Running hot


Asked by Sep 20, 2015 at 08:41 PM about the 2003 Buick LeSabre Limited

Question type: Maintenance & Repair

Driving to work car started running
hot so stopped and the reservoir was
overflowing. Ended up driving to
work and pulling over when the car
would start running hot again. On the
way home the same day I filled the
radiator with water. While driving I
ran the heater all the way home and
it was blowing hot air and didn't run
hot. Drove it back to work the next
morning same thing happened,
didn't run hot. Then on the way back
home it ran hot again. I parked the
car for the night went back next day
after work and took the thermostat
out thinking it was sticking. After
removing it on the way home it ran
hot again as I got home. Next thing I
did was take the heater hoses off
and run water thru both until water
was clear. Then took off the upper
radiator hose and flushed from there
back thru the engine until the water
was clear. Put everything back
together filled the radiator with water
and cranked the car. Ran it in idle for
10 minutes then drove it for another
20 minutes. Car didn't run hot and
heater blew hot air. Then the next
morning it ran hot again so I bought
radiator flush and put it in. While I
was running it thru the system it
started to run hot again and the air
never got hot then there was slight
smoke coming from the engine. I'm
going to put the thermostat back in
and drain the flush out and put water
back in. When I run it if it runs hot
again I am all out of ideas. Help

9 Answers


chech the temp switch that sends water temp to the computer( not the one that sends water temp to the dash)

1 out of 1 people think this is helpful.
Tom Harmon

Check the radiator cap to make sure it's seating tight on the radiator if the cap won't hold pressure it will do what you said ... When you fill the cooling system be sure to open the 2 small air bleed screws on the engine ... That engine is brutal to fill and gets air-bound if you don't open those 2 little screws (about 6mm)

1 out of 1 people think this is helpful.

Thank you I will check these tomorrow evening.

1 out of 1 people think this is helpful.

Have the upper and lower intake manifold gaskets been done? They're notorious for failure on the 3.8 L V6s. How many miles are on your LeSabre? The gaskets usually fail between 90,000 and 120,000 miles. Pull the oil dipstick a look at the underside of the oil filler cap. Is there white milky "goop" present? If so, the intake manifold gaskets have failed. It's NOT going to be a blown head gasket! The 3.8s rarely, if ever, blow a head gasket. Any water vapor coming from the tailpipe? Another indicator of an intake gasket failure on these engines. HTH. -Jim


Yes there was water vapor on the tailpipe last night. I'll check those gaskets. 130,000 miles and gaskets haven't been changed

1 out of 1 people think this is helpful.

Then you're definitely due! If you have this done, replace the plastic upper intake manifold (AKA Upper Plenum). Don't reuse the original one. They are notorious for cracking. Dorman Products sells a kit for this. Hopefully it's not leaking internally. If it is, change the oil TWICE immediately after the repair. If it's leaking externally you'll see small puddles of antifreeze on top of the engine once you remove the plastic engine top cover. Any "goop" on the dipstick or underside of the oil filler cap? HTH. -Jim


UPDATE: last night I pulled the thermostat housing off filled the engine with coolant as well as the radiator and reservoir. Replaced thermostat and ran the car up to running temp. The radiator hose sounded like a pump so I opened the bleed valve on thermostat housing until steady stream of coolant was coming and closed it back. Continued to let it run for another half hour before taking it for a ride. Heater was working great and it didn't run hot. Just drove it to work this morning and it ran nicely. Thank you for the help.

1 out of 1 people think this is helpful.

Oh and I did pay close attention to the tailpipe yesterday and there wasn't any water vapor nor was there any goop nor was the oil milky.

Tom Harmon

Great ,,, The only compensation we receive is your satisfaction,, Thank You

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