Hello, all. I have a question. I have a '99 Expy XLT 4.6L with 64,000 miles on it. Lately I am having a knocking noise when I start the truck up. It is pretty loud but it only does it for about 10 seconds.

At first I was terrified and thought it was a rod knock. But it isn't. I checked my oil level and it was fine and my oil is changed religiously at 3000 miles anyways.

Then I thought it might be the harmonic knocking against the timing cover. I blew a harmonic on my old '94GT because of the blower on it and it made allmost the same noise as I am hearing now from the truck.

And here's the other weird thing about this...it only happens when it is really cold outside. If it is in the 50's or higher it doesn't do it. Nor does it happen when I start it up numerous timed (like out running errands and going from place to place).

It only happens after it sits for a long time (overnight or after work) and when it is really cold out.

Also...It does not do it when I get the RPMs above 2000 when idling nor does it do it under load when I am driving

Any suggestions that y'all might have as to what this could be?

Thanks.

 

Sounds like piston-slap due to high tolerances within the engine. Will not hurt anything and Ford says it's normal. Make sure you use a Motocraft FL820S oil filter when doing oil changes.

 

What weight oil are you using?

 

98Navi,

I am using 5w-30.

Yankee,

Thanks. Exactly what tolerances are causing this? Did Ford ever put out a TSB on it? First time I've ever heard of something like that.

 

What brand of filter are you using?

 

The Motorcraft one that you listed in your post. I had to go check the part # on it and it is the same.

 

That was Yankees post, but thats a good filter. This is a problem on some fords, more when you change the oil from what I hear than daily. It could also be a combination of the cold weather. Do you park outside or in a garage?

 

I park outside. I think it is the weather that really affects it. But today it didn't do it even though it was 29 degrees when I left work this morning. I've looked at just about everything I can think of so it's got to be that piston slap. I saw another post on another Ford forum where numerous Expy drivers have reported the same problem with only one suffering bad problems. One guy has 125K and no problems at all.

 

Mine does that too, when it's really cold out. Doesn't seem to bother it, i's got 80K miles on it, 20k of which are mine. I only use Ford's express lube, so it always gets the proper Ford filters.