Cold Weather - Coolant Temperature

snider · 12-20-05, 11:50 AM

Hi folks -

I have a quick question regarding my '98 C5 6-speed with regards to cold weather driving.

I live in Saint Louis, MO and the outside temperature has recently been in the low 20's. I've noticed that my coolant temperature tends to run pretty cool - in the 120-130 range. If I park it and let the engine idle, it will come up to ~200 and cycle nicely... But as soon as I hit the open road, it starts to cool down. At interstate speeds it stabilizes back in the 120-130 range.

Is this normal? Or should I start thinking about the possibility of having a "stuck open" thermostat? Also - is it bad for the car to run it like this? (I have no faults on the DIC and the car seems to run just fine).

Any advice or suggestions would be welcome.

thanks, Sean

DRTH VTR · 12-20-05, 01:32 PM

Quote:

Originally Posted by snider

Or should I start thinking about the possibility of having a "stuck open" thermostat? Also - is it bad for the car to run it like this? (I have no faults on the DIC and the car seems to run just fine).

I would suspect the thermostat.

There are lots of opinions about what is the best temperature for engine operation. I think that the LS engines were designed to operate at water temperatures greater than 200 degrees. Emissions may suffer and piston/cylinder tolerances may be affected.

12-20-05, 01:53 PM

Quote:

Originally Posted by snider

Hi folks -

I have a quick question regarding my '98 C5 6-speed with regards to cold weather driving.

I live in Saint Louis, MO and the outside temperature has recently been in the low 20's. I've noticed that my coolant temperature tends to run pretty cool - in the 120-130 range. If I park it and let the engine idle, it will come up to ~200 and cycle nicely... But as soon as I hit the open road, it starts to cool down. At interstate speeds it stabilizes back in the 120-130 range.

Is this normal? Or should I start thinking about the possibility of having a "stuck open" thermostat? Also - is it bad for the car to run it like this? (I have no faults on the DIC and the car seems to run just fine).

Any advice or suggestions would be welcome.

thanks, Sean

Snider,

I also live in Missouri and have been living with this cold weather. I have a 99 M6 coupe and my tempature always stays at 190 even in this cold weather. I think DRTH VTR is right on the money with the thermostat opinion. Good luck figuring out this problem.

snider · 12-20-05, 01:59 PM

Thanks for the information! I will check the thermostat. Any advice on troubleshooting? Or tips for replacing? I'm hoping that it is something I can do myself.

Thanks again,
Sean

PreacherNutshot · 12-20-05, 04:10 PM

Make that 3 votes for a stuck thermostat.

BTW: I'm in Columbia, Missouri and I've been running @ 190 even when we were in single digits.

vett boy · 12-20-05, 05:53 PM

#4 here.

vette747 · 12-20-05, 07:40 PM

#5 here.

snider · 12-21-05, 09:46 AM

I plan to replace the thermostat myself with a stock OEM part. Can anyone provide a bit of guidance about how to actually perform the replacement? I am fairly mechanically inclined and have worked on many (other) cars, but this will (almost) be the first time I've had the hood open on my Corvette for anything other then washer fluid addition or air filter replacement. Also - should I check anything else out while I'm under the hood? (the car is 100% stock, has ~45K miles, and runs like a dream)

Again, thanks in advance. This forum is a great source of information/guidance and there seem to be many helpful, dedicated folks around here.

- Sean

c4c5specialist · 12-21-05, 10:31 AM

Hi there,
You will need to drain the cooling system.
Then, you will need a 10mm socket to remove the thermostat housing, located on the passenger side of the engine, where the large hose connects.
Once removed, you can replace the housing and torque the bolts to 89 in lbs.
Remove the hose that is connected to the throttle body, either one will do.
Fill with a 50/50 mix of Dexcool and distilled water, till it dribbles out of the hose. Reconnect the hose and start the engine.
Recheck your level after the engine is at operating temperature, and you are done.
You may have to top off a little the next morning, but that is not uncommon.
Allthebest, c4c5