Hi All,

I have my motor tore down for a necessary head gasket job. The 4.0 has 153k on it.

I am having a hard time on deciding where to stop my scope of work. I have decided to also replace the radiator, water pump, oil pump, and timing chain/gears. In addition I am replacing coolant hoses, power steering lines, etc.

While I am in the motor should I replace the hydraulic lifters and the push rods? They aren't necessarily gummed up or failing. Its just hard to say where to stop, but I definitely don't want to be tearing it open again for something like a lifter in a year. Its about $200 more dollars for those parts - not a huge amount, but not insignificant. Basically I'm wondering is it potentially better to leave whats working, or are replacements pretty much a swap with no risk?

Anything else I should replace while I have it open? I appreciate any advise.

 

If there is no problem with the cam/lifters, I absolutely would not replace them. There are lots of quality control issues with flat tappet cams/lifters any more. Your original set is unlikely to fail as long as you keep your oil changed with a quality diesel oil.

 

I use Rotella 5w-40.

They seem to be fine. Wasn't sure if it would be 'preventative' to put a new set in. The quality question ran through my mind as well.

Thanks!

 

Agreed, the last thing you want is to break in a new cam and lifters. too much stress.

 

Cool - thanks for the quick answers!
Follow up question - Should I replace the CMP sensor and Oil pressure sensor when I do the timing chain?

 

Cover the CMP cover in aluminum foil, it will never fail again. Check your pulleys. Don't bother with cam, lifters, or rockers assuming you had no problems. Good time to relocate coils if you were considering it.

 

Ok, Ill bite on the aluminum foil. Whats that about?

If my CMP isnt bad, does replacing it make any sense? Like do they go bad from being old eventually or whats the story with them.

 

Heat from the exhaust and catalytic converter kills the crank position sensor over time. Shrouding it with heavy foil (e.g. dollar store baking tray) helps protect it.

 

Need to clarify: CMP = Cam Position sensor, CKP = Crank Position sensor. The CKP can get overheated by the exhaust downpipe. I do not recall reading about issues with the CMP. I think that is the sensor the original poster is asking about.

 

Yes, I am talking about the CMP on the front timing cover. Is it a good idea to replace that?