Unknown knocking sound
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Unknown knocking sound
I have a weird sound coming from somewhere in the engine/tranny area, and I am trying to diagnose it. I happened to find this statement on another forum, and I was wondering if anyone here can confirm this from their experience:
"They are decent motors and can be built to make good power, but they have known oiling deficiencies...get in a truck or car with a 351M/400 in it that has some mileage (75k+ miles) on it, and more times than not, after the oil gets hot, you'll hear some bottom end (main bearing or connecting rod) knock. The oiling problems can be resolved, fairly easily, during a rebuild."
Also, how would a person solve this oiling problem during a rebuild?
"They are decent motors and can be built to make good power, but they have known oiling deficiencies...get in a truck or car with a 351M/400 in it that has some mileage (75k+ miles) on it, and more times than not, after the oil gets hot, you'll hear some bottom end (main bearing or connecting rod) knock. The oiling problems can be resolved, fairly easily, during a rebuild."
Also, how would a person solve this oiling problem during a rebuild?
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I would be more concerned with pin-pointing the cause of the "noise" rather than read about some issue that may or may not have anything to do with your problem.
It could be something as minor as loose torque convertor bolts, but you need to narrow it down.
Did the truck just recently start doing this or has it been a problem for as long as you have owned the truck?
We need more details...
Josh
It could be something as minor as loose torque convertor bolts, but you need to narrow it down.
Did the truck just recently start doing this or has it been a problem for as long as you have owned the truck?
We need more details...
Josh
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Joined: Jan 2006
Posts: 1,779
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From: Waterloo IL
I would be more concerned with pin-pointing the cause of the "noise" rather than read about some issue that may or may not have anything to do with your problem.
It could be something as minor as loose torque convertor bolts, but you need to narrow it down.
Did the truck just recently start doing this or has it been a problem for as long as you have owned the truck?
We need more details...
Josh
It could be something as minor as loose torque convertor bolts, but you need to narrow it down.
Did the truck just recently start doing this or has it been a problem for as long as you have owned the truck?
We need more details...
Josh
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Ive owned it for several months now, and its likely that its had it for the entire time (every day is a new adventure in finding more stuff to be fixed), but I couldn't say for sure because I wasn't really paying attention... too many new noises for me. So.... at least a few months.
I only notice it driving uphill or accelerating with more than a light foot on the pedal. I don't hear it when Im cruising downhill, or on straight and level. It seems like it is a higher engine load issue.
BTW, Im driving a 79 F150 351m, 4wd, automatic
I only notice it driving uphill or accelerating with more than a light foot on the pedal. I don't hear it when Im cruising downhill, or on straight and level. It seems like it is a higher engine load issue.
BTW, Im driving a 79 F150 351m, 4wd, automatic
Last edited by physicsguy11; Jul 24, 2010 at 04:43 PM. Reason: forgot to answer a question!
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From: Western N.C.
It definitely sounds to me like it's pinging, not knocking. Knocking indicates a physical mechanical issue...pinging is a fuel/ ignition issue.
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