I've always taken the cooling system for granted in all my years of helping my dad and granddad work on cars and trucks. Now that both of them are gone, I'm not sure I know the why's, how's and what if's of it! I thought I did until last night! Let me set the stage! 1950 1/2 ton PU w/ a '62 235 motor. The motor is completely rebuilt, standard bore, stock Rotten-chester 1 bbl, manual choke. "New" radiator from Jim Carter, "new" short shaft water pump. During initial shake down run, I noticed a trickle of anti-freeze coming out of the overflow. No big deal, I think, probably over-filled the radiator and it is seeking its optimal level. BTW, I'm running a 185 degree thermostat and a 7# radiator cap. Back to the story. Several short, but very pleasurable drives later, temp gauge always on 180-185, last Sunday, it stopped trickling and decided to puke boiling anti-freeze in the garage, about the size of a frisbee. I didn't think much about it but decided to check the radiator last night, and SOB, I could not see any anti-freeze at all. Long story short, I've been fretting over this all night long! OK guys, I need help! I've got several questions. #1. What thermostat should I be running, given the Texas heat? #2. What should I be running on the radiator cap, 0, 3, or 7? #3. When I refill the radiator, how far below the top of the radiator should I fill it? Any other thoughts, suggestions or game plans are very much apprecriated! Ken
Similar issue Ken - I have noticed similar issues with my ride. I ran a hose from the overflow into a "tank" (an empty Prestone jug with a 3/8" hole drilled into the cap will fit nicely on the drip pan behind the grille and in front of the radiator). What has puzzled me is that sometimes the tank is full and sometimes empty. The fluid in the radiator seems to be low when I check it cold, almost nothing showing in the upper part of the radiator, but I'm no longer leaving a puddle and haven't overheated. They sell a period correct tank, if it a tank solves your problem...
Ken - Instead of a Prestone jug, use something that you are more likely to have around, like an empty Jack Daniels bottle.
Squeeze the cap with you fingers to satisfy that it is a #7 cap. Mine is on the jug that came off a newer car.
No pressure cap ! O.K. , you can run a 4# cap if you insist but adding a puke tank works much better . Welcome to 1940's technology , if you fight it , you'll soon go crazy . learn to live with it (and check the coolant often) and you'll be like me ~ zooming across Death Valley overloaded in the 125* heat @ 75 MPH and not worrying . I run a 187* thermostat with a tiny " steam hole " drilled in the flange . You can try a 160* but you MUST have a thermostat ! . Just for giggles , how many rows of tubes are in this radiator Ken ? (looking in the filler neck .)
Thanks for the input guys. Nate, it has 3 rows of tubes. Hopefully will go to NAPA today and get a zreo pressure radiator cap, once I get SWMBO's honey-do list knocked out. How far below the filler neck should I fill the radiator? Thanks again' Ken
O.K. good . I assume the V-Belt is tight enough to when you force the fan to turn by hand , it squeaks ? . What is the mix of coolant and water used ? I generally use 60 % water (distilled of course) and 40 % coolant . You can also use " Water Wetter " , it's cheap @ Pep Boys and worked well in my son's racecar . I fill to maybe 1" above the tubes when hot , it's WAY below the filler neck as any excess gets puked out quickly . I assume the coolant looks clean and fairly clear ? not cloudy with sediment that stirred up after the repairs ? . I hope this helps .
Here is what I remember from a long time ago. First water expands and has to go somewhere, hince the overflow tank. It will fill and empty as the collant expands and contracts. An overflow tank is the best way to keeping you vehicles coolant at the proper level. Second, for every pound you increase you cap it raises the boiling point about 2 and 1/2 degrees. So if you are running a 7# cap you effective raised the boiling point from 212 degress to almost 230 degrees. With this being said it still expands and has to go somewhere, that the over flow tanks job. Last, living in Arizona, I run 185-190 termostates. Reason for this is as you run down the road with a 160 degree temostate it will always stay open. The radiator does not have time to cool the water in the tank (radiator) before dumping it back into the engine, thereby causing the vehicle to over heat while running down the road. At idle and short trips usually will not overheat until on freeway. Hope that is helpful. Rick
Pressure & Cooling Right , 3 degrees higher boiling point of plain water for each pound of pressure . The deal is : these rigs are not really designed to run any pressure so I hold the line at 4 # MAX . Correct valve gaps and ignition timing have everything to do with cooling too.
