Little Red L98

I have a 1989 L98, bone stock, 58K miles. During the summer months it was running between 200-220 degrees, oil temp about the same. Now that the weather's cooler, its running around 192. I've seen posts where folks have 160 or 180 t-stats. Not sure exactly what I've got, but I'm wondering if I should run a lower t-stat. Should I be worried about consistently running 200+ degrees (when it's warmer). Is this too hard on an older motor? I've only owned it since this June, but it's been lovingly taken care of by the PO, and I plan to keep it that way. Appreciate your expert advice and comments. Cheers!

gerardvg

The temps are pretty standard, the ecm will turn on the cooling fan when around 230f or when the a/c is on via a high side pressure switch. I think 190f thermostat is standard hence running around 190 on cooler days. The higher engine temp is for emissions they won't have any issues running at 220-240f as long as your coolant is the correct concentration.

Also a hotter thermo stat gives your radiator more tie to cool the water before it opens again, hence when you have no t/stat some cars tend to overheat in summer.

Think of it like a pot of water on a stove, when on a constant flame even if its not on full will eventually boil but taking the pot of the flame for a bit every once in a while will keep it from boiling.

You can get away with a cooler t/stat and after market chip to turn your fan on earlier, depending on how hot it gets outside and how much you use the a/c.

If you need to pass emissions keep the stock t/stat, it also makes the heater work quicker.

Sweet 90

Why do you think putting a lower T-Stat in will lower you operating temperature?

gerardvg

Unless you get an aftermarket chip that will enable the ecm to turn the cooling fan on to maintain the lower temp, it will still stay up around 230f unless on a highway with constant airflow thru the radiator. Standard the ecm wont run the fan above a certain speed, so a 160f or 180f t/stat will be fully open most of the time.

I actually have a 190f t/stat in my vette but with aftermarket fan controller that keeps it around 190f all the time. However my vette is not standard and it needs the hotter t/stat to enable the radiator time to cool the water with the intercooler and a/c reducing the radiators capacity to keep her cool.

383vett

To the op, everything seems to be in order. The car has been running this way for over 20 years. No need to change. Enjoy the car.

Little Red L98

Good point about the heater warming quicker. Though not a daily driver per se, I do plan on driving year round as long as the roads are dry. I usually get by without a/c in the summer unless the Mrs. is along for the ride (go figure ). Maybe a little irrational, but I guess I get a little paranoid when the temp goes above the boiling point of straight water. I appreciate the assurance that everything's AOK.

Don't remember what the temp was sitting in gridlock on I-95 on this particularly hot summer day (no a/c running).

1993C4LT1

Not sure it's the same since I have the LT1, but I turn the ac on and it runs from 190-205 in city streets.

Old Ben

Same here. High around 215 stopped in traffic.

65Z01

Indeed your L98 is running in the stock temp range, so there is nothing to worry about in that area.

My "new" '88 ran just above 200deg F all summer; now with the 160deg T-stat she stays at 158deg that I prefer. There are two advantages of this: 1) a little more HP, 2) the EGR system will not open and dump exhaust gas back into the intake until coolant temp is >175deg F in steady state (highway) driving.

Indeed it will take a chip burn of a manual fan switch to maintain my 158deg coolant temp in city driving. At the strip, with my prior '88, I simply opened the connector in the A/C pressure line to bring on the coolant fan but hesitate to do that for street driving.

After I installed the 160deg T-stat in my prior '88 and cleaned the intake base, runners, plenum & TB they remained clean for >12yrs of driving due to the absence of exhaust gas mixing with intake air. BTW, the valve train also looked very bright & clean after operating at those lower engine temps. Also, it easily passed the OH e-check exhaust gas sniffer test every 2 years while running at the lower temps.

Sooo, it's your choice to lower operating temp or not.

itsmejimr

My '89 use to run in that 220-225 range. You can change out temerature sensor(drivers side of the block). Pick one up from either Summit or Jags, about $20.00 and 5 mins. of your time. It turns on the main fan(but not the pusher fan) at 190. Now I average between 183 but never over 195 even in stop and go traffic. I believe there is also one rated about 205 or somewhere in that range.

Little Red L98

Might try the temperature sensor. Sounds like a simple enough solution. Even though there's no apparent problem running @ 220+, the lower operating temp over the long term would bring me peace of mind. So thanks!

itsmejimr

I think the term "long run" is the key. Unless it is affecting the performance or the on board is trying to make adjustments, 190-200 is plenty warm enough. Has had no adverse effests on my performance.