350 Typical Operating Temp

[ffdemoss]

Previous owner installed a rebuilt 350 and I replaced the radiator with a CJ 3-core aluminum conversion one and upgraded the fan to a Spal 16" puller with shroud. 180 degree thermostat. Idling, my truck runs about 185. After about 15 minutes of driving it climbs to 210 (running 50MPH). I haven't gotten more than about 15 minutes of driving because of the 210 temperature, but was wondering what others with a 350 are seeing. And if I park it and go back to idle, temp drops back to 185-190. Thanks.

[Von]

I was running about 210, creeping up to 220 at lights. Switched to an aluminum 3 row. Still a little high at 190ish on the road. At idle will creep up to 210. then higher if I don't move or shut it down after 5 minutes or so..
That's with ambient around 95.

It's a little better than it was but still a little too high. Don't know what thermostat it has in it. Suspecting I needed a different thermostat or my 3000 CFM fan isn't really 3000 CFM.

Seems like your temps are backwards... should be running cooler on the road with more airflow than just your fan.. ?

[md1970]

in all my sbc engines in the mid west I install a 180 thermostat, hotter than that its hard on cylinder heads as the castings are so thin they crack very easy

[Barrman]

My 396 did what your 350 is doing. Ok at idle but hot fast at speed. I tried Taurus twin electric fans, mechanical fans and a big 2 core aluminum radiator. The problem was still there.

I tried a 180 thermostat, a 165 thermostat and neither did good down the road. What finally worked was mechanical fan and a 195 thermostat. The only time it ever got over 200 from then on was during parades or climbing mountains above 10,000 feet.

Same radiator with the 6.2 and a 195 thermostat stays below 200 all the time.

[ffdemoss]

It's funny you mention the Taurus fans... Read about 5000 post on that last night. Since the thermostat is an easy change, might bump to a 195 and try that. That would allow more time for the water to cool in the radiator.

What type of shroud/mechanical fan did you end up with?

[ffdemoss]

I was running about 210, creeping up to 220 at lights. Switched to an aluminum 3 row. Still a little high at 190ish on the road. At idle will creep up to 210. then higher if I don't move or shut it down after 5 minutes or so..
That's with ambient around 95.

It's a little better than it was but still a little too high. Don't know what thermostat it has in it. Suspecting I needed a different thermostat or my 3000 CFM fan isn't really 3000 CFM.

Seems like your temps are backwards... should be running cooler on the road with more airflow than just your fan.. ?

I'm starting to wonder if the electric fan shroud I have is limiting air flow on the road and that's not part of my issue. Might be why mechanical fan might work better.

[Barrman]

Fan theory gets interesting and confusing. The theory is that a properly working cooling system doesn't need a fan above 30-35 mph.

I had my fans on a switch with the 396. I could turn them off above 30 mph if the outside temp was below 80° and I was on level ground. Otherwise, nothing kept the temperature down on the engine. I swapped radiators and it was a bit better. Changing thermostats made the biggest difference.

Then I had charging issues with the fans turning all the time in stop and go driving with lots of engine starts. Basically, running errands on hot days became something I avoided.

I went clutch free mechanical to make the charging thing better. I didn't have a shroud then. As mentioned above, only parades where I didn't run in low range to keep the rpms up or climbing mountains at the 2008 FE in Beuna Vista, CO got me over 200° from then on.

I had a complete 6.2 diesel from a M1009 with the factory clutch and fan. That set up works great in the 3 square body trucks, so I used it in the M715. I built a shroud out of plate steel and part of a metal 1960 Chevy truck shroud.

I built it with less than 1/4" clearance. I was going for the ducted fan approach. No matter what I have been doing, 3 minutes at idle and it is below thermostat temperature. However, the engine moves around a bit and the fan hits the shroud. Mostly on clutch release with a trailer, backing up a trailer and frame twisting off road uses. I have been making cuts and peeling the shroud back a bit at a time over the last 2 years. One of these days I will get no more hitting and then weld all the cuts backup.

Pictures are in my 6.2 install thread.

[kwai]

I have a 350 in my truck. When I got it, it had a flex-a-lite electric fan. I never liked it because it was very noisy. It also didn't cool well on the road. It could keep up at idle but the temp would go from 200 to 220+ on the highway when the outside temps were 95+ (typical Houston summer). The truck has a wagoneer-size 2-row radiator.

I think the problem was that the fan and shroud was actually restricting air flow at highway speeds.

I replaced it with a jeep wagoneer HD fan (7-blade) with a new clutch and have never put a shroud on it with a 190 degF thermostat. It is much quieter and keeps the truck temp at idle and on the highway even at 100+ degree road temps. I haven't seen it get over 200 even on the hottest days in bumper-to-bumper traffic.

I really like the jeep wagoneer HD fan because it moves a lot of air. At idle, you can actually feel the air flow in the wheel wells.

I am sure that if had a shroud it would do much better.

[md1970]

you cant give me a elect. fan for any app.m

[Von]

you cant give me a elect. fan for any app.m

I've always heard they were better.... but after this thread I'm rethinking my cooling system. Going shopping for a fan today.