Engine Too Hot

Hi Everyone,

I am hoping you can help me with my problem of engine not staying cool on my 2000 Chevy Impala 3.8 with 120,000 miles.

I am having the common problem where the engine runs cool when I am moving on the highway but it gets really hot when I am stuck in traffic jams. What I have also noticed is that after the engine gets hot and when I get home and cut the engine, I see a constant coolant spill in the front on the driver side.

Here’s what has been done already. The thermostat has already been replaced. The mechanic tells me that the radiator is not leaking. He thinks the water pump is working fine. I have noticed that the fans kick in some times, however, I don’t hear them running when the engine is really hot. I know the intake gasket leaks a little oil every now and then but the mechanic doesn’t seem to think that is the problem. The mechanic basically can’t find the problem and that is why I am turning to you all for help.

Thanks in advance.

– Ankur

Has the radiator cap been replaced? If the cap is not holding pressure, the radiator will boil over. It’s easy to overlook and inexpensive to replace.

Ed B.

First…replace your mechanic. The new mechanic should make sure the cooling fan and cooling fan relay are working properly. The cooling fan should be running when the engine is “really hot”. These cooling fan relays can be intermittent at times and I think that’s your problem here. A good mechanic should have no trouble diagnosing this relatively simple problem.

The symptoms you describe are indicative of improperly functioning cooling fans. It’s very easy to check whether the fans work correctly or not. Why hasn’t your mechanic done this?

The water pump may not be working fine. The impellers inside the water pump may not be pushing as much coolant as it did when it was new. If the radiator cap and fans aren’t the problem, look into the water pump.

Thanks everyone for your reply.

I forgot to mention that I did replace the radiator cap just last night. I will know tonight when I am stuck in traffic whether that helped or not.
The mechanic also bled the system to remove possible air pockets.

I will take the car to a different mechanic to have the fan and relays checked. That sounds like a very good suggestion.

Also, by “really hot” I meant that I see the temperature gauge rise up some times to one thread below red but consistently stays above 50% mark. So it gets pretty hot some times.

Thanks again!

By the way, the cooling fans do work fine when I run the heater or the AC. I just don’t think they run when the engine gets hot. I will still have them checked out and report back.

Hi Everyone!

I had said that I will report back so here is status of things today. Here is what all I have done so far:

  • Replaced radiator cap
  • Replaced thermostat
  • Replaced coolant temperature sensor (CTS)
  • Replaced radiator fan relay “Fan Cont #2

The fan is now working as far as I can tell. I am thinking it was either the CTS or the relay. So I noticed that the fan now comes on at slow speed and it came on at high speed one time. The engine temperature does go up above the mid mark but it hasn’t yet gone up like it used to.

So I was feeling good about it until earlier today. I drove in to work with engine temp below the mid mark. Then when I came back out to my car during lunch I noticed a pool of coolant on the garage floor. I didn’t add any more coolant and I drove home with temps just a tad over the mid mark. It still didn’t seem high enough to trigger the high speed fan. Right after I turned the engine off, the car started spewing out coolant from the driver side. So it doesn’t normally leak but it does when I drive for a while and then park the car. I have already had a mechanic tell me that the radiator doesn’t have a leak so I imagine that’s not the problem.

So do you guys have any idea as to why my car spews coolant in this condition?

Your help is appreciated very much.

– Ankur