The radiator in my ford 1953 f100 is a stock truck radiator. The motor is a 302 ford vintage 1987, The truck was running hot so I just had The radiator acid cleaned and rodded,I'm running a 75% mix of anti freeze and distilled water. The pressure cap is the old stock one I think? I should change it put not shire about the pressure setting to get. I drove the truck out over the weekend and in the cool morning the truck ran about 180% and in the hot afternoon it ran 195%+ The thermostat is out of the motor and I'm running a electric fan with a by pass switch. I also don't have a fan shroud. The radiator sits a little high compared too the engine Thinking of making a shroud deflector to shoot more air down to the motor. Trying to make the truck run cooler when stuck in traffic thats when the temp rises. One of my friends told me to change the cap it may help? I also don't have a expansion tank so if I loose some fluid it,s on the ground. Thanks Joe
lower PSI cap will bring the boiling point down,older cars/truck used lower #'s where newer cars have higher #'s which have higher boiling point,a shroud could really help with cooling,& 195 doesn't seem too high! just my 2¢
The radiator shop should have told you what pressure cap to run. This depends on the condition of your radiator. You could go back and ask them or be conservative and toss a 9 lb cap on it and see what it does. A 12-14 lb cap would be really nice. But 195* isn't really that hot, a shroud should be a big help. Bob
Put a stat in it first and if that does'nt do it build a shroud. I forgot the question was about psi cap. Find a motors manual for that year and it should have the spec. I'd still do the first stuff though.
The pressure setting of the cap has nothing to do with the operating temp of the engine. Let me repeat that. The pressure setting of the cap has nothing to do with the operating temp of the engine. The only thing the pressure rating does is control the temp at which the coolant in the engine turns to steam. That's it. It's a physics thing. The higher the pressure, the higher the temp of vaporization. It will not make it run cooler. It can keep it from boiling over at the higher temp but it's still that hot.
might be that without the stat and siitting in traffic with min flow of air to cool the radiator ,and no shroud its bound to warm up.try a shroud,180 stat and a 9 lb cap,and a puke can.
I found a expansion tank that I can use so I"ll install That tonight and will look for the shroud that I had at one time maybe cut it down so I get more air flow toward the engine. The thermostat ?? I may run out of time to test it. I got a cruise pass for Lake George nationals this weekend the show starts Friday and they let you cruise closed off street at night . This will be the first time for this The truck has given me a lot of grief to get it to run! Just worried about being stopped in traffic for long times at the show. Thanks Joe
Probably wouldn't hurt a thing to throw a thermostat in it as well. And as everyone has said that late model engine @ 195 is just getting warmed up.
Antifreeze beyond a 50/50 mix does not necessarily cool better. Usually, it's just the opposite. Pure water cools best. I'd look at a 50/50 mix instead of the 75/25 you have now. Also, 195 is not HOT.
Are you running an electric fan and the engine fan? The thermostat is important to slow down the water and give it a chance to cool. 195 is not hot but if you get in traffic it could be a problem.
Yes I'm running a electric fan, I have to agree with everyone on the thermostat. On my lunch I ran to Napa Got a 180% thermostat and ordered a 4lbs cap that is the right pressure for the older radiator . Got a quart and half expansion tank off a older Gmc. that fits good to the inner fender . Will install all this stuff tonight and start looking for a shroud or build some type of deflector to shoot the air flow down on top of the motor.
That is a good start sir, but does your fan push or pull, as in is it in the front or back of your radiator?
The fan is mounted on the back( engine compartment area) pulling the air threw the radiator will have to check on rotation?? can you reverse the wires? Maybe get more flow of air??
An old stock radiator with a big top tank should not have a high pressure cap on it, the radiator will bulge and be destroyed. Run the stock type cap. Or get a modern radiator if you want to run more pressure. 50-50 antifreeze and a 4 or 7 psi cap keeps the big blocks in my old chevy trucks with stock radiators, from boiling over....
If it the wrong rotation it will be trying to push air back through the radiator. The easiest check is to put a piece of paper on the front of the radiator with the fan running, if it sticks to the radiator, it is turning the right way, if it blows off - wrong way. But the fan blades are designed for pushing or pulling, just reversing the wires will not make the wrong fan work right. Some fans the blades can be taken off and turned around, some can't. The catch tank or Expansion tank will not make it run any cooler, it just catches the water that pukes out when the thing gets hot, especially after you shut it off. With the correct type of cap, it will then suck the water back in when it cools off. This will not happen with an original style cap. You also do NOT want to put a high pressure cap on an original F100 style radiator. That giant top tank cannot take the pressure and it will blow itself apart if the pressure gets too high. And as others have said, a higher pressure cap won't lower the running temperature anyway. And get rid of the 75% coolant, this will hinder cooling, not help. Also 195° is nothing to worry about. Don't start to freak out until you see 220-230°
I got a 4lbs cap ordered from napa, you stated getting the right cap at a lower pressure? Were you refering to the old stock caps or aftermarket replacement What Kind of cap should I get Thanks Joe
Use any brand of 4 lb cap that fits(if that is what they used in 1953). The idea is to not overpressure the rad. Put in a 180 thermostat. It should be fine. Don't expect it to run at 180 that is where the thermostat opens in other words the minimum not the maximum. As long as it stays below 200 you will be fine. On a hot day in traffic it could go up to 210 with no harm done.
I got old stock radiator, that was just cleaned, getting a new 4lbs cap from Napa tomorrow, I guess you would call it a dump line on top of the radiator. I don't want to increase pressure was wondering if I set up a recovery system for fluid would it work?? or am I wasting my time on that. Thanks Joe Just trying to cover all angles.
A stock style cap will not work with a recovery tank. It will allow the water to spew out into the tank when it is overfilled or it over heats, but it will not open up to suck water back in when it cools. You should be able to find a 7-9 lb cap that works with a coolant recovery and that pressure should be fine with the stock radiator.
I just had some pinhole leaks and a crack fixed on my rad for a 1950 Chev with a 216. When I picked it up the owner (really old guy, has run the place for 40 years) said I had a 15psi cap on it and it was FAR too much pressure for a rad of that age. He gave me 7psi cap and said that should be much better.
Just leave the coolant level an inch or two below the top of the radiator, and it won't overflow, and everything should be fine. That's how radiators all worked up until the early 70s when they started getting overflow recovery tanks. It's not rocket science.
I run as high pressure cap as I can without radiator distortion and 50/50, as said 195 isn't hot (if it is steady)
I would still be looking for some form of blockage in the engine or somewhere. My reasoning is that if you are running at 195o without a thermostat it suggests that there is some form of reduced cooling somewhere in that engine. On something of this age the engine should run cooler than 180o without the thermostat and if it is running at 195o without it I would be looking to flush the block and/or check how much gunk is sitting behind ther freeze plugs. This era of engine were not built to run high temperatures like todays modern engine and the capacity in the radiator was in excess of what it needed. Modern day engine run smaller radiators with higher poundage radiator caps with different recovery style operqations and higher temperatures so they can make a little go a longer way.
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