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4.0l woes

K

killer98xjsport

NAXJA Forum User
Location
Portland Oregon
Last year i installed a remanufactured engine. 12000 miles later it has a rod knock. From break in only used royal purple oil. The engine has a warrenty but will have to have it removed and shipped to the reman company. Wondering if anyone thats done rod and main bearings can give me a general ideal of cost and how well its held up?? I know parts are cheap just try to see if it will be easyer for me to fix. I am starting to hate the 4.0l. Not as strong as I thought.
 
I replaced my rod bearings last week.. cost me $45ish in parts. $32 something for the bearings and then the pan gasket was $15ish.. Don't buy the bearings until you get them old ones out so you can verify they are std size. They should be stamped "STD" or ".10" ect. It's a pretty easy job, you can use rear main seal replacement threads as a guide for removing the oil pan.
How does your oil pressure look? I don't see how one of the bearings could have gone bad so quickly.. maybe the crank has been turned and it was made undersize.. making the bearing tolerance/gap too wide.
 
I am getting ready to break in my new engine after a rebuild. I have never heard of using Dino oil. I have heard of not using synthetic though. Who'd want to anyway? Its more expensive and it only stays in for a few hundred miles.

What is Dino oil?
 
Last edited:
Break in with non-detergent 30W + ZDDP. Change at 300 & 600 miles. At 1500 miles go synth +ZDDP if you want.
 
I used Brad Penn 30w Break-in Oil for the cam break-in and the first 600mi. Now I'm using their 10w30 "racing oil"(due to higher Zn content: 1300-1400ppm, cause it'd have to be below 800 to be considered "standard/on road use"). Dino oil is recommended for the proper seating of the rings; however, I do believe certain vehicles come from the factory with synthetic(maybe special break-in formulation or they already drained a panful and refilled).
 
killer98xjsport said:
Last year i installed a remanufactured engine. 12000 miles later it has a rod knock. From break in only used royal purple oil. The engine has a warrenty but will have to have it removed and shipped to the reman company. Wondering if anyone thats done rod and main bearings can give me a general ideal of cost and how well its held up?? I know parts are cheap just try to see if it will be easyer for me to fix. I am starting to hate the 4.0l. Not as strong as I thought.
Click to expand...

does it knock under load or just at idle. if only at idle its not a problem.

have you ruled out a cracked flex plate
 
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