My 97 4.6 has always had a few seconds of slapping on startup on a cold day. But recently it has been doing it constantly. It has 91000 miles and the oil has been changed every 3000. Does anyone know of a oil addative that can help quiet it down. Would stp or luccas help something like this. I can't afford an overhaul. Any help would be great.

Budman

 

Sounds like you are talking about my 98' 4.6. It does the same thing and has almost the same miles. Does yours blow out a little blue smoke on a cold start? I have also noticed that mine does it more when its cold outside. I have cleaned my MAF, no change. I have switched to synthetic oil, a little less start up rattle. My best guess is that the cylinders have fuel in them on start up and the detonation is the sound we hear. So with that thought you would think that injectors are leaking, but I have not found any signs of that. I'm not sure whats up.

 

Anyone else have any ideas on how to quiet this noise. One thread said to use marvels mistery oil in the crank case and gas. I may try that.

Thanks

Budman

 

My 02 has started doing the same thing. It has 106k on it. Blue smoke and a rattling noise from the engine. I also only notice this on cold mornings. I may try a thicker oil in mine and see if that changes anything.

 

My 97 5.4L has had piston slap since about 30K. It now has 220K on it and still has the slap. Doesn't smoke or burn oil. It is just a little noisy at startup on colder days. Runs great, I wouldn't worry about it right now.....

 

The engine doesn't use any oil. At 3000 miles past the oil change it is still exactly at the same spot on the dip stick. It runs great but the noise is now constant. I thought that thicker oil may help but I think marvels is suposed to thin the oil. Maybe I will try the marvel first and if it doesn't work then the Lucas.
Any other ideas?

Budman

 

are you guys sure it is piston slap and not the timing chain guides?
I have heard these make the same noise and are expensive as hell to replace.

 

Piston slap only occurs until the piston skirts expand from heat to fill the cylinder. Once the expansion occurs (and it always will expand because it is due to heat) the slap stops. If you are hearing the noise even after the truck warms up, it is not piston slap.

 

I wonder what it could be then. It is a knocking sound coming from the side of the block on the drivers side. I think if it were a rod bearing it would be coming out lower and sound the same on both sides of the truck.
Anyone have any ideas what it could be?

Budman

 

IMHO - You shouldn't screw around with the oil weight and additives. Each model is designed for a specific weight oil, it tells you on the sticker under the hood. The lash adjusters are designed for the prescribed oil weight, and as they can be noisy any way, you may be making the problem worse.

 

I thought that i had a valve problem for a while now, been to the shop for tune ups, started having trouble last week and the trbl light came on, had 3 misfires going, shop changed the wire set and it idled fine but at hwy spd it back fired, hasitated, and mis fires again, i changed the coil packs my self that helped a little, so i figured i would check the spark plugs (this same shop did a tune up just last summer, WELL SUPRISE 3 spark plugs came out by hand and there were 3 dif. types and there is no way these plugs were only 8 months old, the moral is that after i was done, the valve noise's went away - so check your spark plugs you may have some blow by around the threads

 

Ttt

 

could be a wrist pin.. that is causing the nock. the 5.4's generaly have timing chain rattle the 4.6 can but ive never heard and complaints about timing chains rattlin. but the early 4.6 romeo's had bad problems with piston slap. which could be related to fuel timing or fuel quality. or u could need to get the injectors flushed. and do a ignition service and change a fuel filter. have u tried any of this to resolve the problem?

 

I havent tried those things things yet. Thanks for the info. I was going to get the injectors cleaned because it was idiling rough yesterday. It usually runs very smooth. Maybe a complete tune up would help.
Thanks

Budman

 

also clean out the EGR ports. in which u need to remove the plenum to do so