I'm on a vacation road trip and noticed something yesterday that I hadn't seen before, concerning the digital (not merely the analog) coolant gauge.

I check my gauges periodically, and at home, in Austin, Texas, for the past 2 1/2 months I have owned my 1992 LT1 convertible with auto transmission, I got used to seeing the digital coolant gauge varying only between 193 and 210 normally,with most of the time spent around 205. That didn't surprise me given our daily Austin highs of 95 to 107 degrees.

But, on this trip to Colorado, I have seen something a bit different.

First, yesterday, on I-25 between Colorado Springs and Denver, I got caught in a traffic jam due to road construction, that lasted for several miles, with average speed maybe walking speed, and some outright stoppage periods. I watched the gauge climb from 195 past 200, then past 210, and just short of 220 when I was finally able to get moving at 30 mph or so, and then the temperature fell down to 215, then 210, and finally 205. Ambient temperature was in the high 80s or low 90s.

Last evening, I went for a short (2 or 3 mile) drive in a hilly residential area (looking for a way out to a commercial area), at maybe 20 mph, and watched the temperature again hit 215. Ambient temperature was still in the 80s.

Then this morning, with the temperature in the 70s, I climbed from about 5300 feet elevation to 8000 or so, via a hilly and winding canyon road, with an average speed of 35 to no higher than 40. The digital gauge started in the 190s and climbed over the course of the maybe 30 minute drive to as high as 215. Then, as I came over the "top" of the canyon pass, and started downward, the digital gauge started dropping again, and ultimately returned to it normal fluctuation range of 195 to 210.

Now I recall that my 2002 Z06 with its 405 hp LS6 DID frequently exhibit coolant temperatures as high as 228 degrees in stop and go traffic, but that was a much more powerful engine.

Is this all normal behavior for an LT1 C4?

At what temperature is the radiator fan supposed to come on? (I don't think I ever heard it, but maybe I just don't hear that well)

Is the thermostat and radiator combination incapable of keeping the engine at a more stable operating temperature?

Jim G

 

very normal your rad fans dont kick on till around 240. But at a stedy cruise your temp should run close to your thermostat setting

 

The fan kicks in at 240? What is the boiling point of the proper coolant solution in these cars?

Jim G

 

Your temps are normal. Boiling point with a 15# pressure cap is about 260.

Some interesting reading: http://www.theherd.com/articles/lt1_cool.html

 

Thanks, Seabright! That article looks like it is full of good information. I'll read it tonight. Just oin quickly scanning it, it looks like the primary (RH) fan kicks on at 229, which would explain why I didn't hear anything at under 220.

Jim G

 

I don't like those temps, at which the either fan turns on. I just turn the ac on because both fans are on at that point.

 

You need to have the car trailered home where you can put an LS1 engine in it!

OK, I couldn't resist throwing that out there. I've been reading the forums all afternoon and according to some, that seems to be the common cure for everything from broken headlight motors to bad wheel bearings.

Your temps sound normal to me for an LT1. As someone else mentioned, the fan comes on at 228°F. If you turn on the A/C that will force the fans on and tend to minimize coolant temp variations.

 

jim; if you haven't ever had your car at higher altitude, then you can expect a vehicle to run hotter.

most vehicles cope and you don't notice. our cars are, in my opinion, are sold of edge of staying at proper operation temp.

the air is thinner and it takes more surface area to cool than at lower elevations.

i was up on monarch pass a month ago and got the old 84 up to 250 and the red warning light in the gauge (didn't know it was there) came on

i have added a double pass new radiator to help mine. if this is your only visit you will likely get by fine. but if your moving to here from, texas a more permanent solution might be considered.
enjoy colorado.
gary

 

Most owners would be more than happy with those numbers under those conditions

The C4 owners who panic when their engine goes over 200F are usually coming from a old skool SBC where 190F
was stop the car and panic material.
The world has moved on since those days

 

Ok, thanks for the reassurances. I was not used to this!

Jim G

 

Seems like normal running temp. Fan kicks in at around 229-230. Mine used to get to 230 in traffic then slowly come down to 198-200. My C6 runs at 198 and gets as high as 215 in traffic. Vettes love running hot and I've learned not to sweat it any more.

 

[QUOTESeems like normal running temp. Fan kicks in at around 229-230. Mine used to get to 230 in traffic then slowly come down to 198-200. My C6 runs at 198 and gets as high as 215 in traffic. Vettes love running hot and I've learned not to sweat it any more. ][/QUOTE]

Just the nature of the beast!

 

No
The temp it was engineered to run at by the factory for emission and fuel economy reasons.

 

The fuel economy thing is working.

My 1992 came with an EPA hwy rating of 24 mpg.

I changed the gearing from 2.73 to 3.54, which is 30% higher engine rpm (2000 rpm in OD at 60 mph), and am STILL getting 21.0 at 74 mph, 22.3 at 60 mph, and after playing in the mountains in Colorado on my vacation today, at altitudes ranging from 5300 to 8300 feet, up and down repeatedly, and then a bunch of suburban driving, and then 24 miles of pure city stop and go, after 156 total miles I STILL averaged 19.7 mpg.

Not bad.

Jim G

 

Forget about the miles-per-gallon, and enjoy the ride.

 

Thanks for the link to the article. It's good to have on hand.