engine knock

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Mar 20, 2011 | 06:02 PM

lee1964

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engine knock

I have a 1990 ford e-250 van with a 4.9 straight six and it has a slight engine knock any ideas what to look for.

Mar 20, 2011 | 06:39 PM

DBGrif91

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From: Des Moines

I don't know if the 4.9's have a knock sensor, but if so, that could be it. They can produce a knocking when they go bad. Here's a page for more info on that. Ford Fuel Injection » Knock Sensor (KS)

If that's not it, it's not difficult to narrow it down. Take a long screwdriver and probe the engine while it's running by placing the tip against the motor and the handle against your ear. This is essentially a poor man's engine stethoscope. So, for example, place the tip against the valve cover and the handle against your ear. If that's the source of the knock it will be more prominent with the screwdriver to your ear. You should be able to probe most of the motor with this method and that will help narrow it down. Once you've isolated the area it's coming from you can start looking for possibilities.

Mar 20, 2011 | 06:40 PM

drjoe171

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Joined: Sep 2010

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From: Oregon

is it like a little tapping hammer at idle.
The ultimate is to determine the time of the tap interval, either crank or valve related.

EZ to check your oil pressure,
Read about fram oil filter failures and make sure you don't have one on there,

Or does it rattle when you accelerate?

Mar 20, 2011 | 07:00 PM

IDIDieselJohn

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From: Ottawa, Ontario

300 Straight 6 eh, must be something in the valvetrain as it's *pretty* rare you see a straight 6 knocking from the bottom end.

Mar 20, 2011 | 09:46 PM

DBGrif91

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From: Des Moines

Quote:

Originally Posted by IDIDieselJohn

300 Straight 6 eh, must be something in the valvetrain as it's *pretty* rare you see a straight 6 knocking from the button end.

I don't know John.... those buttons aren't so obvious sometimes!

Mar 20, 2011 | 09:49 PM

IDIDieselJohn

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From: Ottawa, Ontario

Me and my silly typos sometimes.

Mar 20, 2011 | 09:52 PM

DBGrif91

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From: Des Moines

No biggie- we all have slip ups. All I know is it's a good thing my wife has no interest in reading these boards- her head may explode from all the grammatical and spelling errors!