slickfx3

i was reading higher radiator caps ~16lbs can blow radiators, hoses and heater cores

i do not want to redo the heater core ever

is this a good place to look to relive some pressure?

resdoggie

Where did you here that? Not true anyway. If any of those components fail, it's not due to pressure but due to defective, worn or corroded parts.

toobroketoretire

It would make sense to lower the "blow off" pressure to protect the heater core but they almost always fail because of a soldered tube leaking because of a poor solder job. If you're worried about the core leaking just use a container of Barz Leak in your system because it won't hurt anything and will seal any little leak when it starts. I have read ordinary black pepper makes an excellent stop leak and its certainly very cheap.

slickfx3

yes i heard GM recommended tablets for some Buicks prone to leaks , i am no against putting stuff like Barr powdery stuff in car,

i just changed the heater core and i think my cap is blowing off early, since i puke all the time, even with very low temps

i am going to grab a new one today, and was wondering if i can go lower than the 15 called for in the repair manuals

flyeri

15 or 16 lbs should not be too high. Do you have a recovery tank or does yours puke on the ground? If on the ground, are you filling the radiator full or leaving room for expansion? My Griffith radiator (pukes on ground) will settle at a level maybe 3 inches or so below the bottom of the filler. It bothered me until I counted the exposed cores and discovered that it was always at that level when cold. If I added more it would be back to the same spot after a drive and cooling again, and yes, there was evidence of coolant on the bottom of the drain hose.

Try letting it puke out and cool all the way down. Check the level the next day. Drive again and see where it ends up after cooling from the second drive. Unless it is puking half of the radiator I would guess it is seeking it's happy level. If it's losing more than a couple inches from full you have another problem.

slickfx3

1982 i have an overflow tank, just bought a new 16lb, i think the spring on my old cap was weak and letting go too soon

7T1vette

Lower pressure provides less "stress" to the cooling system...at the expense of coolant boiling at a lower temperature.

If your system stays reasonably cool, it shouldn't have a problem operating with a lower pressure cap. Just maintain about a 50/50 mix of coolant and distilled water to keep coolant boiling point as high as possible.

ezobens

If you're worried about pressure, why not run waterless coolant?
It's expensive but the benefits outweigh the initial investment IMO.
http://www.evanscooling.com/

slickfx3

i am at 60/40 could not get more in, and i read less coolant= higher boiling point correct?

it is not self fulfilling? if the system is efficient, and heat is under control let's say hypothetically ~180*

then even though a higher number cap is installed, the actual pressures are not even close to the number on the cap correct?

and in this case the higher number cap is just an insurance policy against after-boil and boiling right?

7T1vette

The cap calibration is for when the coolant begins to boil over. Once it boils, the pressure increases greatly. The cap relieves the pressure and protects the system. But, a system with a 7 psi cap will relieve sooner than one with a higher pressure; thus, it will protect the system from higher stresses...and possibly rupturing the heater core.

With ethylene glycol coolant, about a 55/45 mix is optimum for max temp capability. But 50/50 is usually recommended mix, as it is easy to do. With a lower ratio...or higher ratio...of water to coolant, the boiling point reduces. Check the boiling point table for exact ratio differences (Google).

doorgunner

My project car would puke a spot about 1 sq. ft./not much, after a week of driving the radiator was low enough to get the 180* temp up to 220*.

I added a coolant recovery tank in an "undisclosed location".......haven't needed to add coolant since!

74modified

Because of expansion due to heat, the pressure can rise without any boiling. A lower pressure cap will vent and maintain the lower pressure = less likely to damage any weak points. If your system is maintaining a lower temp so you don't need the extra pressure you are good. But watch out for a higher temp after shutdown as the coolant flow stops, but heat is still being absorbed in the engine. This could cause blow off when you shut down. Another thing to think about, along the same line, is maintaining/changing the coolant so you keep a less corrosive fluid in there.

REELAV8R

Your cooling system for the 82 is always kept full. No air in the system/radiator.

So your cap will always let coolant into the overflow tank as it heats and expands.
Water/coolant is incompressible. So as it heats it is forced past the cap into the overflow tank due to expansion.
Then as the system cools after you shut it off the fluid in the overflow tank is drawn back into the radiator to maintain it full.
This is why there is a "full cold" and "full hot" line on your overflow tank.

Now if your overflow tank is overflowing that is due to overfilling the tank or a blown head gasket.

slickfx3

i hope it's not a blown head gasket, if that were the case would coolant get sucked in to the C- chamber and out the tailpipe as well???

i would squeeze the hose and the coolant would go past the cap and into the overflow,

i put in a new 16 cap yesterday and now my water pump in leaking

are aluminum water pump available for the c3?

resdoggie

Yes, aluminium wp's are readily available. But not all small block pumps are the same. There are long, short and corvette styles.

Easy Mike

So go back to the stock 15lb cap. A helluva lot cheaper than an aluminum water you probably don't need.

Just the same, it's your money and your car.

slickfx3

they didn't have the 15lb is 16 too high?

REELAV8R

bad cap then

Leaking from where?

Around the shaft, you'll need a new pump. where it bolts to the block or around a hose connection and you just need to fix that with a gasket or hose clamp or new hose.

mickey5

For all the guys up north that cruise all summer and store all winter; who needs a heater? Just pull off the 2 heater hoses and hook them to a "U" tube. You'll never have to worry about the heater core leaking and get a cooler summer ride.

slickfx3

i had to put the car away

i'll need to take another look