Jon fails at reading...
You said before your hoses were new. Keep them. Its a hose... not technologically advanced at all. If there is something wrong with it, you will know it.
what would cause extreme coolant pressure in the block
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PapaSmurf2k3
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srpowered240sx
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Re: what would cause extreme coolant pressure in the block (PapaSmurf2k3)
if a hose starts to bubble, inflate, and expand, there is usually a problem.PapaSmurf2k3 wrote:Jon fails at reading...
You said before your hoses were new. Keep them. Its a hose... not technologically advanced at all. If there is something wrong with it, you will know it.
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tramp_drift240
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Re: what would cause extreme coolant pressure in the block (srpowered240sx)
its not bubbling or expanding. theres just pressure in it.
whatevers causing the freeze plugs to keep leaking is the same thing thats causing my hoses to get like that. when the cars running at normal temperature, when i squeeze the hoses, its like theyre filled with air.
whatevers causing the freeze plugs to keep leaking is the same thing thats causing my hoses to get like that. when the cars running at normal temperature, when i squeeze the hoses, its like theyre filled with air.
Re: what would cause extreme coolant pressure in the block (tramp_drift240)
Look, wouldn't you think that the Thermalstat have to do something with regulating the flow?tramp_drift240 wrote:im still iffy on the thermostat. why would i need new hoses?
im going to get the compression tester today. ill see what numbers im getting in each cylinder, then continue from there. i dont want to replace little things just to have my freeze plugs leak again. im getting tired of replacing them.
I don't know and it may seem contradictory, but the thermostat regulates flow and builds pressure. If you don't have the thermostat, mabye there's no pressure that is building within the block.
I am saying that when it gets hot, the thermostat opens. Usually the problem exists because people's thermostat are broken.
It could be the fact that you have no thermostat, so no pressure is building so no Flow can be circulated.
You're water pump, pumps the antifreeze all around. You may have flow, but no PSI (Pressure).
Flow + thermostat(blockage) = Presure. That is my reasoning for why you should put a new thermostat.
If it tures out that it's not the thermostat, then hey, at least you installed a new thermostat, right?
1. take out the radiator (run the garden hose to it, and see what comes out the other end.
2. Run the garden hose to the block...see what comes out.
3. Check for leaks and pinched lines.
4. Put in new thermostat.
If you do these 4 step, I'll be damn if it's not fixed.AND THERE'S NO OTHER EASY WAY TO DO IT. THIS WOULD SAVE MORE TIME THAN TRYING TO FIND THE PARTICULAR ENTITY.
Re: what would cause extreme coolant pressure in the block (Duce40sx)
Look, you guys are still missing the fact that any pressure beyond 16psi gets blown off by the radiator cap.
The water pump will not build any pressure, it's just an impeller using centrifugal force to move the water. The water pump is not a positive-displacement pump, so it will not build any hydraulic pressure. You could probably clamp off the upper radiator hose altogether and the block will not see more than 1psi. Same if the radiator was 100% plugged. Any pressure the WP would try to build would flow back behind the impeller.
To illustrate, when you put a box fan in the window of a bedroom with the door closed, does it build up pressure inside the room? No. But if the door is open it can FLOW a lot of air. Same with a water pump.
Back to the car. If you are sure that you are building up more pressure in your engine than the 16psi the cap is supposed to release at, spend $10 on a new Stant cap and see what it does. But you can't get around the fact that if the plugs leak at less than 16 lbs they need to be replaced, and if they are experiencing higher than 16psi you need a new rad cap.
The water pump will not build any pressure, it's just an impeller using centrifugal force to move the water. The water pump is not a positive-displacement pump, so it will not build any hydraulic pressure. You could probably clamp off the upper radiator hose altogether and the block will not see more than 1psi. Same if the radiator was 100% plugged. Any pressure the WP would try to build would flow back behind the impeller.
To illustrate, when you put a box fan in the window of a bedroom with the door closed, does it build up pressure inside the room? No. But if the door is open it can FLOW a lot of air. Same with a water pump.
Back to the car. If you are sure that you are building up more pressure in your engine than the 16psi the cap is supposed to release at, spend $10 on a new Stant cap and see what it does. But you can't get around the fact that if the plugs leak at less than 16 lbs they need to be replaced, and if they are experiencing higher than 16psi you need a new rad cap.
