Heater temperature varies widely

90 Bonneville. With the car warmed up and at steady speed, the heater temperature will vary from lukewarm to baking hot, perhaps every 3 or 4 minutes. Forces me to constantly adjust temp or open windows.

Temp gauge shows steady. Coolant level OK. Water pump maybe 2 years old.

This is an odd one. Any hints?

Reply to
Robert Barr
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Mine actually does the same thing sometimes.( manual system ) I think it might be a thermostat just not opening enough then opening suddenly. I got a new radiator & heater core in early 2004.

My temp gauge points to the second line and a little under when it does this. And it only does it when its really cold out, say under 28 degrees.

Harryface

05 Park Avenue, 32,672 91 Bonneville LE 304,883
Reply to
Harry Face

Sounds like air/bubble somewhere in your kooling system.

Reply to
Muhammed Mustafo Goldstein Jr

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