I have a 93 Accord. Lately the temperature guage has been moving to HOT when stopped at a light. As soon as I begin to drive, or just increase the RPMs, the temperature immediately drops to normal. I just replaced the thermastat, but no change. The upper hose gets very hot, so I assume the water is circulating. I jumped the fan switch to make the right side fan run constantly, but still no help. What ese can I check ? Assuming that the water pump runs off of the timing belt, is it safe to assume that the pump is circulating the water properly ? or can it actually stop pumping even if still rotating ? Please help ! Thanks.
Bob

7/16/03: here's an update .... when making right turns the temp. goes up ..... when making left turns it goes down ! I thought I was imagining this, but had someone else drive the car and tell me what they observe .... same result. I removed thermostat and temperature stayed "normal" . I checked thermastat in hot water and it appears to be working. My feeling (just a guess) is that the water pump is not working to full capacity. How is this possible ? Do the "fins" wear down ? It must be turning if run by timing belt .... correct ? Car has about 120,000 miles. Bought it at 113,000 not sure if water pump (or timing belt) have been changed. Can anyone explain these odd symptoms ?
Thanks.


Modified by zatman1 at 10:58 AM 7/16/2003

 

The water pump is driven by the belts, yes. So coolant circulation increases with RPMs, and the increased circulation is likely why the temp begins to drop when driving or revving. Plus when driving the rad is cooled by moving air, natch.

You say the upper hose is getting hot, so coolant appears to be flowing. I'd warm it up, have an assistant ready to shut the car off if necessary, and check parts of the cooling system. Things I can think of:

- Feel (carefully! use gloves!) different parts of the rad for heat. You may have a partial blockage or something that is only letting part of the rad transfer heat away.
- Is the heater core working? Check the internal heat just to make sure flow is good.
- Check that both fans come on (natch, this is the biggest problem likely if you're heating at idle)
- Hold the upper hose with a glove and try to feel coolant movement.

Edit: Naturally if you haven't flushed the coolant already, it would be a good idea to do so and properly bleed it as well, since air bubbles can cause all sorts of heating bullshit.


Modified by StimpyBoy at 4:56 PM 7/14/2003

 

Make sure the lower hose is getting warm, which will indicate that the thermostat is working. Check your water level, too much antifreeze and not enough water will cause the engine to overheat. How many miles are on the water pump?