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tramp_drift240
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Re: (TheOne)
im gonna try that stuff, and im gonna do a compression test, but i dont know how to do a leakdown test.
i know i need to replace the freeze plugs, obviously. the damn things are leaking. and i know that i need to check my radiator cap, but im positive that just replacing the cap isnt gonna fix the problem.
im gonna be getting a new battery when i come back from a weekend trip, then ill be able to do the compression test. im still gonna flow test the block and the radiator, but theres gotta be something thats causing pressure to build up.
everyone keep trying to think what could cause this, what i should do, someone explain how to do a "leak down test"
ill come back and post my results after i do the compression test and a few other things. this has to be fixed by mid january.
NOT RELEVANT AT ALL, BUT:
my license was supposed to be suspended until March 28, but the court clerk messed up on the paperwork for the 90 suspended that was supposed to be tacked onto the six months i was already doing, and it turns out i can get my license back JANUARY 13!
so thats my deadline. i want my car running reliably by then.
i know i need to replace the freeze plugs, obviously. the damn things are leaking. and i know that i need to check my radiator cap, but im positive that just replacing the cap isnt gonna fix the problem.
im gonna be getting a new battery when i come back from a weekend trip, then ill be able to do the compression test. im still gonna flow test the block and the radiator, but theres gotta be something thats causing pressure to build up.
everyone keep trying to think what could cause this, what i should do, someone explain how to do a "leak down test"
ill come back and post my results after i do the compression test and a few other things. this has to be fixed by mid january.
NOT RELEVANT AT ALL, BUT:
my license was supposed to be suspended until March 28, but the court clerk messed up on the paperwork for the 90 suspended that was supposed to be tacked onto the six months i was already doing, and it turns out i can get my license back JANUARY 13!
so thats my deadline. i want my car running reliably by then.
Re: (tramp_drift240)
My bet is just on the freeze plugs being installed wrong. The only other possibilitys for increased pressure would be blocked coolant passages in the block, a blown headgasket...and well thats almost it. What couldve happened is when you got your block cleaned, is if they hottanked it, there could be dirt and debris that was dislodged, and not cleaned out from the passages, so it could be creating a lot of resistance in the block. Or, they decided to reverse flush the block, which if you had excessive scaling in the coolant passages, it would dislodge that, and it could cause the extra pressure. After all, like others in the thread have said, waterpumps create flow, -not- pressure. Pressure is created by the -resistance- to flow.
And, believe it or not, radiator caps do make a difference in your cars cooling. Its really often over looked, and usually causes higher engine temps when they stop working properly. So, if your car starts running slightly hotter then normal, and everything is still in working order...it is most likely the cap. Most people dont notice if that slight raise in temperature occurs, because of the extreme vaugeness of stock coolant temp gauges.
And...really, put a new thermostat in. Theyre really key in keeping your car at the proper operating temperature. Believe it or not, you dont want your engine as cool as you can possibly have it. It needs heat to expand parts, and let them seal as completely as they can. The cooling systems job is to -maintain operating temperature-...not simply keep everything as cold as possible. Engine temps that are too low are just as inefficent, and bad for your engine as engine temps that are too high.
And, believe it or not, radiator caps do make a difference in your cars cooling. Its really often over looked, and usually causes higher engine temps when they stop working properly. So, if your car starts running slightly hotter then normal, and everything is still in working order...it is most likely the cap. Most people dont notice if that slight raise in temperature occurs, because of the extreme vaugeness of stock coolant temp gauges.
And...really, put a new thermostat in. Theyre really key in keeping your car at the proper operating temperature. Believe it or not, you dont want your engine as cool as you can possibly have it. It needs heat to expand parts, and let them seal as completely as they can. The cooling systems job is to -maintain operating temperature-...not simply keep everything as cold as possible. Engine temps that are too low are just as inefficent, and bad for your engine as engine temps that are too high.
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tramp_drift240
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Re: (MicroMNky)
i appreciate you repeating just about everything ive already been told in this thread.
ill get to that stuff later, like the thermostat and what not, because i know for a fact you can operate a vehicle normally without a thermostat in place.
sure, ill put one in later on AFTER i figure out whats causing this problem.
ill check the cap, i said that. but i know for a FACT the pressure and the leaking isnt from improper installation. its starting to become a slam to my capabilities saying again and again that i did it wrong, when i did everything youre supposed to do when installing freeze plugs.
theres another variable thats causing this to happen.
the hot tank thing i already brought up, blocking passageways and what not.
thats why im taking the above advice and im gonna run a hose into the water inlet so i can try to see how much resistance there is in the block.
