Is it possible to have too low of engine temperature?

[GTSnake]

I installed the Roe 172 thermostat. It works like a charm. Running around all day the temp needle barely gets past the second from the left hash mark. I'm guessing that's the 172 degree mark.

The question that I have is: Is it possible to be running too cold? I know you have to reach a certain temp to burn off all the carbon and keep the combustion chamber clean. I have a Roe Blower with a 10lb pulley. I would think it would operate on the hotter side. Granted the weather around here has been in the 50's and 60's when I'm out driving. I guess I'll get a better idea when summer hits full swing.

 

[Marv S]

what's the temp when you are idling a while or in stop and go traffic vs cruising on the freeway?

 

[Chuck 98 RT/10]

I would say yes, running a motor too cool is probably not optimum. Plugs and timing were chosen for specific temps. I'm not sure how much it would hurt, I'm just saying it probably isn't the most efficient.

 

[GTSnake]

It's the same temp idling and driving. I haven't been in stop and go traffic since the change of thermostats.

The plugs are two steps colder than stock Iridiums.

 

[GR8_ASP]

Tom which iridiums did you choose. I have the Denso IK16

 

[Marv S]

Odd behavior. What did the gauge do before? Did you get all of the air purged out?

What happens after the t-stat is changed from the stock 190 to a 172 is it takes a bit longer to get to full operating temp (because the t-stat opens sooner) and water temp has big swings as it is now allowed to cool much more but will still go back up when the conditions merit it.

The gauge will really run low when crusing in 6th gear on the freeway.

It's when the motor is racing on the track, idling, freeway in 3rd or 4th, stop and go traffic, that it will run at higher temps.

If the motor wants to run at 210 degrees in traffic or on the track both the 172 and 190 t-stats are wide open and irrelevent to the motor temp.

The t-stat controls the low temp of the cooling system - not the high temp. That job is done by the heat exchanger and air flow through it.

 

[GR8_ASP]

Marv, I believe you assumed that the PCM fan turn on point was not changed and that the radiator is stock. I do not know that either is true but if so that would change the peak temp behavior.

As far as the temp staying low it can have bad effects. Fuel may accumulate in the oil more as the oil temperature will also run lower. Pistons may have been sized for higher operating temperatures and have different clearances than intended.

All - in - all I doubt it will be a serious impact given the lower mileage and better than average maintenance conditions.

 

[Toby]

When an engine is run below the normal operating temp range, the internal clearances are not what they should be. Pistons and rings are too loose for the cylinder walls. This is not a major problem for the brief time when a cold engine is warming up. If an engine is continually run cold there will be excessive clearances on a constant basis. Performance will drop and wear will be increased. There are other factors, too, like moisture in the crankcase not evaporating as quickly if the engine is kept cold.

My guess though is your gauge or temp sensor has gone wacky.

 

[Warfang]

An extreme example of this is the old Blackbird SR-71 recon plane. It was designed to leak fuel like a sieve when parked, but at speed and high altitude, the extreme heat sealed up the panels, stopping the leaks and it ran like a dream.

 

[GTSnake]

Tom which iridiums did you choose. I have the Denso IK16

I'm not sure. Ask Jeff Morys. He's the one that spec'd it.