Pressurized coolant quandary
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TECH Junkie
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Pressurized coolant quandary This is not happening to my motor, but another person I know. It's a studded ls motor with ls9s.... heads torqued to 80ft/lb. He thinks he's lifting the heads.....I think not. At 20psi and 13 degrees....I don't believe he's making enough cylinder pressure to lift the heads. He's verified the timing with a light, so it's doing as it's commanded. The car runs good, went 6.29 @119 on 12psi......8.74 @155 running out of gear on 20.5psi. Personally I think it's a cracked sleeve, he thinks not. ..because of no water in the oil. My logic is, cylinder pressure will prevent water getting into the hole while running..... but will seal up enough to not leak in when shut off. Thoughts?
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TECH Junkie
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Oh, and here's another thing. He pulled the plugs, and there's no signs of coolant in any of the holes. Even went so far as to pull the heads, every hole is fine. After he told me that, I was completely stumped. I could see if he was running big boost on 20 degrees, but as it is now..... it's just not adding up.
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From: Norn Iron
has it ever ran correctly and reliably ?
What sort of pressures is he seeing in the cooling system and when ? If he cant log, just hook up a cheap gauge to a high location on the rad/header, preferably in air.
What sort of pressures is he seeing in the cooling system and when ? If he cant log, just hook up a cheap gauge to a high location on the rad/header, preferably in air.
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TECH Junkie
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He's had issues with the build ever since its been completed, which was about 3 weeks ago. With that said, it's the same block that he was using a couple of seasons ago.... just dropped in a junkyard motor in the interim till he could afford this big build. So it's just been sitting, but yes it was fine when he was running it....although it was just a heads cam car at the time. He hasn't logged coolant system pressure as of yet.
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Oh, and here's another thing. He pulled the plugs, and there's no signs of coolant in any of the holes. Even went so far as to pull the heads, every hole is fine. After he told me that, I was completely stumped. I could see if he was running big boost on 20 degrees, but as it is now..... it's just not adding up.
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From: Norn Iron
As a new unproven build...it could simply be a bad cooling system arrangement, lack or airflow or indeed something engine related.
The fact the block has been used before without issue should at least give some hope that is not the problem
The fact the block has been used before without issue should at least give some hope that is not the problem
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Yup, went back with fresh gaskets... and it's still pushing water. This is what's making me lean towards a bad sleeve. But I have no experience with one that's split, so it's tough for me to say really, although truckdoug said his weeped in when he had one go bad.
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if it had a bad sleeve you should know pretty fast i broke a sleeve at 30lbs on my other car it put so much pressure in the coolant system it blew the hoses off . i would just go double check everything makes sure the t stat is good fans are working and are blowing the right way ive done that before turn the fan on and the car would get hotter and then just make sure its fully blead
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Took a really long time to bleed my build . It was doing the same thing. Finally I filled it through the top hose and attached a lisle funnel and let it run forever while squeezing the hoses. Some are just harder to bleed than others, especially if it’s been all apart
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TECH Junkie
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Agreed. I had that issue when I put mine back together. But with his setup, he's not running a tstat... so it shouldn't be as hard to purge.
anyone you know got a vacuum filler? i made it like 35 years without a cooling system bleed issue then I bought a ******* bmw and now all my **** has problems bleeding. ****** bmw cursed me man. bought the vacuum fill kit and **** is alright in my world once again.
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From: Mechanicsburg, PA
Buy a Lisle 75500 or equivalent combustion tester and confirm or eliminate whether it has combustion gases in the cooling system. They are cheap and readily available. If no gases, get/borrow the vacuum tool and fill it. No thermostat is not a guarantee the system doesn't have trapped air.
Buy a Lisle 75500 or equivalent combustion tester and confirm or eliminate whether it has combustion gases in the cooling system. They are cheap and readily available. If no gases, get/borrow the vacuum tool and fill it. No thermostat is not a guarantee the system doesn't have trapped air.
thats awesome. had no idea. ordered it.
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From: Mechanicsburg, PA
Advantages to being an Auto Tech for so many years. One other trick for everyone. The fluid (usually blue in color) changes to yellow or green in the presence of combustion gases. If you remove the tester from the area and keep pumping the bulb it will change back to blue and can be reused. I keep it in a separate container so I know it is used. But have had no issues reusing it.
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TECH Junkie
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Advantages to being an Auto Tech for so many years. One other trick for everyone. The fluid (usually blue in color) changes to yellow or green in the presence of combustion gases. If you remove the tester from the area and keep pumping the bulb it will change back to blue and can be reused. I keep it in a separate container so I know it is used. But have had no issues reusing it.
What block?
When my iron 6.0 cracked it didn't leak period water into the cylinder
It stayed completely sealed up unless it was under power then it would open up
You could drive around just fine with no issues or symptoms. Make a hit and you could push a gallon into the overflow in a 1/4 mile
It's tough to see the crack unless you are looking for it.
You can test for combustion gas in the coolant with a CO detector and a ziplock bag in 2 seconds
When my iron 6.0 cracked it didn't leak period water into the cylinder
It stayed completely sealed up unless it was under power then it would open up
You could drive around just fine with no issues or symptoms. Make a hit and you could push a gallon into the overflow in a 1/4 mile
It's tough to see the crack unless you are looking for it.
You can test for combustion gas in the coolant with a CO detector and a ziplock bag in 2 seconds