4.0 "knock" question???

I picked up a CLEAN "89 Laredo with 218K on it.The motor runs great,has no smoke and good oil preasure.When you first start it in the morning,you can hear a loose rod knock for a few seconds.The guy i got it from owned it for 2 years and it has always done it.I'm hoping to drive it until spring and maybe put bearings in it???Should i be worried about it???I'm very easy on it and won't be beating the crap out of it.Also,can you pull the pan and put bearings in these motors or would it be to tight?Any recomendations would be great.This XJ has NO ROT at all,so i really want to keep it.Finding anything this clean around here is a real challenge!

Probably not rod knock. Being it is only on start up I would say its a lifter bleeding down or piston slap.

Sounds like rod knock to me. That's when the Renix motors give rod bearing warnings, the initial flare on startup before the oil pressure builds and idle speed stabilizes.

Pan removal difficulty varies with lift height. Assume the worst and disconnect the track bar, lca's and so on to get the pan out, then it's an easy job to change the rod bearings, check the mains and replace rear main seal, new pump, upgraded one piece pan gasket.

Thanks,i NEED to nurse it for a while.What oil should i run for the winter?I was going to add lucas also,good/bad idea???

i have the same problem. knocks when i start it up and or when ever i rev it hard.

If you need to nurse it for awhile might I suggest that you pull the oil pan and re-torque the rod and main caps--they are notorious for working loose.

joe_peters said:

If you need to nurse it for awhile might I suggest that you pull the oil pan and re-torque the rod and main caps--they are notorious for working loose.

Click to expand...

Problem is,i don't have a garage or the time to do it myself at this time.