Way up to the line just under the red square when I am at idle?

JERRYSDADDY

MEMBER
2004 CHRYSLER PT CRUISER
4 CYL
2WD
AUTOMATIC
89,000 MILES

Driving down the road air conditioning works great and so does heat, however the temperature goes from the middle all the way up to the line just under the red square when I am at idle. I turn off the A/C and that does nothing. I start driving down the read again and the temperature will fall back to the middle of the gauge. Then again when I stop at a light for any length of time the temperature goes right back up and the temperature indicator comes on and dings then when I start driving the process starts all over again. I cannot tell if its a shot thermostat or bad radiator. I can hear the fan running and there is plenty of coolant in the system (at least the reservoir says it is correct). I do know the water pump needs replacing but the auto shop in my town said with what it is doing that shouldn't be the issue. I am not loosing any fluids anywhere.

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,348 POSTS

Welcome to 2CarPros.

Since the problem only happens when you are sitting in traffic and goes away when you are moving, that tells me there isn't enough air flow through the radiator. So, the radiator, thermostat, water pump and so on aren't the issue. Instead, either you have dirt and debris somewhat blocking the air flow through the radiator or the fans aren't working properly.

If you see dirt on the radiator, don't be afraid to take a garden hose and spray it to remove the dirt.

Now, when the engine is cold, confirm that the engine is full of coolant and not just the overflow. The cooling system pressure cap is located on the coolant outlet connector near the front of the cylinder head. I attached a pic of the cap. Only open this when the engine is cold.

One last thing, if the cooling system has never been flushed, you could even have a partial blockage causing it. Here is a link that shows how in general it is done:

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

Let me know what you find.

Joe

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