QuestionQUESTION: I am having the same problem as the gentleman you answered on 3/04/11. I have a 2005 town and country 3.8L with no egr valve system it is running like it is on 3 or 4 cylinders. I replaced spark plugs, wires, coil pack and cam sensor still doing the same. All cylinders have 150lbs of pressure except #5 which is fluctuating between 25lbs and 90lbs.
ANSWER: Hi David,
It is good that you took the pressure readings which discovered the lower that normal compression of cylinder #5. Did you happen to notice any excess wetness of the plug when you removed it or on the pressure gauge? That would be a sign of the head gasket leak around that cylinder. A valve that is sticking ajar or has a damaged seat/edge will cause that as well.
You could check for coolant in the combustion chamber by pulling the plug and have a helper crank it while you watch for any expulstion of fluid from the hole. Then you might check the valve action by removing the valve cover and observing when the engine is cranked over. Let me know and I can give you the step necessary to remove the valve cover.
I'll let you know if I think of something else to check.
Roland
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QUESTION: There was no moisure of water in the cylinder that I could see. Could it be a broken rocker arm support. I read on an earlier post from a Chrysler mechanic....."The rocker arm support on top of the head (under neath the valve covers) can and although rare, break off from the head! This will leave the rocker shaft without the end support and it will flex up and down enough when opening the valves to rattle. It will eventually break the rocker shaft and cause that cylinder to miss." Could this be the problem?
ANSWER: Hi David,
Sure sounds like that is one possibility as that would be near #5, but only inspection will tell you. To do that:
Remove the wiper module. Remove wiper arms, remove cowl cover, remove posilock on the electrical connect plug/socket, remove washer hose from outside of covering, disconnect drain tubes from nipples on bottom of module, remove 2 nuts holding module to lower windshield fence, remove 2 bolts that hold module to dash panel, remove module from studs (note: don't let module rest on brake master cylinder reservoir).
Remove spark plug wires
Disonnect power steering pump supply hose support clip from cylinder head cover
Disconnect PCV valve from cylinder head cover
Remove cover bolts
Remove cover and gasket.
Install is the reverse. The cover bolts have a torque limiter sleeve and seal and must be replaced as a unit if needed. Torque bolts to 105 inch-pounds (~ 8.5 foot-pounds).
Please let me know what you learn.
Roland
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QUESTION: It was a broken valve spring at the #5 intake valve. What do you think would cause this? And do you think a simple spring replacement would solve my problems? The rocker shaft and the pedestal all look good
AnswerHi David,
I have no idea what would cause this other than a manufacturing defect. It appears that replacing the spring may solve the problem as a procedure for that is described in the manual. A Miller tool No. 8453 is required as is a spark plug hole fitting that allows for the cylinder to be pressurized with the help of an air compressor. If you intend to do it yourself let me know an I can attach a couple of pages to an email from the manual. But you will need to tell me your email address via a 'private' option follow-up question. If you don't use the 'private' option the address is deleted from the message.
Roland
