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Cylinder Pressure problems


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Ok bit of a long story this? I suspect that my head gasket has gone, however last night I did a combustion test, of which the liquid stayed blue. Cool I thought, so then went on a did a pressure test. The front 3 cylinders were running at between 160 - 165 psi. Then did the back 3, which were running at 136 - 146. Now i know this is down, but all 3 running at the same? Is this usual. Some one I spoke to that the VR6 tends to bore the cylinders out of shape, which will lead to a new engine. I dont get any problems with it using oil and stuff. Is this a problem that others have experienced, Or is it more likely to be the head gasket.

Please help before i take it all apart.

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well, ive had lots of temp problems and stuff, The fan relay has gone due to water pressure causing the resivor to leak over the fuses. However the when fans are on the car dont overheat, which I thought would happen anyway if the HG is gone. Theres a few water leaks around the engine, but what I have noticed is that the upper waterpipe on the R side of the engine has lots of pressure, whereas the bottom Water pipe on the R side of the engine is stone cold with no pressure.

Oh and thanks for the welcome.

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Ok bit of a long story this?

A bit of a long reply but I hope it helps. :)

Have you changed your thermostat recently? If not I'd start there. If its only opening partially then it could be the cause of your water pressure and strange overheating problems. Hot & cold top & bottom hoses is a sure sign of poor circulation. As for the compression, did you do a cylinder leak test or compression test where you turn the engine over with the key? In the past I found these to be a bit innacurate. I have more faith in a cylinder leak test where compressed air is pumped into each cylinder individually when the piston is at TDC. All valves are shut but there will be a slight loss of air. A 20% loss of air being pumped in was acceptable from memory. If its any higher than that on any given cylinder then its a process of elimination. If you can hear air coming from the exhaust pipe = exhaust valve, air from inlet manifold = inlet valve, air form dipstick = rings, air/bubbles from water reservoir = cracked head or head gasket. Since the colour check stayed blue, I don't think its the latter.

What sort of mileage has it done?

Kevin

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is the water coming out of the expansion bottle`s little over flow on the side of the bottle? if so when my headgasket went this it what happen to me the car didnt over heat the temp gauge was normal there was a bit of excess white smoke (steam) from the exhaust due to the headgasket so all i had was the smoke and the water coming out of the bottle sound similar to mine when it went.

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Ok bit of a long story this?

A bit of a long reply but I hope it helps. :)

Have you changed your thermostat recently? If not I'd start there. If its only opening partially then it could be the cause of your water pressure and strange overheating problems. Hot & cold top & bottom hoses is a sure sign of poor circulation. As for the compression' date=' did you do a cylinder leak test or compression test where you turn the engine over with the key? In the past I found these to be a bit innacurate. I have more faith in a cylinder leak test where compressed air is pumped into each cylinder individually when the piston is at TDC. All valves are shut but there will be a slight loss of air. A 20% loss of air being pumped in was acceptable from memory. If its any higher than that on any given cylinder then its a process of elimination. If you can hear air coming from the exhaust pipe = exhaust valve, air from inlet manifold = inlet valve, air form dipstick = rings, air/bubbles from water reservoir = cracked head or head gasket. Since the colour check stayed blue, I don't think its the latter.

What sort of mileage has it done?

Kevin

[/quote']Its done about 103000. We will be changing the thermo at the same time. I think its gonna be a case of doing something and seeing if it gets rid of the problem. I presume that it feels a bit lumpy coz of the lack of pressure.

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