Nate, this is why you're the master... and I will always be the grasshopper. I actually thought about the v-belt and grabbed the fan and turned it. It offered a little resistance, but did not squeal. When I get done tightening it, it will! Unfortunately, my day full of honey-do's kept me from getting to Napa before they closed and the FLOPS, not FLAPS didn't have a clue what a zero pressure radiator cap was! I'll keep you guys updated! Thanks for the help! Ken
Radiator Caps If you go to your FLAPS and look in the book , I bet it'll have the Stant cap P/N right there , asking the current crop of " parts Counter Guys " for anything , even the spark plugs for a '97 Toyletta , is pretty much a waste of time I'd go look in MY old Stat catalong but the (well meaning) retard on Swing Shift , cleaned up and tossed out most of my books long ago I'll go look 'round the shop and see if I can find a catalong hidden away . Remember : when tightening the fan belt , DON'T use a long prybar or crowbar ! loosen the adjuster and the mounting bolts at each and them hold the gennie away with one hand whilst your other hand snugs up the adjuster bolt , then re-tighten the lower mounting bolts . Too much tension will ruin the bearings in the water pump , the gennie or both
CORRECT Radiator Cap O.K. , Stant catalong says 1937 ~ 1952 ALL GMC & CHEVROLET trucks is : 10203 . old P/N is : R3 . This is for a non pressure cap , it still seals so the resivoir tank you mount will draw coolant back in via the overflow tube ~ I don't cut the tube off short , rather I mount the tank up as high as I can on the firewall so it'll siphone back into the cooling system as necessary . Last thing I knew , Pep Boys was an authorized Stant dealer so they can order one , should be cheap . I hope this helps .
Nate, thanks for the p/n! I've been to most of my local FLAPS to no avail so far. Armed with this info, I'm sure I'll score one soon!
I'm always learning more and more about less and less! Ken, I have a 4lb Stant cap on my 47' with Stock 216 with a stock Radiator, the fluid level is above the coils and below the cap a couple inches. It holds the fluild well and runs cool here in Tennessee. If I fill it higher it spits some out. I use a thermostat from our host but I think it is only 165 degree. Now my 53' project under way is different. It is a Southern California truck, it has a 235 and someone has cut the old radiator housing and added a newer larger radiator. The truck runs cold here in Tennessee. My temp gauge only goes up to 150 degrees after a good run. I checked and there is no thermostat in it. There is a 16 lb Stant cap on it. After reading the posts, I think will put in a 185 degree thermostat and a lower pressure cap. Does that make sense to everyone? How much pressure should a new cap hold? I'm thinking a 4 lb cap will let it go to 220 degrees give or take. Thanks Flashlight
I scored a zero pressure radiator cap last Saturday, did some tweaking and gave it a nice long drive on Sunday. No sign of overheating, very small amount of anti-freeze on driveway. Looks like I'm getting there. I thought I remembered seeing an original puke tank at mom's the last time I was home. Called her on Monday and asked her to go to the utility room and check to see if there was a green tube looking thingy trying to explain it to her in words she'd understand, right? She came back with something that astonished me. "you talking about that radiator overflow tank that your father picked up at the Louisville swap back in '87?" "yeah". "it's still there" she said. Looks like I'll probably end up putting that on soon. Thanks for the input (as usual) guys. BTW, I found the radiator cap at O'Reillys. If anyone needs a zero pressure cap and lives near an O'Reillys, the brand they sell is Murray and the part number is 7003. It cross-referenced to the Stant 10203. Ken
Yes. The 1951 Accessories Manual shows how to mount and plumb it. Here's a link to it. http://chevy.oldcarmanualproject.com/accessories/1951am/51aim07.htm