PLEASE. if you're just going to repeat whats already been said, dont bother posting. i realize you guys are trying to help, and i greatly apprectiate it, but its nice to get new information and new ideas instead of having the same ones said repeatedly.
ill get to that stuff later, like the thermostat and what not, because i know for a fact you can operate a vehicle normally without a thermostat in place.
sure, ill put one in later on AFTER i figure out whats causing this problem.
ill check the cap, i said that. but i know for a FACT the pressure and the leaking isnt from improper installation. its starting to become a slam to my capabilities saying again and again that i did it wrong, when i did everything youre supposed to do when installing freeze plugs.
theres another variable thats causing this to happen.
the hot tank thing i already brought up, blocking passageways and what not.
thats why im taking the above advice and im gonna run a hose into the water inlet so i can try to see how much resistance there is in the block.
PLEASE. if you're just going to repeat whats already been said, dont bother posting. i realize you guys are trying to help, and i greatly apprectiate it, but its nice to get new information and new ideas instead of having the same ones said repeatedly.
Re: what would cause extreme coolant pressure in the block (carbully)
Sorry to go a bit off-topic, but I thought I might add to this:
The assumption that coolant will be at 200deg in both cases seems to ignore that the coolant will have less time to absorb heat from within the engine. Hence, the coolant in an engine without the T-stat should have a lower temp before it reaches the radiator. One might then argue: "The lower coolant temp proves that the engine is retaining more heat!" This, too, would be incorrect. Since the velocity or mass flow of coolant is greater, you're still absorbing roughly the same amount of heat. You'd probably get more heat into the coolant since the heat exchange in the t-stat-less engine will have a higher temp differential throughout the entire engine.The above will carry over to the radiator. If coolant is flowing through the radiator twice as fast, twice as much coolant will run through the radiator, dissipating about the same amount of heat over time.
The most logical explanation for cases where people claim adding a thermostat fixes an overheating issue would be an inefficiency with the coolant pump. If, by some chance, the coolant pump cannot support the volume flow of an empty thermostat housing, the pump might cavitate or acheive less overall flow.
From experience, this is not the case with a 240sx.
To the OP:Run an expansion tank. Coolant expands when it's hot. This expansion dumps coolant into the expansion tank (hence the name). When the engine is turned off, the coolant contracts. This contraction creates a vacuum due to less coolant being in the system. The check-valve in the cap then sucks coolant in from the expansion tank. Without it, you'll just suck air back in, and we all know that air doesn't belong in your coolant galleys.
My bet for your initial problem is a damaged or gouged freeze plug, either on the hole or plug. Take care when replacing them. If they're all installed correctly, they won't leak, regardless of other issues. If they were damaged, it wouldn't take much for them to dump coolant out under pressure.
I'm not going to say it's impossible for an engine to overheat without a t-stat, but your explanation leaves out a few important variables.carbully wrote:Also, this may sound strange, but not running a t-stat can actually make a car run too hot. You guys will propbably flame me for that statement, but I am an ASE certified technician with over 21 years of experience. The thermostat serves an importaint role in regulating the speed coolant flows through the radiator. Having coolant flow too fast through the radiator does not give it enough time to dissipate enough heat into the air. So, if you have say 200deg coolant coming in to the radiator, and it passes through the radiator in only 2 seconds it has only had enough time to get rid of "x" number of BTU of heat, leaving the radiator at say 175deg.
Slowing down the flow, it spends more time in the radiator. So let's say now it spends 4 seconds iflowing through the radiator that's going to get your outlet temp down to say 160 deg. Make sense? To some of you it won't, becuase I have this argument even with other technicians. All I know is that I have seen it and fixed it by simply installing a missing thermostat.
The assumption that coolant will be at 200deg in both cases seems to ignore that the coolant will have less time to absorb heat from within the engine. Hence, the coolant in an engine without the T-stat should have a lower temp before it reaches the radiator. One might then argue: "The lower coolant temp proves that the engine is retaining more heat!" This, too, would be incorrect. Since the velocity or mass flow of coolant is greater, you're still absorbing roughly the same amount of heat. You'd probably get more heat into the coolant since the heat exchange in the t-stat-less engine will have a higher temp differential throughout the entire engine.The above will carry over to the radiator. If coolant is flowing through the radiator twice as fast, twice as much coolant will run through the radiator, dissipating about the same amount of heat over time.
