Radiator Cap Mod (Cooling System Pressure)

[F16pilotjd]

Thanks. Have my work cut out for me. Will keep you posted.

 

[imp]

I'm holding my tongue after reading this thread. Re-engineering via knife-blade on radiator pressure cap seal is, well, .....I said I'd hold my tongue........imp

 

[1998Exp]

Do not follow the advise offered in this thread. I replied to your other identical post (in another thread) on this subject. Every pound of pressure in the cooling system, added by the pressure cap/radiator cap, reduces the boiling point of your coolant about 2-3 degrees F. It is a good thing, as long as your are using the cap specified for your radiator (usually 16 PSI). I explained the probable source of your pressure problem in the other thread.

Koda, hopefully what you wrote here is a typo, as increasing pressure RAISES the boiling point of the coolant. Actually, contrary to the effect on freezing, the effect of adding ethylene glycol to water on increasing the boiling point is fairly small - about +15F at 50% concentration. The effect of pressure is, however, much larger. At 15 psi pure water boils at 257F, and coolant with 50% ethylene glycol boils at 267F. Obviously, raising the boiling point is a good thing, because steam (a gas) won't do much to cool the engine.

 

[koda2000]

Koda, hopefully what you wrote here is a typo, as increasing pressure RAISES the boiling point of the coolant. Actually, contrary to the effect on freezing, the effect of adding ethylene glycol to water on increasing the boiling point is fairly small - about +15F at 50% concentration. The effect of pressure is, however, much larger. At 15 psi pure water boils at 257F, and coolant with 50% ethylene glycol boils at 267F. Obviously, raising the boiling point is a good thing, because steam (a gas) won't do much to cool the engine.

Yes - I meant to say RAISES/increases the boiling point. I'll edit my post thanks. And did you know that plain water is actually a better coolant than water with ethylene glycol?

 

[trustsindelar]

Yesterday morning I've noticed some yellow-ish fluid that seemed to drip from under the truck onto the white snow beneath, and my first guess was that it was either prestone or possibly fuel (I filled up to the very top just minutes before). After inspecting the truck for more leaks later in the day, I came to to the conclusion that I was not leaking anything, at least visibly.

I nevertheless spoke with a professional mechanic (with many years of experience), just to find out what it might have been. He had told me that many smaller prestone leaks can be eliminated by removing pressure from the cooling system, and that can be achieved by cutting small notches in the lower gasket of the radiator cap (the smaller round gasket) or cutting the cap spring - this supposedly brings pressure to 0, and since the system is not pressurized, hoses do not swell up and don't leak. He stated that he runs all his vehicles (new and old) like that for many years, and has never had a problem. The only apparent side effect is the fact that the heater takes a bit longer to blow warm air.

I just did that mod to my Ex, and will monitor it closely... If anyone has any suggestions or remarks about this, please feel free to voice your opinion. I don't think my Ex has any leaks, but the idea of running a no-pressure cooling system to preserve the hoses and gaskets seems to make sense to me, even at the expense of waiting a bit longer for heat to kick in during winter.
[/QUOT The only reason cooling systems (in gasoline engines anyhow, diesels are another story for various reasons) are pressurized is to raise the boiling temperature of the coolant. A slightly 'stronger' mixture of glycol/water, i.e. more glycol, will do the same thing to some extent and negate the need to pressurize the system. I have been removing the lower seal on radiator caps on vehicles from the 70's to present vehicles and have suffered no ill effects; time for engine to warm up and heater to work is not changed noticeably.