Overcooling Does Exist!

[enaberif]

You know you always hear those "stories" about people overcooling their vehicles and think to yourself nah ... no way!!! Dudes full of crap.

Let me tell you I can't be a naysayer anymore!!!!!

So I went to Canadian Tire and picked up a infrared thermometer because I was simply curious of what the temps were of things when they were running. The truck gets up to temp and I check the temp at the water pump where its entering the block...

180* F

So then I put the gun on the base of the waterneck..

170* F

I am showing a 10 degree difference between the water neck and the water pump... So I check the temp of the radiator ... 41* F. Hmmmm I go this can't be right can it?

So go into the shop grab a couple of tools and pull the fan off the truck and run straight pulley no fan. Start the truck again and let get running and now I put my gun on the water pump at the head again..

190* F

I jumped 10 degrees by removing the fan!! I'm thinking hmm really? So I let the truck run some more and then I check the pump at the head..

205* F

Well now I'm shocked! So I put the gun at the base of the water neck..

195* F

Look into the radiator and the coolant is bubbling and I can actually see the coolant flowing like its supposed!!! Succcesss!! Water pump is pumping.. thermostat is opening.

So guys.... Yes you can simply overcool your vehicle based off the fan you are running!!!

So this weekend off to PnP to pick up a clutch fan.

[SkinnyG]

Interesting find!

When I built my motor, I switched to dual electric fan and shroud from a Windstar. I used a solenoid off a Cavalier (recall unit for starter), and a thermostatic switch out of a FWD 2.8L V6 GM somethinorother, and it works great!

Though I think it might still run too cold while I'm moving....

[enaberif]

Originally Posted by SkinnyG

Interesting find!

When I built my motor, I switched to dual electric fan and shroud from a Windstar. I used a solenoid off a Cavalier (recall unit for starter), and a thermostatic switch out of a FWD 2.8L V6 GM somethinorother, and it works great!

Though I think it might still run too cold while I'm moving....

What started this whole escapade was that when I would fill the rad and put the cap on and shut the truck off after a few minutes you could hear the coolant rushing out. I was always filling the radiator back up with exactly the same amount of coolant.

So I replaced the thermostat with a 195 vs a 180 and still had the same issue. I was reading and people were saying that you can tell if your water pump is working as you can the coolant pouring back into the radiator which I did not see. So this is when I picked up the temp gun to verify what I was thinking as I was told that the upper rad hose can get warm without the thermostat opening due to steam and or residual heat.

Now without the fan everything works as intended and makes me wonder if any of this was working properly before I did the rebuild on the truck.

PS.... The fan in question is the one on the left with the flat rivets. Apparently using this with my truck now is a no no so I will have to pick up a clutch fan to use instead.

http://s270.photobucket.com/user/jon...2/018.jpg.html

[MikeB]

Over-cooling can also occur with a 160 degree t-stat on a cold day. Actually, I've read that anything below around 190 will let moisture collect in the crankcase.

[rich weyand]

I could never get decent heat in the truck in the winter, and the operating temp was all over the place depending on outside temperature. So I took the fan and shroud off and mounted a Flexalite 15" fan in front of the radiator on some bracketry I made. I used the Flexalite controller with one of those capillary sensors in the radiator.

Now I know that mounting an unshrouded fan in front of the radiator is not as efficient as running a shrouded fan behind, but cooling efficiency was not a problem.

As it is, the fan doesn't turn on much unless I am idling, then it will cycle on for about 10 seconds every minute.

Here's the install details, on another forum.
http://forum.73-87chevytrucks.com/sm...?topic=27899.0