The 5.0 V8 engine on my 1990 F-150 suddenly started making very loud banging and pinging noises when driving on the freeway the other day, then it died when I got off the freeway and stopped at a light. Once it dies, it will start again if I let is sit for a few minutes. The engine has 180K miles on it. I have checked the oil level, oil pressure gauge reads fine, and I have been using regular shell or chevron for the last 300 miles before this happened. I have a video on youtube of the engine running, please check it out and I would love some help on how to diagnose and fix this problem.

YouTube - 1990 F150 5.0 V8 engine clanging.MPG



Thanks!

PS I am new to the board and look forward to being part of this forum!

 

Wowsa, that sounds bad. Have you checked to make sure that all of your spark plugs are tight. Kinda reminds me of a car we had in a shop class years ago that we ran with one spark plug out.

If it's not that, it sounds expensive. I'm thinking spun rod bearing.
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Oh, By the way, Welcome to FTE. I think you'll find it a wealth of information.

I appreciate the Youtube video, it makes things a lot easier to diagnose. Describing a sound can be really hard.

Also, because I love equipping people with more knowledge about their trucks... The oil pressure gauge on these trucks pretty much only reads on/off. If it ever drops, either you have a bad sending unit or your engine is due for a new oil pump like yesterday. This is something to consider as the truck get's older, because it may have pressure that is unacceptably low but you won't know until it's too late.

If you ever wonder about the pressure, you can pull the sending unit out of the block and hook up a real pressure gauge to see what it really is. Then hook the sending unit back up and have some peace of mind.

 

Sounds like a rod bearing to me ....Lew

 

Hard to say listening via a speaker rather then the real deal but yea I'd tend to agree, first thought is rod knock.
At times though kinda sounds like a burnt exhaust valve, however a burnt exhaust valve or a rod knocking wouldn't/shouldn't tend to cause it to stall as you state it will do if left to idle on its own to long.

Might also be a burnt piston, now that would tend to cause it to stall out as the rpm's drop down low, to low to make up for the blow by condition it'd cause.

Hook up a vac gauge to it yet? see what it has to say about it?

 

Does sound like a rod bearing, But I did have a oldsmobile once that the harmonic ballencer came apart on and it sounded about like that.Just a thought.

 

A good way to sorta simplify things...IF you can keep it running long enough, use a spark plug boot puller and remove each plug wire from the spark plug. You may be able to isolate the banging noise to a certain cylinder. Use caution in doing so.

Several points to help with the diagnosis:
1. Do this after verifying oil level
2. Best time to do it is when the engine is cool, (prevents from burning fingers, hands, and arms.)
3. Steer clear of the fan and no loose clothing.
(I use a thick denim shirt and leather gloves to prevent burning if the engine is up to operating temp.)
4. Be careful.

I mentioned using a spark plug wire puller only since I don't a noid light or whatever it's called to short the plug out. IF you are going to remove the plug wires, now would be a good time to be sure that you can gain access to them without damaging anything that may be in the way. If you can get some Dielectric grease, lightly put some coating on the tip of them to help with the removal of the plug wire.

Another good tip, if you drain the oil, you may be able to determine if you have a spun main or rod bearing since it may have thrown material into the sump of the pan and it will be collected near the drain plug. Always worth the time and effort to look.
My '92, 5.0 has a clunking sound, but I've determined it to be piston slap, wrist pins or to much crank end play.

Let us know what you come up with.

 

Thanks for all of the great info guys! I'll try and get in there next weekend and see what I can find.