View Full Version : 99 f250 5.4 2v engine knock

September 4th, 2019, 07:35 PM
192k. Unplugged the cop individual with no sound change. Knock comes and goes at idle but if the ac kicks on or put in gear it goes away.when put back in park or ac shuts off it comes back. Hit the gas in park or gear knocks there.


September 4th, 2019, 08:54 PM
If it only knocks when the A/C compressor is not running, it's probably the compressor clutch.

September 4th, 2019, 09:08 PM
When ac compressor kicks on or when put in gear engine idles down so no knock.when engine revs over 1k the knock is there

September 4th, 2019, 11:54 PM
As a test, pull the drive belt for a couple minutes and see if it still knocks. If it doesn't, it's something that's driven by the belt. Use a stethoscope to try to find the source.

September 6th, 2019, 08:15 AM
If a main bearing is bad will it still have good oil pressure cause cold and normal temp pressure was still good

September 6th, 2019, 07:02 PM
Engines pulled..bearings look good.i did find what looks to be some type of brown plastic thats broke and i found it between the last main bearing cap and rear main seal housing.i dont know what it could be.
It looks like the same thing the oil pick up tube is made out of but nothing looks broke on it

September 10th, 2019, 02:47 PM
This is what i found
Pics didnt post.does it take time for them

September 10th, 2019, 03:24 PM
You have to resize your images. 244kb max file size.

September 10th, 2019, 03:55 PM
Try these pics

September 22nd, 2019, 03:29 PM
Took the motor back out cause had the same knock. Found one of the rod bearings spun.so having the crank turned and that one rod resized.
Few questions:
How to i check the piston pins to make sure there still good?
When i buy new rod bolts if i get arp is there anything special that needs to be done to install them?
Where is the cheapest place to get oem main and rod bolts? (Modmax?)