2001 XLT Engine Knock

[hitman]

2nd post, here goes:

I've had my 2001 V8 AWD Explorer (20,000 miles) for about 2 weeks now. Just recently I've noticed that when sitting at idle the engine knocks slightly. Reading up in the owner's manual, it states that the engine is formulated to run with 87 octane and that occasional knocking may be heard. It goes on to state that this is normal, but should not be heard when the engine is under heavy load or acceleration.

I want to say that if the manual states this, then I shouldn't bother worrying about it. But, I'm used to my 1993 Mustang GT and never hearing knocking.

Is this as the manual states, normal?

Thanks for the input in advance.

 

[TPLYNCH]

There were reports that the last year(s) of the 5.0 were more prone to noises/problems because, since the engine was going out of production, the casts weren't properly maintained so the tolerances in the engine grew which led to more noises/leaks..... That being said, I hope you don't have one that will cause problems. My OHV 4.0 "diesels" at idle due to a redesign of the wrist pins... but Ford says it's ok and won't cause problems in the engine.

Does yours only do it at Idle when cold/on startup, or all the time. Use of Fram oil filters have been known to cause knocks on startup due to a poorly designed anti-drainback valve. (see oil filter study on top of page for more info about that).

 

[hitman]

Hmmm, that's an interesting thought on the 5.0 engine.

As for the knock itself, so far there is no pattern to it. Though, on startup, I haven't yet heard it. The 4 or 5 times I've heard it have been typically after driving 10-15 minutes around town and at different times of the day.

On a side note, I just changed the oil over the weekend and put in 5W-20 (per the owner's manual) and a Motorcraft oil filter. I had seen that oil filter study before on a Mustang-related forums site.

 

[TPLYNCH]

Hmmm, don't know what else I can add, except maybe search for "engine knock" and see what comes up. There have been other 5.0 owners asking about noises.... clicks and pings. I doubt it has anything to do with the gas, since spark knock is under load and like you said, yours is doing it at idle.