New paint on my 68

looks great............................

RodStRace wrote:Looks good!
Cooling is a matter of having a radiator big enough and in good shape, a water pump that circulates the coolant, and enough air flow to drop the temp in the radiator.
You also need the engine tuned so it doesn't run hot, no leaks and a thermostat that opens fully. At 190, the radiator cap doesn't matter, but if it runs at much more than 200, the pressure cap comes into play.

The pressure cap will effect it as water boils at a higher temperature when under pressure so with a good cap (18psi ish) it will run at a higher temp without boiling , anti freeze and stuff like water wetter etc can help too , if it's holding pressure and not losing water and you've had the rad checked and the impellor hasn't fallen off the water pump and the thermostat is good, check the timing and carb tune ,
Good luck
Wayne

Nice paint job by the way !

At 190 the cap doesn't matter. What I mean by that is if the cap is keeping fluid from spilling out but does not hold pressure, the system will not depend on the pressure.

At higher temps (water boils at 212) pressurizing the system will keep the water from boiling.
Also, if it's 190 at the top of the motor, it will have hot spots around the exhaust ports and combustion chambers that are higher. That's why I didn't say "At 210". At that temp, there would be localized boiling that would be controlled by pressure.

I have seen many cars that run at 190 consistantly that do need a pressure cap. It's when the engine is shut off and there is no flow. That's when they will 'puke' due to boiling. This is different than running hot, though.

If all this fails to sort it out it might be worth taking some of the freeze plugs out of the side of the block , i've had engines where there was crap in the bottom of the block and it was half way up the freeze plugs ! , lots of things to check !

Thanks for the info. The engine was just rebuilt and it was cleaned good, water flowed through it as it should. The radiator was flushed and cleaned and I put in a new water pump. What has seamed to help is emptying most of the fluid and going with water and water wetter and a half can of anti corrosion lube. Brought it down about 15 to 20 degrees. It was hot yesterday and I drove it to work, got to 210 but not above, even while sitting. Dropped a bit while moving and the upper hose wasn't to stiff from pressure. The only other thing I may do is go with a high flow fan. I was thinking either a high flow mechanical or a electric thermostat controlled fan that will run high even at idle, just don't know about the noise from a electric.

One other thing I was going to look at is sealing between the radiator and belly pan but that would not help while sitting.

Did you say you had a fan shroud on it? if not I would definitely put one on...it will make the fan pull air through the rad. There are a lot of nice tunnel ideas also, if you fill like modifying the floor. Overheating in these old vans is primarily caused by so much of the rad being up high in the dog house and the pan underneath having to many air gaps in it, and no fan shrouds. By far this design of these vehicles-- be it ford, dodge, or Chevy, have all had heating problems at one time or another. Now I could be wrong and someone correct me if I am. According to my Dad, when he had the Ford van...it boiled over in traffic, if the van didn't stay moving. But it never had a fan shroud either??? I have a 3 row radiator getting made as we speak and I will make a shroud for it and see how i goes before I cut the dog house and make a tunnel. Also running a 350 small block with 165 degree thermostat.

I have a 6 blade fan on mine and from talking to my dad he never had it overheat on him, except when the thermostat stuck when I was riding in it once. He daily drove for about 15 years too. The fan is the only on the cooling system not stock, the radiator was recored as well though.