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with the world of cheap parts, ( i put in a Chinese heater core) and Old radiators (mine is 35 y.o.)
And I think I just blew a water pump that was not that old
looking for a balanced way to manage heat and breakdowns.
they call this a dilemma right?
A higher or lower pressure cap does not manage over heating per se', it manages the boil over temperature of you coolant.
A lower pressure cap will allow the coolant to boil sooner than a higher pressure cap.
Of course it you boil over then coolant is lost and THAT will cause an overheating problem as there is insufficient coolant to cool the engine properly.
Take a look at these two charts. One shows the relationship of antifreeze to boiling temp and the other pressure and boiling temp.
So a pure water coolant will boil at about 250* F under 13 psi. adding 50% antifreeze will add approx another 13* to 14*. Using both will give boil over protection to approx 264* or so. Boiling over is not the only concern. Local temperatures near the heads will be considerably higher than the temp gauge is reading and bubbles may form in that region if those temps exceed your boil over temp protection creating local hot spots.
A higher or lower pressure cap does not manage over heating per se', it manages the boil over temperature of you coolant.
A lower pressure cap will allow the coolant to boil sooner than a higher pressure cap.
Of course it you boil over then coolant is lost and THAT will cause an overheating problem as there is insufficient coolant to cool the engine properly.
Take a look at these two charts. One shows the relationship of antifreeze to boiling temp and the other pressure and boiling temp.
So a pure water coolant will boil at about 250* F under 13 psi. adding 50% antifreeze will add approx another 13* to 14*. Using both will give boil over protection to approx 264* or so. Boiling over is not the only concern. Local temperatures near the heads will be considerably higher than the temp gauge is reading and bubbles may form in that region if those temps exceed your boil over temp protection creating local hot spots.
as i have discovered my "old" cap had a very weak spring, and i was puking into the overflow tank and then out the tank, unknowingly, while driving.
i squeezed the rad hoses and coolant would go back and forth past the cap
i pop the hood often and saw the mess,
i suppose with virtually no pressure, what was showing on the f/u unreadable stock gauge is lower not indicating boiling, but a actuality it was,; right into the overtank.
so you are saying the temp gauge is always reading lower than actual
really want to try a 13 on there
and yes my W/P sprung a leak, took it out today.....it's dead
Hope the water pump thing was just a fluke
Once the new ones on may want to pull the plugs and do a pressure check on the cooling system to make sure theres nothing more going on. Some auto parts stores will loan or rent the piece to do that can do it right in their parking lot if need be
When I lost a head gasket on a former 89 it was impossible to spot, eventually blew the WP seal and the hose off the radiator. Sometimes run normal around town, longer trips on the fwy it would heat up some.
Finally blew its cookies on the smog machines rollers...and passed lol.
1 thing at a time dont use a lower than stock cap btdt
so you are saying the temp gauge is always reading lower than actual
No. The temp gauge is showing you the temperature of the water passing it. It is representative of the average temperature of the water in the engine in the area it is located.
What I'm saying is that there are areas hotter and colder than what the temp gauge shows. Hotter ones are in the hottest areas, ie near the exhaust port in the heads.
i suppose with virtually no pressure, what was showing on the f/u unreadable stock gauge is lower not indicating boiling, but a actuality it was,; right into the overtank.
Your gauge may be completely accurate. The water starts expanding long before it reaches boiling temperatures.
As it expands the pressure builds in the cooling system with a functioning radiator cap. This is normal.
If your radiator cap could hold no pressure then the expansion of the water would push it into the overflow tank instead of building pressure and remaining in the cooling system (engine /radiator) as it should.
Hope the water pump thing was just a fluke
Once the new ones on may want to pull the plugs and do a pressure check on the cooling system to make sure theres nothing more going on. Some auto parts stores will loan or rent the piece to do that can do it right in their parking lot if need be
When I lost a head gasket on a former 89 it was impossible to spot, eventually blew the WP seal and the hose off the radiator. Sometimes run normal around town, longer trips on the fwy it would heat up some.
