car temp gauge reading hot engine still cool

Asked by Jan 21, 2016 at 10:23 AM

Question type: Maintenance & Repair

I have a 99 Buick century it had overheating
problems so I replaced the water pump and
thermostat flushed out the radiator and put
new coolant. It has been driving just fine in
town today I took it on the hwy and about 13
miles out my temp gauge shot up to high
and car started loosing speed. I pulled over
and checked my engine was not hot radiator
cap was not hot and car started right back
up.I turned the car on and turned the heater
on car fan fine about another 5 miles then
the same thing happened. *heater was
blowing cold air* so I checked it again
engine still cool as well as the radiator cap.
Could a sensor cause it to run like this? Or
what else do I need to check

25 Answers

19,800

Sounds like there is air in the cooling system did you bleed air from system after replacing water pump and t-stat ? Also does your vehicle have the cap on the over flow tank to add anti freeze ?

Yes I bled it twice and yes it has cap on overflow tank. See I was thinking it could still have air also but not to sure. I bled it with the car on and lots of steam came out .

73,745

You guys I think are on the right track. Need to figure out how to bleed the system. Sometimes there is a bleeder on the thermostat housing to use, and some vehicles are tough to purge, so some shops have a tool to aid in purging the cooling system.

There are two spots to bleed it

73,745

Ya and it is a bugger to do completely. If only one side of you heater hoses are getting hot, the other hose is cool, that is an indication of air pockets.

19,800

Ok bleed air from system like this. Remove cap and add anti freeze to full mark leave cap off start vehicle and let idle and reach operating temp anti freeze will start to back up in over flow tank this is normal once t-stat starts to open anti freeze level in tank will drop add anti freeze back to full mark then put cap back on. All air will be removed from system.

OK I will try that. Thank you I will let y'all k ow how it works out.

One question firebird338 do I need to turn my heater on high when doing this?

73,745

Yes.

OK just checked hoses one is getting hot one staying cool

19,800

No

19,800

But would not hurt to turn on.

19,800

What hoses are you talking about the radiator hoses or the heater core hoses ?

19,800

If it is the top radiator hose hot and the bottom cool this is normal until t-stat opens if it is the heater core hoses heater core is clogged.

Radiator hoses I just drove it in town did great again on hwy temp gauge got To hot again but i dididn't loose speed this time. Checked fluids before driving it were low topped off yesterday. Tried purging air with radiator cap off thought it did the deal but it was a no go. When using the valves to purge air steam came out again.

19,800

Did you drive vehicle before both hoses hoses were hot ? If so did not wait long enough for t- stat to open.

No did not drive vehicle before but after I drove it only the top hose was extra hot and bottom hose not even warm

19,800

Sorry wrong info about the radiator hoses lower hose should get hot before the upper hose.

OK the upper one is getting hot fast

19,800

Sounds like the t-stat was installed the wrong way or you just got hold of a bad new t-stat. Have gotten bad t-stats brand new out of the box. If the t-stat is easy to get to remove and put hose back on with out t-stat and run vehicle and see if it still over heats.

OK u will try that.

19,800

Hey Rowefast do you know how to send a picture of a t-stat that has the drilled two holes in it may help with there problem. Do not no how to send pictures. Thanks

73,745

I just got back, and no, I was trying to figure it out since I've ben having a call for this.

19,800

Do you no how to get in contact with Ford Nut i have seen him send pics before.

73,745

I don't know what Ford is doing, I e-mailed him personal account and he never got back to me. Something going on with him.

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