Overheating

[joechevy57]

Hello all, I am nearly finished with a 1950 Chevy 3100 pickup riding on a 77 model K10 4wd chassis with a 402 big block and automatic. I bought a Dessert Cooler from LMC and was told it would cool a big block. We took the truck on a 2hr road trip to Pigeon Forge, TN and it ran about 185-190 on the temp gauge. However, on the 2hr trip home it climbed as high as 210-215. I am running an electric pusher fan in front of the radiator with no mechanical fan. Most of the interstate trip was with the fan off but I did try turning it on some but it didn't seem to help at all while cruising at 60mph. My gauges are new from Classic Instruments with their sending units. The middle of the gauge reads 190 and the needle mostly stayed to the right of center on the way home meaning 210-215. Could the numbers on the gauge be wrong? Does anybody else have a big block with cooling problems? Took the truck out tonight around town and it never got over 195 by the gauge. Also added an aluminum overflow tank in the last few days and noticed tonight that it had dumped a small amount of coolant on the garage floor. How much heat is too much for a big block? My thermostat is a 180 best I remember. Any help???

[_Ogre]

running a 180* thermostat i'd expect to see 210* on a hot day, you have no problem
the thermostat is in there to maintain a minimum temp of 180*

the reason we use coolant and a pressure cap is to raise the boiling temperature
assuming your running a 50/50 mix and a 16 lb cap the coolant boiling temp is 276*

i suspect that the reason oem temp gauges have C to H and not 100* to 250*
is due to most motors running at 200* to 230* on a hot day

[Donaldo]

If the thermostat is wide open at 180'f., there is no restriction keeping the coolant in the radiator long enough to cool - so you will just keep adding to the higher temp the longer the engine runs. What is the optimal operating temp of the engine ?

[youngrodder]

Also if there is room, I would move the fan to the engine bay side (sucker fan). I heard/read that you lose something like 30% of your air flow using a pusher fan as a lot of the air flow is blocked by the fan itself. I had cooling issues and I switched to a Cooling Components fan which helped. http://www.coolingcomponentsinc.us.com/

The fans are very thin, quiet and moves some air. I had a cheap EBay fan on before, that went in the trash. The Cooling Components fans are not cheap but you get what you pay for. They are also a 2 speed fan.

Just my 2 cents.

Good luck
Marc

[OrrieG]

Living in West Texas and AZ for 8 years running at 210 or so was not uncommon, 230+ and I start getting a little nervous. Modern "gauges" are really idiot lights that move up to a point, say 160 then stay in the middle until say 230 or so then move to hot. I used to think my wifes Hondas had really consistent cooling systems because the gauge never moved, winter or summer, empty or loaded pulling a hill. Good news the current CRV has never moved past the middle.

[1project2many]

OEM electric cooling fans often don't turn on until 220+ so you're in a safe range.

[joechevy57]

Thanks for the help guys. Not sure what is optimum temp for a big block since this is my first rat motor. I thought when I bought this fan that it was a high cfm but of course the box is long gone. I will check out the Cooling Components fan, thanks again. This truck has an aftermarket A/C system but with the condensor mounted in front of the radiator it overheated immediately. I took it off until I could figure out how best to mount it.

[oossuuu754]

Just a thought, if the motor has been sitting for any length of time, probably wouldn't hurt to pull the drains on the block and check to make sure you aren't plugged. Just ran into this with my engine. Flushed the top of the block, put a new thermostat, new radiator, new fans and couldn't figure out why it was getting way hot and the coolant was so nasty with all the new parts. Pulled the drain plugs and not even a trickle, snaked the holes and got to see all the crap that had accumulated, most likely "Dirt Dobbers" and rat droppings"

[1project2many]

One thing to keep in mind: There are still more trucks with engine driven fans than with electric fans. At high load/high RPM the engine fan flat out moves more air. We often get away with the electrics in hotrods because they don't work like a truck, but it's good to consider how a truck's going to be used before committing to electric.

What's popular today is an electrically actuated fan clutch for the engine driven fan. Leave the fan disengaged until the A/C is turned on or until the engine temp reaches a minimum. That way you can save power like an electric but have max cooling when needed.

[joechevy57]

Both good ideas just don't think I have room for an engine driven fan.

[ssxty8]

In PR, I don't ever use antifreeze/coolant on any of my cars, due to the normal high ambient temps. Just the coolant part of a radiator additive, like Water Wetter, or Red Line. Never gonna see my rad water get freezed anyway. Water alone would be better, but I'd loose the rust protection. Make sure, or at least as much as possible, air is coming to the engine bay thru the radiator panel, not on holes on the side of the rad support, or even underneath or over the radiator(some cars even came with some kind of weatherstrip on top of the rad support for that reason), & check your ign. timing. You can even try a 1" hole on your thermostat. See pic.

[ssxty8]

I mean, 1/8" dia. hole.
Sorry.