SteveSP

Hi Guys,

I've got a '91 Non-turbo convertible which is running on the cold side. The needle barely gets off the "C" on the gauge. It started doing this after changing the coolant level sensor in the top radiator tank to fix the alarm sound it was making to indicate low coolant. Since then, it's been running cold. I've replaced the thermostat with a new dealer part. Also, this isn't a gauge problem because the engine temp actually feels as cold as the gauge is indicating. The fan clutch also seems like it's working properly and "freewheels" or is not engaging even after I've driven awhile and I shut down the engine. There's about a 50/50 mix of antifreeze/water in the cooling system and there doesn't seem to be any air in it. Anybody got any ideas? Thanks!

Steve Storey

WAYNE88N/A

Other than slightly less gas mileage, what's the problem with running too cold? The colder she runs, on average, the slower she'll wear. I'll get some arguments from that now, lol...

So you think the fan clutch is locked up???

Makes no sense that she should run cooler after replacing the level sender...

xtremeskier97

I wish mine always ran that cold!

Usually people have the OPPOSITE problem! LoL

88 GTU

mine runs very cold too and i've never had a problem with it

drunkin_idiot

why would you complain about running to cold. Its like everyones dream in these cars. Maybe by replacing that sensor it made a better seal therefore showing the full potential of ur radiator. Is it stock?

trent1059

After my rebuild and new radiator mine barely gets off the C, I expressed that concerns I have read here on the board to Chris at RX7.com(rotary performance of garland Texas) he told me that it would not hurt anything at all and in reality the colder the better, all that is really important is a constant steady temp, its more the flucuations, hot then cold that hurt your engine while running.

Don't worry about it...it's OK to run cooler.

VietFC

I dunno about running cold. I think you can actually hurt something if the motor isn't up to it's normal operating temperature. I think that if the coolant temps aren't high enough, and you decide to romp on it, the temperature differances between the coolant jackets and the combustion chambers might warp something. Why do you think people always say no more than 3,000 RPMs while warming up?

iceblue

NO! its not right. If you are running at any temp not at normal operating temp some thing is WRONG! Yes to cold is not good and to hot is not good. The whol point of a thermostat and yes even race cars use them is to regualte colling. The way it works is like a door or switch. the 1/2 of the water in the engin keeps the engin running at normal operating temp most engins is 200F wile the coolant in the RAD side is undergoing cooling process. If the car is or has ben running the engin water heats up to its max aloud temp by the thermostat after it surpasses that the thermostat opens and allows new cooled water from the RAD to enter. When enugh cool water has enterd to bring the car to normal operating temp the thermostat closes and awaits the next cycle. So somethign is wrong if you are on ither side of the guage.

Why not remove the thermostat? Well you can in a emergancy but your car will ushaly overheat. You will notice low cooling temp untill all the water eventchaly heats up and then keeps heating and no longet sufichantly cools the engin and then you begin to overheat!

WAYNE88N/A

The lower the average temps, the less wear that occurs due to heat-related friction. This applies to almost any engine that uses combustion for power, including jet engines (where no moving parts are actually touching each other). The important idea here is to maintain a constant temp between the rotor & side housings, because they are dissimilar metals and have different coefficients of expansion when heat energy is applied.

trochoid

iTrader: (6)

You said you replaced the thermostat at the same time. Occasionally they fail right out of the box, but usually on the hot side, instead of the cold. You might try testing the thermostat per the FSM and see if it is spec.

iceblue

The thermostat could be stuck open as well. A test to see is put it in boiling water and see if it opens up

NZConvertible

Engine oils are designed to work best (i.e. minimise friction) at the temps engine's normally run at (180-200degF). If the engine is colder than normal then the oil is not working as well as it should. This is why over half of engine wear takes place in the first ten minutes after a cold stat. Similarly if the engine is too hot the oil's abilities are lessened. The single biggest advantage of synthetic oils is they remain effective over a far wider temperature range, so your engine is better protected when it's outside it's normal operating temp range.

Do not ignore this problem, find the cause and fix it. Personally I would suspect the thermostat first, even though it's new. It's really the only thing that can cause overcooling because if it is working properly it will be closed when the engine temp is too cold. Pull it out and test it as per the FSM.

CompuBob

on cold days, mine never gets off the C (like in the negatives)
but on warm or hot days (it's beginning to get warm out) it gets to about half..
I'm about 99.9% sure my thermostat is dead, oh and the fact that I dont have a fan shroud, and my fan clutch I believe it dead also..

NZConvertible

Dude, fix your car...

NSBerkland

I had the exact same problem almost except it would just take me FOREVER to reach operating temp. Turns out my thermostat was partially stuck open when it should be fully closed. Now after replacing it with an OEM one (and replacing the waterpump housing and pump thanks to snapping a thermostat covering bolt) It warms up within 3 minutes :] almost brings a tear to my eye.