No Compression No 1 Cylinder 1997 4.2l
#1
No Compression No 1 Cylinder 1997 4.2l
Hi, I had a short thread on part of this problem before I had done any additional investigation. I had basically conlcuded that I needed a rebuild or a replacement engine because it sounded so bad.
The truck has 308,500 miles on it. I replaced the timing-chain cover gasket a while back.
Well, this afternoon (finally quit raining) I pulled all the plugs and checked the compression on all the cylinders.
All but #1 were running 175 to 190 PSI. Forgot to hold the throttle down so not sure what effect this has on the results.
#1 has absolutely NO compression. The truck will run but sounds awful and some smoke coming out tail pipe. The spark plug shows NO evidence of coolant.
At this point, I am hoping it is only a blown head gasket. I am sure it could be a stuck valve or something else.
When I cranked it during the compression test, I heard no racket inside the motor.
Would a blown head gasket give NO compression or is it time to just go for a replacement in which case they want the intake, etc left on?
Thanks!! Mark
The truck has 308,500 miles on it. I replaced the timing-chain cover gasket a while back.
Well, this afternoon (finally quit raining) I pulled all the plugs and checked the compression on all the cylinders.
All but #1 were running 175 to 190 PSI. Forgot to hold the throttle down so not sure what effect this has on the results.
#1 has absolutely NO compression. The truck will run but sounds awful and some smoke coming out tail pipe. The spark plug shows NO evidence of coolant.
At this point, I am hoping it is only a blown head gasket. I am sure it could be a stuck valve or something else.
When I cranked it during the compression test, I heard no racket inside the motor.
Would a blown head gasket give NO compression or is it time to just go for a replacement in which case they want the intake, etc left on?
Thanks!! Mark
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Hey GLC, I got the rocker-arm cover off (you can tell its killing me to have to pay for a rebuild or replacement) and the rocker-arm for the intake valve on No. 1 has a lot more play in it when the valve is closed then any of the others on down the line. Checked the torque on the bolt and it was fine.
Am going ahead and taking off the head and see what is up. If it turns out I have a burnt valve or it is stuck, whatever, what all can be done to a head to get it back into serviceable shape and how much can one expect to pay?
Are the valve guides replaceable?
Thanks for your help. It is taking me a while to do this because of other things I have to do and pretty much have to work on it outside -- keeps freakin raining.
Mark
Am going ahead and taking off the head and see what is up. If it turns out I have a burnt valve or it is stuck, whatever, what all can be done to a head to get it back into serviceable shape and how much can one expect to pay?
Are the valve guides replaceable?
Thanks for your help. It is taking me a while to do this because of other things I have to do and pretty much have to work on it outside -- keeps freakin raining.
Mark
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LOL Hey Guys, yeah, my truck is like an old friend.
Anyway, got the lower intake manifold off finally, going to try to take the head off tomorrow. It definitely appears that I have a bent valve on #1 intake -- it is about 1/10 - 1/8 inch short of coming all the way up when closed. So here is the next question. While I have all this stuff tore off, what is the best way to clean all the carbon off the springs, lifting rods, etc? Would a wire brush mounted on a bench grinder damage the parts and can the valve guides be cleaned out?
I also recall seeing there are new torque specs on the intake manifold. I have a Chilton manual, so have no idea if they are right and if the torque specs for the head in the book are right.
Well, one thing is for certain, going to finally get the lower intake manifold gasket replaced. LOL
Any suggestions on the best RTV sealant to use?
Thanks!!! I was looking forward to 400,000 myself.
Anyway, got the lower intake manifold off finally, going to try to take the head off tomorrow. It definitely appears that I have a bent valve on #1 intake -- it is about 1/10 - 1/8 inch short of coming all the way up when closed. So here is the next question. While I have all this stuff tore off, what is the best way to clean all the carbon off the springs, lifting rods, etc? Would a wire brush mounted on a bench grinder damage the parts and can the valve guides be cleaned out?
I also recall seeing there are new torque specs on the intake manifold. I have a Chilton manual, so have no idea if they are right and if the torque specs for the head in the book are right.
Well, one thing is for certain, going to finally get the lower intake manifold gasket replaced. LOL
Any suggestions on the best RTV sealant to use?
Thanks!!! I was looking forward to 400,000 myself.