2001 Oldsmobile Alero car over heats

WEGTJ4

MEMBER
2001 OLDSMOBILE ALERO
6 CYL
FWD
AUTOMATIC
108,256 MILES

I had a check engine lite come had it checked it was po301 misfire in cyclinder #I have repaired my manifold leak, added new coolant(prestone 50/50). Replaced coil & changed oil. Car runs good untill in traffic car starts to overhaet what is the next thing to look at.

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

Hi wegtj4. Welcome to the forum. What do you mean by "traffic"? Following too close like a NASCAR driver, stop and go traffic, or lots of cars on the highway? If the overheating occurs when driving slowly such as in the city, suspect the electric radiator fan is not turning on. At highway speeds the fan isn't needed because there is enough natural air flow.

If the overheating just started after doing the engine work and refilling the coolant, there could be an air pocket that wasn't bled out. Coolant temperature sensors don't respond well to hot air; they have to be in contact with hot liquid. An air pocket by the temperature sensor can prevent the Engine Computer from turning on the fan.

Also look for a radiator fan relay. They don't fail real often, but to not overlook something simple, swap it with a different relay such as the AC compressor relay.

If the overheating occurs at highway speed too, check the radiator for rotted away cooling fins.

Caradiodoc