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LT1 Coolant and Oil Temp changes


Joe Bob

Greetings, all! I am a rookie user here, having just registered but admit to have browsed this site for a couple of months now. I find you all to be very informative and have gained good information and technical advice from you.

To my question: Recently had some maintenance done on my 95 LT1 6-speed coupe (78000 miles). This included water pump replacement along with new 180F thermostat, distributor shaft seal, front crankshaft seal and intake gaskets. Prior to this work, coolant temp ran 184-187F, oil temp ran 197-205F. This in steady highway cruise, air temp 80-95F.

Post this work temps now are: coolant 197-205F, oil as high as 221F.

Chevy dealer which did this work has no explanation and has offered no suggestions as to cause.

Can anybody out there point me in the right direction to solution of this mystery?

Thanks in advance, Bob


Well-known member
Jun 3, 2002
Parrish, FL, USA
1992 LT1 White Conv.
My 92 ran 203-205 on the road. Don't remember oil temp. I put in a 160 thermo, now it runs 173-175. Thermo 20 less, but runs 30 less. Go figure.


Well-known member
Jul 18, 2001
Durham, NC
2002 Flat Black Z06
My92 LT1 runs 194-197 on the highway with same outdoor temps. In fact it runs like that almost all the time regardless of outdoor temp. Oil temp is about 210-220. It's been like that as long as I've owned the car. About 30K mi now. In town coolant will run up to 205 at low speeds. At idle in stop and go traffic forget it. It'll just get hot as can be until the fans kick on around 225. I just run the AC so the fan stays on and then it stays around 205.
This is no big surprise. These cars run really hot. GM says it's ok. But you'll notice many people swapping out the thermostat and going for a 160deg stat and possibly an aftermarket chip that turns the fans on sooner. That's what I'm doing right at the moment while flushing my system. I'm just taking a break while the car cools down...


YA! Iwould suggest the 160 stat, and a manual fan switch,easy hook up and works great, I dont even break the 178 mark even in the Hot desert,stop and go driving stays around 180-190,cant beat that.good luck.:beer

Joe Bob

Thnks to all for responding. It seems the temps I'm experiencing are normal for an unaltered system and I feel okay about that after reading the temps that you all see. I'm still wondering what caused the seemingly overnight change when I got the car back from the dealership.



Yes, these cars do run hot. I was very concerned about the temps I was seeing shortly after I bought my car until I did some homework on what is considered normal operating temps for the LT-1.

The ECM is set to kick on the fans at 228 degrees - and that is the factory setting. That seems a bit hot, but that is stock. From everything that I have read, it is normal for the LT-1 to run that hot. Many people don't like them to run up that high, and they go for the 160 thermostat and a different chip to turn the fans on sooner.

What you are seeing as far as temps. is normal - believe it or not.


Well-known member
Dec 5, 2001
Cross Roads, Texas, U.S.
'89 dk red coupe
I'd guess that what you had at 78,000 miles was a thermostat that was stuck open, so coolant temps ran lower than with the new new, nominally lower-temp 'stat.

I find it odd, though, that you had oil temps running 197-205, just an 8 degree range, when ambients ran 80 - 95, a 15 degree range. Every C4 I've seen has oil temp track ambient air temp almost exactly under any given load condition, i.e., for the same road speeds, with temperatures stabilized. That is, a 10 degree increase in ambient gets you a ten degree increase in oil temp.

You might be interested to read what my factory shop manual says on the subject of overheating: (paraphrasing from memory)
"If the customer complains of overheating while driving in parades, tell him that's not what the car was intended for!"


I agree with the others--
your stat was probably malfunctioning
before, those temps you speak of before
the work are way too cool for a stock set

I have had a hypertech chip for 3 years now,
and I change to a 160 stat for most of the
year (I go to the stock stat for winter).

With the chip, stock stat, car runs 200F coolant
210-215 oil.

With the 160 stat+hyper chip, it's 178 coolant,
190 oil--in the MD spring.

--I think I remember with the stock chip and stat
in winter it used to get to 195 oil on a 30 mi trip.

Joe Bob

I sure appreciate all the feedback I've gotten from everyone on this subject - it seems my car is running pretty normal for a stock setup. I have a 160 stat coming from TPiS - will give it a try and report back. Again, thanks all.


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