[infomanSS]

My Imp is a daily driver and I'm up in Ohio. I'm using the Meziere 118HD water pump and it works great in the summer, but in the winter it works a little too good. It's hard to get good/high temp from the heater even when the engine is "fully warmed up".

I was thinking of putting some sort of resistor / dimmer switch in place to make the pump work slower, then I could switch it back in the spring.

Anybody done something like this...suggestions?

 

[JonRobbinSS]

I wouldn't mess with the pumps wiring. I think these pumps already flow less then the stockers at anything above idle speeds. Instead I would look at adding something to the front of the radiator to block the cold airflow. A piece of cardboard to reduce the cooling area would do better.

What thermostat are you running?

 

[cletus284]

Your problem is probably a clogged up heater core. Its also possible that your thermostat could be stuck open. Don't mess with the pump.

 

[383LSxIMPALA]

Put a electric thermostat. I bought a perma cool trans cooler with a fan. And I came with an inline thermostat that automaticly turns on and shuts off the fan. Im sure they sell them for bigger cooling systems.

 

[JonRobbinSS]

Cletus has very good suggestions. Start with his, getting your system working right first. Then mess with blocking the radiator if needed but I doubt it would be.

I would not be cycling the water pump with a thermostat switch the heads need the constant flow.

 

[Bad Imp]

Instead I would look at adding something to the front of the radiator to block the cold airflow. A piece of cardboard to reduce the cooling area would do better.
What thermostat are you running?

When I was stationed in Fairbanks, AK, but there the temps were 30-40+ below zero and we had to block the cold air so the car wouldn't freeze up. Good question on the thermostat, put a higher temp in it first.

Your problem is probably a clogged up heater core. Its also possible that your thermostat could be stuck open. Don't mess with the pump.

I agree flush the heater core, check your thermostat and then see how it works. I agree with the other guys, don't mess with the pump.

 

[96capriceMGR]

Put a electric thermostat. I bought a perma cool trans cooler with a fan. And I came with an inline thermostat that automaticly turns on and shuts off the fan. Im sure they sell them for bigger cooling systems.

That would only help if the fans were programmed to turn on too cold.
If you put it on the pump you would have hot spots ong before the pump got turned on.

 

[RoadMonster 2.0]

Like already suggested...

Make sure your heater core is clean first.

 

[Marky Dissod]

Had this problem a year ago. Work backwards from the problem area.

Hot/cold air flap working inside the dashboard?

In my case, it was my 2nd guess; heatercore was so far gone, RMI25 and tens of flushes made no difference, but a new heatercore did the trick ... pretty much. Flushing the rest of the cooling system is never a bad idea (back and forth is how she likes it).

Besides the stock 180°F thermostat, there are now LT1-spec thermostats available in 195°F and 205°F.

It goes without saying that your fans should be programmed to work with the thermostat you selected (I suspect you are or were using a 160°F?). The later your fans come on, and the less air flowing through the radiator, the hotter the antifreeze gets, and the hotter the air blows through the heatercore and into the passenger area.

Partially covering the radiator is a time tested and proven trick. Start small and work your way up.

If it's that cold out, you don't need an external oil cooler. In fact, according to GM, if you're using synthetic motor oil, you don't need an internal oil cooler either. Many many years ago when I owned a 9C1, covering the external oil cooler made a difference. Deleting it made a bigger difference. Oil cooling seems unnecessary unless it's above 85°F and you sit around or stop & go a lot. Mobil1 0W40 or Castrol 0W30 are my preferences.

If the problem is your electric water pump, try a new or a different one. My Meziere HD never gave me any problems, except when it quit working. I changed it by myself on the shoulder in about fifteen minutes, and was back on the highway. Try that with a mechanical one.