The most logical explanation for cases where people claim adding a thermostat fixes an overheating issue would be an inefficiency with the coolant pump. If, by some chance, the coolant pump cannot support the volume flow of an empty thermostat housing, the pump might cavitate or acheive less overall flow.
From experience, this is not the case with a 240sx.
To the OP:Run an expansion tank. Coolant expands when it's hot. This expansion dumps coolant into the expansion tank (hence the name). When the engine is turned off, the coolant contracts. This contraction creates a vacuum due to less coolant being in the system. The check-valve in the cap then sucks coolant in from the expansion tank. Without it, you'll just suck air back in, and we all know that air doesn't belong in your coolant galleys.
My bet for your initial problem is a damaged or gouged freeze plug, either on the hole or plug. Take care when replacing them. If they're all installed correctly, they won't leak, regardless of other issues. If they were damaged, it wouldn't take much for them to dump coolant out under pressure.
Re: (tramp_drift240)
Use a Rubber Mallet. Works about 90% of the time.
Re: (Duce40sx)
AceInHole, you are probably right in theory. You obviously have more 240sx experience than I do. I do not even have a 240 yet, and just joined the forum to gain experience with them before I buy.
I do not have a firm grasp on the thermodynamics involved. It would seem to me that you would be right about the coolant taking on less btu in the block if it is less restricted, so in theory the btu transfer differential between restricted and unrestricted should be equal for taking on heat in the block and giving up heat in the rad.
In real world experience, however (21 years, ASE certified technician) I have seen cars overheat due to a lack of a t-stat. Never seen it on a 240sx, though so I defer to your experience on that.
I do not have a firm grasp on the thermodynamics involved. It would seem to me that you would be right about the coolant taking on less btu in the block if it is less restricted, so in theory the btu transfer differential between restricted and unrestricted should be equal for taking on heat in the block and giving up heat in the rad.
In real world experience, however (21 years, ASE certified technician) I have seen cars overheat due to a lack of a t-stat. Never seen it on a 240sx, though so I defer to your experience on that.
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tramp_drift240
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Re: (Duce40sx)
so even if theres something wrong with my coolant system, as long as i have my plugs installed correctly and everything, they shouldnt leak?
ive still got to figure out whats going on with my system before replacing them again, because if i replace them and they pop out again, im gonna be super pissed since i have to take it to a dealer this time to get 'em changed.
ive still got to figure out whats going on with my system before replacing them again, because if i replace them and they pop out again, im gonna be super pissed since i have to take it to a dealer this time to get 'em changed.
Re: (tramp_drift240)
I've had plenty of overheating issues, even head lift warping a headgasket. Coolant dumped out of the 1.3 bar (roughly 18psi) radiator cap, as it should. I've NEVER seen coolant leak from a properly installed freeze plug. By nature they should self seal under pressure.
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tramp_drift240
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Re: (AceInhole)
self seal under pressure? how would that happen with their design.
im gonna have to find out how much it would be to get them replaced at the dealer since i cant do it.
im gonna have to find out how much it would be to get them replaced at the dealer since i cant do it.
hey guys sorry asking the same questions but im hoping one of you can diagnose the problem i have.. ill be as specific as possible. i think its the head gasket but i just need confirmation
before i bought a new rad. cap i had overheating problems and coolant was spilling out from the overflow tank. when i off the engine it sounds like bubbles going into the OFT.
after i bought rad cap overheating stopped but spilling persisted. i've bled the car many times and each time i take it for a drive the coolant overflows
-overflow tank has a hint of fuel smell and black specs in bottom (never done a complete flush so could be dirt could be oil)-radiator coolant does NOT smell like fuel-NO oil in coolant/coolant in oil-engine runs well
would testing the compression be the best thing to do? thanks
before i bought a new rad. cap i had overheating problems and coolant was spilling out from the overflow tank. when i off the engine it sounds like bubbles going into the OFT.
after i bought rad cap overheating stopped but spilling persisted. i've bled the car many times and each time i take it for a drive the coolant overflows
-overflow tank has a hint of fuel smell and black specs in bottom (never done a complete flush so could be dirt could be oil)-radiator coolant does NOT smell like fuel-NO oil in coolant/coolant in oil-engine runs well
would testing the compression be the best thing to do? thanks