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Hello guys, i have been dealing with an overheating issue in my 59 Apache with 283. I am in Houston and it can get really hot at times. I have changed stat to 160, I have added a shroud which has helped a lot in slowing up the truck from heating up but hasn't stopped it. I have flushed radiator with flush product and have even used that "stay cooler additive." I do not have an electric fan and really dont want to get one if i can keep my manual one. The only time that it gets hot is when im at idle, as soon as I get moving its fine so I know its lack of cooling air due to slow idle speed of fan blades when idling. Now my question is this what exactly can a fan clutch due for me? Could this be what I need? Next question is should I get a severe thermal fan clutch or does it matter? Any help is greatly appreciated.

I don't think a clutch would do anything for you, they're really meant to 'release' the fan when it's not needed, won't change anything at idle unless you can find one that spins faster than the water pump, and you could do similar by changing pulley sizes, which may be part of the problem if there actually is a problem .... also a thermostat sets the minimum temp for coolant flow, has nothing to do with maximum temp, a 180 would be better for engine life and make no difference for overheating .... make sure, using a good laser thermometer, that the truck is really as hot as it seems, don't depend on the gauge .... if you see you'll have to sit so long it'll heat excessively, shut it off!! I always do that in traffic jams or drive thrus - saves gas too boot

also do NOT overfill the rad - some folks think coolant pushed out indicates overheating, but more commonly it indicates you put too much in, need to leave it a couple inches down to allow for expansion unless you've added an overflow bottle setup

Bill

ok thanks on the clutch issue, but for example 2 weeks ago we were in Austin at a carshow, the streets were packed after the show really no chance to turn off cause you would crawl every 5 seconds and it was tensful trying to figure out how to get out of the traffic jam, just wish i didnt have to deal with all that. I will change thermo back to 180, i just got the shroud and it seems as though it helped some but not completly, is it possible that I can get an electric fan to fit inside the existing shroud. I'd hate to have to replace the $90 shroud I just got from LMC. Any suggestions?

You might find a fan blade with more blades on it or more pitch. The flexblades work good if you get a good brand. A cheapy can throw a blade & do serious damage. Or if you run high RPM you wouldn't want to use one. I don't like fan clutches. The after market ones are not good. Some guys put an electric fan in front of the radiator with a manual switch. The position of the fan in the shroud can make a differtence also.

I will search the flex blades. Just seems as though my blades aren't moving fast enough to circulate anything on idle. Is the electric fan the best way to increase the spped of blades at idle?

yes, as George says, the position of the fan in the shroud is important - those plastic shrouds don't necessarily wind up right, it's important that the length of the fan blades fill the shroud opening with minimal clearance, and that the fan [or shroud] is positioned so the center of the blades is at the opening, must not be inside or outside the shroud - this is one I put on a buddies 56, works fine - on my 58, with a factory shroud from a 60's car, I had to add a spacer behind the fan, that actually put it too far in, but it works fine so I haven't bothered looking for a shorter one .... speed up the fan by getting a smaller pulley on one position for a shorter belt, but you shouldn't need to do that using standard stock stuff

Bill

yup fan is set exactly as your first example there squeeze, my next step is elctric fan main question is does anyone know where I can pick one up that is not shrouded already to so I dont waste money on the shroud I had recently purchased for truck. Ive been told Oreilly's sells one any other suggestions?

might try a pusher

Bill

My trucks previous owner lost a fan blade while giving the engine some gas too pull away from the lights, It punched its way through the hood with no trouble at all. Makes me very consious when leaning over the engine , and now allways stand too the side when the Engines running

I have a " Flexalite " pusher fan on my '40 that works well in warm weather. I have it hooked up to a thermostat switch which comes on @ 190 F. Bolts thru the rad on the front side so should not affect your shroud. Most Hot Rod shops will have this or similar product, or try Summit / Jegs ?

What size fan do you have? they make three sizes that I know of 4 blade - 6 blade , & 7 blade. Maybe one with more blades is in order.

Mine is a 1250 cfm - about 13" diameter - think it has 8 blades. I think you can get a 2500 cfm model as well if you really want to move a lot of air. Have a look at Flexalite on line for details.

I experienced the exact same syptoms in my '49 GMC 1 Ton w/248, I changed the water pump, no change, I replaced the 4 blade fan with a 5 blade, no change, I had the radiator re-cored with a 4 row tube core, still warms up when it sits at an idle after normal driving. If I rev it up to about 1,000 RPM while stopped, it maintains a lower temperature. It doesn't overheat, and I have concluded that it is a result of reduced coolant flow through the engine at idle speed. I tried letting it idle when I got home one day, it warmed to 195 degrees as usuall when I stopped moving, and after about 10 mins was back down to 180 degrees and stayed there on a 110 degree afternoon, I'm not going to worry about it anymore.

How hot is it actually getting? How long does it take to heat up? How fast is your engine idling?

I assume you have resolved your overheating issue by now. However, in case you still have overheating issues when idling in traffic on a hot day, I will explain an identical situation that I finally resolved. I performed a leakdown test on each cylinder and when I put air into cylinder 6, I heard gurgling in the radiator. I suspected a blown head gasket but when I removed the head the gasket was fine. I put the head on my workbench and using a magnafying glass found a small crack about an inch long that started from the exhaust valve seat. This overheating issue had gone on for about a year and I never got water in the oil and never had a radiator leak. As long as I was not stuck in traffic on a hot day, the truck had normal temperature.I relaced the head and the problem is fixed. My engine is a 283 V8. Hope this helps.

Very interesting Bud. Been suffering all the same symptoms. Re-cored 4 row fin tube radiator (original tanks), flushed system, new water pump, NO thermostat, electric pusher 2000cfm fan. Maybe not as bad as some, and was indeed hot here in Houstom (several weeks of 105-110), but idling in traffic was very difficult to keep from boiling over (due to thin original tanks only running a 3psi cap). Even today with temps in low 80's hard to idle, even with A/C off. Been jacking with timing and that has affected it and I still have work to do on that before before I do a leakdown as you suggest.

The engine supposedly had good and consistent compression test (165-170psi) when I bought it. What exactly did you do for your leakdown test - initial pressure, time and leak down rate, etc.?

Thanks for reviving this thread.

I was actually installing the rubber umbrella type valve guide seals to stop oil leaking down the valve guides. In order to install the valve seals, the engine should be rotated until both valves close on the cylinder and then air is pumped into the cylinder using a leak down adapter in place of the spark plug. This prevents the valves falling into the cylinder when removing the valve springs to insert the rubber seals ocer the valve stems. I just happened to hear the gurging noise which evetually started pushing water out of the radiator. So I just lucked out on my discovery of the stress crack on cyl 6.

As a side note, I had a similiar problem with a 1966 Cougar on a trip to Florida a long time ago. When cruising the streets of Ft. Lauderdale during spring barke, the Cougar started overheating. I took the car to a radiator shop and they found carbon monoxide in the coolant. In that case it turn out to be a blown head gasket. Here is a link that explains the procedure for checking for head/head gasket issues.

http://repairpal.com/how-to-test-for-head-gasket-failure

BudJ

There is an and electric fan on the V-6 Tarus and one on the Grand Cherokee, both from the '90s, that are around 2000cfm and can be made to work fairly easily. Either one should keep your engine cool, even in traffic. I would look for some other reason for the "hot running." BTW, did you get all the air out of your cooling system the last time you had it open?

best wishes,

Les