Finally blew its cookies on the smog machines rollers...and passed lol.
1 thing at a time dont use a lower than stock cap btdt
like i said , i put that weak azz cap back on today and pinched the hose a few reps and sure enough it was letting coolant thru "again" like it did everytime i check prior to the new 16 cap
put the 16 cap on and like reelav8r says the water expanded even right after start-up, and the hoses plumped and got a hard-on... then the pissing started at the water-pump
i hope not, the car did overheat once, when i was test fitting the stock e-fan sans mech fan, no bottom spoiler, couldn't cool worth a crap even at 50mph,
since been remedied
could have blown the head gasket, but that was last summer... but who knows
no water in the oil, but i could smell something burning in the overflow tank area with the heater fan on
hope it's not blow-by coming out the tank and into my HVAC intake vent aft of the hood.... makes me nervous
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.
"pull off the 2 heater hoses and hook them to a "U" tube" My 68 convert came this way, but not for cool cruising (in TX) where the car came from. The PO was too lazy to replace the leaking heater core, so he just disconnected it. I replaced it for those chilly nights here in the "north" in VA. RA
"pull off the 2 heater hoses and hook them to a "U" tube" My 68 convert came this way, but not for cool cruising (in TX) where the car came from. The PO was too lazy to replace the leaking heater core, so he just disconnected it. I replaced it for those chilly nights here in the "north" in VA. RA
I hope you hung onto the "U" tube 'cause if you got a Chinese replacement heater core you may need it someday.
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?
that's part of the problem. the system is not efficient, and heat is not under direct control nor consistant. there are hot spots in various areas, and others that are less efficient at flow, not all passages the same, elbows, turns, etc. although you may hypothetically average 180 or 190 in a properly working system, you will see a larger variance of temp throughout the motor. couple that with the need for excess capacity due to variations in state of tune, hot weather, wearing of components, loss of coolant, driving style, etc. and you'll see why you need that pressure. if we could guarantee a fixed rpm and fixed conditions, you could get away with a system like an old hit-and-miss engine...
that's part of the problem. the system is not efficient, and heat is not under direct control nor consistant. there are hot spots in various areas, and others that are less efficient at flow, not all passages the same, elbows, turns, etc. although you may hypothetically average 180 or 190 in a properly working system, you will see a larger variance of temp throughout the motor. couple that with the need for excess capacity due to variations in state of tune, hot weather, wearing of components, loss of coolant, driving style, etc. and you'll see why you need that pressure. if we could guarantee a fixed rpm and fixed conditions, you could get away with a system like an old hit-and-miss engine...
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.
I've had a lot of leaky heater cores over the years, and they seem to fail because they have corroded through. I think once the brass is corroding through all the stop leak in the world won't fix it for any length of time, in my experience.
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/
This is the correct answer, but it is not more expensive because you never have to buy coolant again. Presumably you will keep your Corvette or pass it along to someone else who will appreciate the maintenance free benefit.
I've had a lot of leaky heater cores over the years, and they seem to fail because they have corroded through. I think once the brass is corroding through all the stop leak in the world won't fix it for any length of time, in my experience.
i guess regular coolant flushes will help with the heater core corrosion, that is what i am trying to do, less corrosion,less chance of blow out
routine, preventive, corrective and deferred...maintenance.
Every pound of pressure raises the boiling point 3 1/4 degrees. You do not want your engine block to boil. I would not go lower than 15 PSI pressure cap at the radiator.
i guess regular coolant flushes will help with the heater core corrosion, that is what i am trying to do, less corrosion,less chance of blow out
routine, preventive, corrective and deferred...maintenance.
Regular coolant flushes will help as new coolant has the correct corrosion inhibitors, but there is still some corrosion. If you plan on keeping your car for a long time, it's just easier, cheaper and better to covert to Evans IMHO.
01-31-2016, 09:50 AM
