Water Pressure Issue
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Water Pressure Issue
Current situation.....When I drive my car for any amount of distance it builds water pressure. After a drive the radiator top hose is pretty hard to squeeze. After the car cools down it retains pressure in the cooling system. I pull the pressure relief tab on the cap to relieve the pressure. It spits out enough water that I have to add some back before riding again. If I just let it set and not let the pressure off water eventually seeps out the front and back externally where the water jackets in the heads and intake join. I noticed this past week after I drove it on Saturday I let all the pressure out after it cooled down and put the pressure relief tab back down. When I went and cracked it again on Thursday after just setting all week it had built up pressure in it again....not a lot but some. I put gasket sealer around both sides of the gasket around the water ports when I put it together. While running, water doesn't seep out. There has been no indication at all of water in the oil either. I did the test of combustion gases in the cooling system and it tested that it was combustion in the cooling system. I can't figure out for the life of me where it could be coming from because the motor runs great with no issues. Does not loose water except for what it pukes out when the relief tab is pulled on the cap
The motor is a small block Chevrolet
Dart Iron eagle Block decked
Cometic head gaskets # CGT-C5249-070 MLS (It has 12.5 compression)
ARP Head Studs #234-4336
Dart 9* Ultra Pro heads new when put on the motor
Meziere electric water pump 42 gph
Radiator is a Be Cool factor replacement with a 16 lb cap
Any ideas would be appreciated.
The motor is a small block Chevrolet
Dart Iron eagle Block decked
Cometic head gaskets # CGT-C5249-070 MLS (It has 12.5 compression)
ARP Head Studs #234-4336
Dart 9* Ultra Pro heads new when put on the motor
Meziere electric water pump 42 gph
Radiator is a Be Cool factor replacement with a 16 lb cap
Any ideas would be appreciated.
Re: Water Pressure Issue
Combustion gas in coolant test shows you have a combustion leak. Since it is building pressure I vote for a leaky head gasket. Next would be a cracked cylinder. Could be a cracked head. About all there is.
Re: Water Pressure Issue
Seems like combustion pressure in cooling system.
Is it a wet recovery system or are you running expansion space in the radiator ?
Cap pressure and recovery valve operating and to spec' ?
Is it a wet recovery system or are you running expansion space in the radiator ?
Cap pressure and recovery valve operating and to spec' ?
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Re: Water Pressure Issue
It tested positive for combustion gas in coolant so ,of course, it is combustion pressure pressurizing his coolant and not anything to do with his cooling system. Therefore the cap and type of cooling system has nothing to do with his issue.
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Re: Water Pressure Issue
In addition to measuring and logging coolant temperature, we often track coolant pressure.
Frequently, the coolant pressure exceeds cap limits. Much depends on where the pressure is measured.
Often the cause is local flow blockage, especially when multiple radiators are being used.
Gas in the cooling system can originate from local coolant boiling. At some point the gas
pressure can lift the head and allow the addidtion of combustion gases.
Frequently, the coolant pressure exceeds cap limits. Much depends on where the pressure is measured.
Often the cause is local flow blockage, especially when multiple radiators are being used.
Gas in the cooling system can originate from local coolant boiling. At some point the gas
pressure can lift the head and allow the addidtion of combustion gases.
Re: Water Pressure Issue
Care to expand on the last paragraph? I'm having a hard time seeing that happen.
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Re: Water Pressure Issue
Gas in the cooling system is steam resulting from coolant boiling.
Even though the system is pressurized, which raises the coolant boiling point, at some temperature
it will boil, expanding the volume massively.
I should have made the distiction between combustion gas and steam gas.
Re: Water Pressure Issue
Thank you ,I understand that and did not think otherwise. What I cannot see is gas/steam/whatever in the cooling system building enough pressure to raise a head causing a combustion gas leak to the coolant. If the cooling system had no rubber hoses and was able to totally contain the steam pressure from a localized steam pocket I ,of course,see what you describe being able to happen . I mean something has to give but I just am very skeptical of an automotive cooling system being robust enough to contain the pressure causing a head to lift. Too many other places that will yield first namely hoses/radiator/heater core. I am not meaning to be argumentative since you are much more knowledgeable than me. I only seek to understand.
Re: Water Pressure Issue
Perhaps I'm just being impatient,my apologies if so, but I would truly appreciate an explanation.
Re: Water Pressure Issue
Yer misread that bit.
Fortunately for me my last couple of suspected head gaskets have been cap issues.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Re: Water Pressure Issue
The op plainly stated he tested for combustion gas in the coolant and it tested positive. I didn't miss a thing unless you can point it out for me.
Re: Water Pressure Issue
I missread that bit.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Re: Water Pressure Issue
As I said earlier I apologize if I'm being impatient but I'm really interested in the above. If David Redszus could possibly help me understand .fabr wrote: ↑Sat Jun 18, 2022 3:29 pm Thank you ,I understand that and did not think otherwise. What I cannot see is gas/steam/whatever in the cooling system building enough pressure to raise a head causing a combustion gas leak to the coolant. If the cooling system had no rubber hoses and was able to totally contain the steam pressure from a localized steam pocket I ,of course,see what you describe being able to happen . I mean something has to give but I just am very skeptical of an automotive cooling system being robust enough to contain the pressure causing a head to lift. Too many other places that will yield first namely hoses/radiator/heater core. I am not meaning to be argumentative since you are much more knowledgeable than me. I only seek to understand.
Re: Water Pressure Issue
Pull plugs, inspect for possible color variation, keep in order, grab compression tester., pull out Schrader, and rig it up to apply shop air into each cylinder at tdc. Leave radiator cap off, watch for bubbles and/ or coolant level to raise, wait a bit, 2-5 minutes, maybe longer, try it with engine cold or warm, that 120 -150 psi will usually show up a sealing failure. A crack down in bore ? We blank off rad and hose conns. Use air connection screwed into plate at thermostat opening and inspect each cylinder with boroscope at bdc, with water in block.
Re: Water Pressure Issue
Another point, I used to use a 4 gas meter to check for CO at radiator cap opening and NAPA blue fluid rig on radiator to check for combustion gas, not sure what you are doing, It takes time, but the shop air test has yet to fail , and the napa Blue fluid has a shelf life of 2 years. Let us know what you find out.