First, I have searched the forums for an answer. I didn't see exactly the possible problem that I am having.

When I first start the truck, no matter the outside temp., I get a light tapping noise from the engine compartment. I have tried to isolate the noise to a component and can't seem to. This started about two months ago after my last oilchange at the dealership. The noise does go away after it reaches normal op. temp. I really don't know what has or has not been replaced on the truck. I bought it used this year with 41,000 on it. I have 52,000 on it now. I do mostly highway driving and have driven it from Arizona to Indiana and back also Arizona to California and back. I drive about 90 miles a day round trip to work. Here's the truck info....

1999 F-150 Supercab shortbed 5.4/Auto 4X4.

Thanks in advance for your comments and suggestions!

 

try some lucas oil additive. i understand what your saying though. with 52000 miles on it it shouldnt be doing that. try changing the oil yourself with the right grade and see what happens. do the filter to.

 

I have a 97 F150 4X4 Supercab with the 4.6L that does the exact same thing. There is light tapping sound when the engine is cold but once it warms up it sounds like it should. It has 130,000 miles on it and runs great. It has been doing this for a while now. I bought the truck used so I don't know about the previous owner but I change the oil and the filter every 3000 miles. It has been puzzeling me also so if anyone has any advise or has had a similar experience please let us know.

 

Ok, Ok, I guess I didn't look in ALL of the forums. I can admit my mistakes. If someone hasn't seen it yet, the forum for the 5.4 has an extensive thread under "5.4 cold engine knock." Lots of good info, maybe too much whining!

 

Is it an exhaust leak? Maybe a broken manifold stud or two?

 

my '98 4.2 has 117k on it and does the exact same thing. i do 99% of my driving on the highway and change the oil and filter every 5k miles. and use motorcraft oil w/ NAPA gold filters.

 

I listened and looked for an exhaust leak this a.m. That's not it, at least as far as I can tell. The thread under "Performance, engines, and troubleshooting" "4.6L, 5.4L Modular V-8" is two pages long at this point. One of the users, fordmoparman, wrote that he is a Ford Master Tech and has this to say...

Posted by fordmoparman on 05-13-2002 10:26 PM:
5.4 Cold Engine Knock
"ok ill expose myself here anyway im a master ford tech to all you guys that have piston slap and it is piston slap i have tore down these motors myself and you cannot find anything wrong with them but what is happening is major engine design change compare a 351w piston and a 5.4 or 4.6 piston and youll see why they are having problem 4.6 and 5.4 are very short skirts and when you do that you run the risk of slap these motors will run for along long time i know some of you dont like this but consider the guy that said his truck wont be the same i feel hes right in some ways unless you have a trusted tech there are some hacks out there that dont care about your truck all they see is how fast can i do it! so i think unless your truck is really really bad 2 minutes or more i would leave it alone but hey thats me!"

I am going to change my oil today and try the following...

Posted by wmcnally on 10-04-2002 02:09 PM:
5.4 Cold Engine Knock
"I have a '98 with a 4.6l. Bought it with 6,000+ miles on it. On cold start up it had piston "noise" that lasted 10 to 15 seconds.

I changed the oil to Mobil 1 (5W-30)and used the recomended Motorcraft oil filter with the anti drainback valve. The "noise" was gone immediatly
and 10,000 miles later never heard again.:-)"

It seems that Ford is aware of the problem but claims it is normal. Several of the FTE users have had the engines replaced and some say even the replacement engines do the same thing.

I'll let you know how the oil change works out for me.

 

I am also going to try the Lucas Oil Additive as well!

 

1968stepside,
you are the 3rd person this week i've heard(or read) that mentioned some type of Lucas additive. is this the new Slick 50 or is this stuff for real? and do you need to add w/ every change? does Lucas make an additive for diff? a friend was just saying this morning that he was going to add Lucas trans additive to keep his Mopar minivan from going thru another auto gearbox.

 

BTW, we aren't talking about the same Lucas that built the electrical systems for way too many English autos, are we?

 

it could be just carbon build up on the cylinders. i have a 2000 w5.4 84,000 on it and no issues. but a friend has a 2001 gmc w/6.0L w/20000 on it and it does it. what multiple people said was just carbon build up on these new engines. just a thought it doesnt hurt just sounds like crap. same principle it goes away after the engine warms up.

 

mars, I am not sure about the electrical stuff. The bottle of Lucas Oil Treatment I used today has instructions for useing it in the engine, tranfer case, and differentials. There are different ratios for each component. I do remember seeing other Lucas products on the shelf. I think there was one for trannys too. I am not sure if it is a must on every oil change. I will research that this week and let you know.

I did the oil change with 5w30 Valveline Maxlife and the 32 ounce bottle of Lucas with the Motorcraft oil filter. I had briefly started the truck early this morning and it was tapping as usual. I drove one of my other vehicles to get the oil and stuff. I moved my truck to a level surface, still tapping. I did not let it warm up. After the oil change and the Lucas additive, NO TAPPING!!! We will see tomorrow a.m. when it's 40 degrees and has been sitting more than 8 hours. So far, so good!

If you look at the other thread that I have mentioned there are several people ready to throw Ford away. That's not me. If there is a perfect vehicle out there without any problems or "character" I'd like to know about it. If it does exist, I am sure I would never be able to afford it. Maybe all of the whiners should walk everywhere for a week or so and see how they feel!

 

This a.m. the tapping was completely gone. The truck had been sitting for about 12 hours and it was 48 degrees. Not one knock, rattle, or tap.

If you want more info on the Lucas stuff check out...

www.lucasoil.com

 

Thanks for the info 1968stepside. I know what I'm going to do this weekend. I'll let you know if the knocking in my 4.6 goes away after changing the oil and trying some Lucas additive. I'll make sure the new filter has the anti drainback valve also. I always assumed that the filters I used had this feature but I have never actually asked. I usually use the NAPA gold. I usually use 10w30 but I try the 5w30 this time.

 

Glad I could help. I hope it works as well in your engine as it did mine. I have had mixed responses from mechanics I know about useing synthetic oils. The one common answer I get is if you use syn oil, use Mobil 1. I have also been told by some that the engine needs to be flushed so the oil and the syn oil don't mix. I wasn't ready to do that myself yet or spend $30.00 in oil only each oil change, especially since I end up changing my oil every 7-8 weeks. I'm sure it is good preventative maintenace, just have to convince my better half that it is worth it. Good luck!