So today, of all days, I decide to use the air for the first time in the heat of Dallas. It was about 100º at the time.

On my short 5 mile drive the engine read 220º by the time I got home.

I know it was hot outside but I didn't figure the engine would get that hot.

Any ideas as to what I should look at or do you think it was the result of the temperature outside?

John 8)

I have a 86 here in Oklahoma. We have had a week of 100 degree days. The old original 2 core radiator was replaced years ago. The replacement was a cheap P.O.S. that I fought with for years. It never went more than a month without a leak. After several years of cussing it I finally just bought a new high quality 3 core radiator. Now my engine stays at 195 to 205 degrees max. The A/C blows nice cold air and the fan almost never goes into lockup.

If you have any questions about the old radiator replace it. With my old radiator I was at 220 a lot and the fan was in lockup even while driving down the highway. That never happens now.

I'll second that.. if you're even a little suspicous of that radiator, replace it.

I finally, after years of moderate overheating in slow traffic (moderately built 350, headers etc, fixed hi-capacity fan, old radiator, no AC) just recently ripped a Modine 951 aluminum radiator out of a junk '89 Firebird:
http://elcaminocentral.com/modules.php?name=Forums&file=viewtopic&t=11869

The thing now never cracks 190, and this is in hot beltway traffic here in DC with a 650rpm idle... i'm going to go the rest of the route and put the electric fan and full serpentine setup on there this weekend.

(i can't *wait* to have AC in the car again!)

PS: i've heard that the M 951 is about $140 new from autozone. Ask for a radiator for a '91 Camaro w/ 5.7L. OTOH, i got mine plus the whole serpentine system and everything it touches for $80... ymmv

I would say the 100* temp was the culprit.

Mine would do worse than that on hot days and/or in stop and go traffic. I went to an aluminum radiator and added a couple of Taurus electric fans as pushers in front of the radiator. It will still climb up to 210 in stop and go traffic with the ac on when the outside temp gets near 100.

My OEM guage reads 220 all the time. But I checked it against a mechanical guage a few years back. The mechanical guage read 190 - 200 depending on the driving situation. I have run an 89 Caprice radiator for several years now. It's an aluminum single row and bolts right in. Never had a boil-out, never had to worry about it. It was 102 here in NC today. The dash guage read 220 as usual. :)

Hello John,

Areas you've likely already addressed as knowledgeable as you are:

1. By any chance, are you running a 305 or a 350 size radiator with that 454? You wouldn't be the first.

2. Do you have mods on your BB generating more heat that on an normal day wouldn't be noticed with a "stock" cooling system? Do you need the bigger radiator, high volume pump, etc.?

3. Are you running electric radiator fans? What is your fan set-up? This is often an overlooked culprit.

I've kinda been looking for an excuse to drain my antifreeze and run one of water wetter products to see how well they work. I've heard nothing but good things from users and 10 degrees can be significant when you live in a microwave.

I won't insult by asking about thermostats and some other basic stuff. You ain't no rookie.

Take care.