Engine runs kind of cold - worry?

[monkeyodeath]

My temp gauge never gets above slightly beyond halfway, and that's idling on a hot day.

But when I'm on the freeway, the temp drops to slightly below the 1/4 line. It happens pretty quickly. It doesn't get into the blue temp area, though.

The car warms up pretty quickly, and the water pump and thermostat are both new, so I don't feel like the thermostat is stuck open.

Is this worth worrying about? The user manual says anything that isn't in the blue or the red is fine. But I know others seem to have less temperature variance than I do.

[LJ851]

Your car should quickly heat up to 1/2 way on the gauge and stay there idling, driving, whatever.

[monkeyodeath]

So I guess either I got a bad thermostat or my fan clutch is stuck.

[accident]

It really does sound like your thermostat is stuck open, but maybe try installing one with a higher opening temperature.

[LJ851]

It's not your fan clutch, once you are above 35mph or so the air getting forced through the radiator is more powerful than any fan. The thermostat is the main component that ensures the temp does not go below a certain level and is a good place to start. Are you sure it was installed correctly(not backwards)?

[blefevre]

Mine only gets to half way if I am idling in 100 degree weather. All other conditions it stays just above the 1/4 mark. I've had two different thermostats in it with no change. I don't think much of it.

[delatlanta1281]

Each operating temp is different for every car. Remember, these are old cars, none of them will run the same, or have modern style electronics (IE VWs all run at the same operating temp). What we have found in my group is this. Cheap WP = higher running temps. BMW WP = lower running temps. My car used to run at halfway mark no matter what with a World Pak WP. When I did the timing belt and replaced the WP with A dealer one, it now runs at 1/3 rd. If your heat works, and your car doesn't overheat, I can't see any problems. M20s get up to operating temp pretty quickly no matter what. Mine is up to operating temp in @ 5 minutes of driving.

[Jafxod]

I consider my m50 car to be overheating when it hits halfway haha. Just be happy your running cold and not hot.

[monkeyodeath]

Yeah, the heater actually works fine. Water pump was replaced with a Graf unit. I may check thermostat again to see if it's not stuck open, but I'm 99% confident I installed it the correct way.

[monkeyodeath]

I was nervous also about the variance I'm seeing on the gauge.

When I'm driving on the street, my temp will be a bit above 1/4. Jump on the freeway, and within a minute it's down to below 1/4. Idling for a while, it rises to a bit below 1/2. The highest I've seen it was slightly above 1/2, on a 100+ degree day, idling for 15-20 minutes.

[acolella76]

i had an OEM water pump and 80˚C thermostat and 'operating temp' was a little below the halfway point. I put in a Graf water pump and 76˚C thermostat (it was an accident, i thought it was 80) and operating temp is literally the same spot. It's nothing I would be worried about.

[delatlanta1281]

I was nervous also about the variance I'm seeing on the gauge.

When I'm driving on the street, my temp will be a bit above 1/4. Jump on the freeway, and within a minute it's down to below 1/4. Idling for a while, it rises to a bit below 1/2. The highest I've seen it was slightly above 1/2, on a 100+ degree day, idling for 15-20 minutes.

Sounds exactly like my car. I wouldn't sweat it.

[Eecen]

You guys sure you're putting the right thermostat in?

My m42 used to sit well below half, and never got to half unless I was in stop and go traffic on a hot summer day. Then I changed the WP and put in the right temp T-stat (old one was too low) and it was steady 1/2 at all times.



On a side note my E21 has a crazy temp gauge. Goes past 1/2 in stop and go on hot days, and stays below 1/2 while going 60+kph. Good thing idgaf about an M10.

[BergerNJ]

Like said above.....our cars at the least are 19 years old and will not run the same.....so everyones car wil eventually some where or somehow run differently

[rodpaine]

Borrow an infrared temp guage and determine what the temp actually is, at the point on the upper radiator hose shown below!