Can anyone tell me what "rod knock" is? How can I tell if my truck has this problem? Would you hear this constantly or if your putting your engine under a load
( Hills,towing )? Could this be mistaken for detonation?

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98 F-250 LD E.C. 4x4,4.6 litre,K&N filter,tow pkg.,3.73rear,off-road pkg.,LT265/75R16

 

Rod knock occurs when the bearing in the big end wears out and you can hear the piston direction change via the resultant slop within the connecting rod-to-crank clearance.

It is a somewhat constant knaknaknaknaknaknaknakna that changes speed with engine rpm -- both up and down in speed.

Spark knock -- often described as 'marbles in a can' or 'ball bearings dropped in the (porcelean) bathtub' does NOT make noise upon deceleration -- only at (mostly part-throttle) acceleration.

You can often hear loose lower-end (rods -- many if not all of them) making a bdrdrdrdrdraaaaak upon cold-start on 10-yr-old GM V-6 engines -- which are oil-starved for the first one second upon start-up.

Rod knock is rare -- spark knock (aka pre-ignition) is not -- and is often reported as a symptom of oily mass-air-flow sensors (like where generously-oiled K&N filters are in use).

Does this help?

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Y2K™ Jim - N8JG@Hotmail.com

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Y2K,
Thanks for the info. I don't think I have rod knock.... probably detonation..Thanks!

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98 F-250 LD E.C. 4x4,4.6 litre,K&N filter,tow pkg.,3.73rear,off-road pkg.,LT265/75R16