I have a 190? thermostat in my '95 Cutlass with a 3.1 engine. Even after having the system flushed, it takes a l-o-n-g time to heat up. A mechanic suggested the following as possible problems: A fin on the water pump could be broken, the radiator cap could be bad, put in a 210? thermostat. Help!


Have you tried replacing the thermostat?



I don’t get the “broken fin on the water pump” at all. This would cause the pump to be less efficient and therefore the motor would tend to heat up faster and perhaps overheat.

By slow to heat up are you talking about saying the coolant guage is slow to move into the middle of the guage (normal area)? Or, is the guage showing normal and you can’t get much heat into the cabin of the car? Is the 190 thermostat new or old?

Start with the simple stuff first, try a new radiator cap. Then try a new thermostat. Put the temp thermostat in the car that is the OEM spec. You should get plenty of heat from either a 190 or 210 thermostat.

A clogged heater core, bad valve in the heater controls, or crimped or collapsed heater hose could restrict hot water from the engine getting into the heater core. Flushing doesn’t always open up clogs.


I agree with Uncle T’s post.

Also, check to be sure your cooling fan isn’t operating when the engine is cold. It’s an electric fan turned on by a temp sensor, and it should not be running until the engine warms up.


Changing the temperature of the stat never changes the rate at which the vehicle heats up or cools down.
It only changes the temperature at which the system BEGINS to circulate the coolant. ( summer stat changers always misunderstand this thinking a cooler stat means it will run cooler when they’re having an over heat problem in the first place. )

It almost sounds as though yours is staying open. Just change with an o.e. temp stat to see if that is true.
Then try everything else suggested.


The gauge is slow to move to the middle. In fact, it never gets above 1/3. If I take a long drive, the car heats up well, but the temperature of the air seems warmer from the top vents than from the bottom. I’ve tried two new 190? stats (OEM spec), and neither has done the trick. I think the cap was new 30K miles ago when we replaced the engine, but I’ll start with that. Thank you!


Fans aren’t running on start up. Thanks for the tip!