1999 Suzuki Vitara, 2.0L / overheat at idle?

Question

When car is at idle for some time after running some miles the temp gauge start to reading higher than normal until it reach the red zone.

Rev the car between 2500 and 3000 will down the temp until its normal position, but after some minutes at idle the temp start climbing again.

When the temp is higher than normal the radiator's upper hose is very hot but the under hose is cold. After rev the car between 2500 and 3000 RPM, and the temp reach the normal level, the under hose starts to be warm and then hot after a minute.

I replace the thermostat with a new one, the radiator was checked and it is OK. The problem rise only when the car is idle for a while after it has been running.

Climb a mountain does not rise the temperature higher than normal, but stop the car or began to lower the hill at idle will do it.

Full problem at: http://www.suzuki-forums.com/suzuki-vitara-grand-vitara-xl-7/17464-1999-suzuki-vitara-2-0l-overheat.html

Any help will be apreciate!

If I remove the thermostat the temperature is always below the normal level. It reaches 1/3 as max when the car climbs a hill but then it decreases to the low position when the car lower the hill.

When the car run without thermostat both radiator hoses are hot, I think there is no problem with the water pump because without thermostat the temperature is always very low. I can see the water running thru radiator if I run the engine without thermostat and without the radiator cap, of course when engine is cold.

Some times, particularly on the night, when the car is at idle and the temperature is higher than normal, the calefaction's hot air is cold. After I accelerate the car to lower the temperature the hot air starts to be hot, very hot.

The engine overheat at idle until it reach the white/red mark, sometimes it overheat slowly and turn the calefaction on will down the temp to the normal level for a while.

There is no leak, at least it is not visible. This car has a fan clutch system, I suspected a fan clutch failure but the radiator's under hose is cold when the temperature rise to the white/red limit.

The thermostat is at the end of the radiator's under hose, next to the water pump.

It appears like there is no sufficient water flow when the engine is at idle, it can explain the cold air when calefaction is on before rev to 2500/3000 RPM.

After some minutes with the engine temp above the normal level and car at idle I can hear and see the overflow tank bubbling out.

Today I run the car for a while without t-stat and I can see bubbles in the overflow tank... I think there is a problem with the head gasket that might be passing air to the cooling system.

Air in the cooling system might cause low coolant and then that could explain my overheat problem at idle...

Answer 1

it could be a failing water pump, however, it could also be a faulty coolant temperature sensor. This is overlooked many times when cooing system problems arise. have that checked first, it costs 50 bucks to replace tops. as apposed to a new water pump $300 minimum! Good Luck

Answer 2

Seems like your radiator cap is bad it's supposed to create a vacuum and it's supposed to apply pressure to your radiator for it to function properly, so when it gets hot and the pressure applied to the radiator is coming out of the cap, check everywhere for leaks when your car has been sitting for a while check for puddles of coolant that may have come from your car...
Look at all hoses and tubes that go to your cooling system and even the smallest leak in your car can cause your engine to overheat...
But you can pick up a pressure checker yourself at a auto parts store and you can read the instructions and do the test yourself a lot less expensive then going to a shop and having it done, and any leak or bust in hoses is meant to be done if it happens but less likely will it...
A leak will occur in small amounts if there is one and you'll see it...

Answer 3

Have the water pump checked. Could be that the fins on the water pump are damaged in some way and aren't circulating enough coolant through the radiator when the engine is idling.

Answer 4

Check to make sure your electric fan is coming on. Cars tend to get hot at idle because there is no airflow. If your fan is not coming on, you have a problem with the fan or coolant temperature sensor.

Water pumps are bad if they leak. If you don't have a leak, it's not that.

Answer 5

at idle you are not pulling enough air .does it have a/c?electric fan? dirt as clog the fin on radiator and a/c condenser dirt between them. bad fan clutch? check these before you start buying a bunch of parts.just because radiator checked out doesnt mean the fin are open they may have only done a pressure test? good luck

Answer 6

It could very well be a failing water pump...