Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Temperature Rising when Stopped / Idled

Hi everyone.

I have a 92 Honda Accord. This just started happening, but after I start the car in the morning or after work and drive it for 15-20 minutes, everything is fine.

After this period, when I come to a stop or put the car into park, the Temperature gauge begins rising until it gets to the “H”. I haven’t actually had it overheat yet as the light changes or I’m able to go, upon which the temperature rapidly drops back down.

I took the radiator cap off after driving about 30 minutes and steam shot out and some brownish liquid as well. I’m guessing the coolant in the radiator is pretty old.

I checked the Coolant Reservoir and it was empty, so I filled it to the “Warm” line, but the problem has persisted.

Do I simply need to flush my coolant system and get the old stuff out of there or is this a different problem?

Thank you so much.

- Pete

From the description of the coolant, it sounds like the cooling system needs service. But that may not be what’s causing the overheating when stopped. The problem might with the radiator cooling fan failing to come on.

Start the engine and let idle while at the same time watching the temp gauge. As the temp gauge rises, check to see if the radiator fan engages. If it doesn’t, there’a a problem in the fan circuit. This could be a bad fan motor, bad fan relay, bad coolant temp sensor for the fan, or a blown fuse for the fan circuit.


Brown coolant is definitely not a good sign. I suggest you have the coolant replaced, along with the thermostat and radiator cap.

As Tester said, it sounds like the radiator fans are not working. This is allowing the coolant to get too hot when the car is stationary. When you start driving air is flowing through the radiator and cooling the engine. The fans should be doing that when the car is not moving, but for some reason they’re not.

Check the fuses for the fans first. If the fuses are OK you’ll have to start checking the fan relay, the wiring, and the fan motors themselves. It’s unlikely that both fan motors would quit at the same time.

FYI you should NEVER remove the radiator cap when the engine is hot. You could get seriously burned. Wait until the engine and radiator have cooled before you remove the cap.

Thanks so much for the replies, I really appreciate it.

I will check the fans as you guys suggested, but I can tell you that a fan does come on for sure after the car is off. I can hear it, and it usually runs for 3 minutes or so after the car has been turned off. I’m a bit of a novice here (by a bit I mean completely) and you said Fans, plural. I will check to see if I can find another one, but the one all the way in the front of the car definitely comes on when the engine is shut off.

If I take this to a mechanic, how much do you think I should expect his estimate to be?

Again, thank you so so much.

Your car may have only one fan. Many newer vehicles have two small radiator fans side by side, so we tend to say fans instead of fan.

There is a temperature sensor in the radiator that turns the fan on and off, and if the fan comes on after you shut off the engine then the fan must be working. I’d want to visually confirm this, and I’d also do the idle test suggested by Tester to see if the fan is cycling on and off as it should while the engine is running.

If your car has AC the radiator fan, or fans, should also run when the AC is switched on.

You really need to do something about that rusty old coolant, however. It’s not helping anything.

Ok so here’s an update.

I did as you guys suggested. After work today I drove home about 30 minutes on the highway. I had my heat on full blast and the temperature gauge stayed at about 40% which is what its done in the past.

After I got home, I let the car idle and watched the gauge. First I checked the fan – Not On. Went back and watched the gauge. It started to rise a little bit, so I went and checked the fan again. It was on. Also, the temperature gauge seemed to level off at around 65% and wouldn’t really get higher.

I thought this was interesting so I went to check the coolant Reservoir. It was empty. I checked it after I parked at work this morning and it was filled to the “Max” line, but now after sitting parked all day and the drive home, it was gone.

Do you guys know what this means?

Thank you!