier to drill out the bolt head.

 

Ok, I have a good drill,,,,use the metal bit....but what size...same size as the bolt head or smaller?

 

Use the size bit that is the size of the bolt shank. Remove the other bolt and match the bit to it. When you are drilling the head will free itself from the housing - that is where you should STOP drilling. That way you don't damage the housing.

NOTE TO OTHERS: When you experience a worn bolt head, don't over tighten it and replace it as soon as possible.

 

Thanks rspi, will update if the temp corrects itself....

Chebucto.

 

LOL!!! Temp will not correct itself. Hope you take your time with the drill. Have a good night.

 

I mean, the gauge will correct itself after the thermo is replaced.....lol....way too many beer tonight...

Chebucto