need input on noise situation

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Sep 21, 2005 | 08:06 PM

96f150

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Fleet Mechanic

Joined: Nov 2000

Posts: 1,713

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From: In my House

need input on noise situation

Ok, here it goes....96f1504x4, bought it with 79k on it, now has 154k on it, I maintain it really well. Compression check revealed 150-165psi. Maybe uses a quart every 3k. Problem is, once I change the oil(10w-40), and the oil is clean, once the oil gets warm, the truck almost souds like a diesel at idle. Been this way for about 10k or so. Sound is defintely coming from the bottom area, just really can't figure out what it may be..mains? wrist pin?. Truck doesn't skip a beat either, runs really well, just kinda scary in the stop=go traffic in the morning when you here that noise. Any advice from you guys I am thankful for.

Rich

Sep 22, 2005 | 09:29 AM

Kemicalburns

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Joined: Jul 2002

Posts: 14,285

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From: Bend,OR

whats your oil pressure. hook up a real mechanical gauge an let us know. are you sure its not a cracked exhaust manifold? take a broom stick and with motor running put it on the block and put your ear to the other end. it will act as a stethiscop and help you pin point the knock if there is one. also does it increase with rpms or go away?

Sep 22, 2005 | 12:34 PM

96f150

Thread Starter

Fleet Mechanic

Joined: Nov 2000

Posts: 1,713

Likes: 2

From: In my House

I did put a mechanical gauge in it a while back, it is around 12psi at idle. Once you bring it up a bit past idle, the noise goes away. It only happens once the oil gets warm though. Cold startup, you don't here it at all.
Thanks
Rich

Sep 22, 2005 | 02:52 PM

Kemicalburns

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Joined: Jul 2002

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From: Bend,OR

12 psi at idle is low so it sounds like you have worn main bearings. try running some 20-50w oil an see if that helps. otherwise your looken at a bottem end rebuild

what oil filter are you using. if its a fram take it off right away and go with a purolator or motorcraft etc.. fram filters have been known to cause low oil pressure issues

Sep 22, 2005 | 05:03 PM

96f150

Thread Starter

Fleet Mechanic

Joined: Nov 2000

Posts: 1,713

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From: In my House

actually my gauge has been broken for a few months now, so I have the idiot light hooked back up...Would 20w50 be ok to run here in the winter time in Connecticut? I am worried it will be to thick and seize my oil pump shaft. What is a good psi at idle?

Sep 23, 2005 | 10:20 AM

Kemicalburns

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Joined: Jul 2002

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From: Bend,OR

at idle no lower then 20psi. 30-35 is nice. that oil might be a bit thick.
your not running synthetics are you?

Sep 23, 2005 | 12:01 PM

ssn randy

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Joined: Feb 2004

Posts: 423

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From: va beach VA

i run straight 30w in mine but also have the noise at start-up. stops after 1second, change the filter to the one recommended and that might help. oh 144k on mine.