Hello all... had something bugging me for the last few months now, and it's starting to really freak me out. It hasn't gotten any worse, but the fact that it keeps coming back is starting to really REALLY bother me.

I get a slight "rattle" on only WARM starts. Never cold. I use 5W30 Castol GTX and tried both the Motorcraft and the Fram TG2 filters, same thing. Same oil pressure from both when cold or warm, no differences whatsoever in any way between the two filters, so don't even go there.

It's not a rod or main knock. Too "light" sounding. It sounds more like a piston pin, piston slap, something like that.

Never had it in all 8 years I've owned it, it only started a few months ago, is not getting any WORSE.

It happens randomly. Start it up cold, no problems, nothing, ever. Once in a while, shut it down, go into the store, come out after 5 minutes or so, start it up, and "rattle". Sounds like only one cylinder, or it could be every rotation of the crankshaft. It doesn't seem to "slowly" go away like oil pressure building. Just a "rap-rap-rap-rap-rap" like 5 times in a row and GONE.

Oil pressure when cold is up around 75 lbs or so, at VERY HOT IDLE when ambient is 90-100 degrees like it's been the past few days, I get 25 lbs. 25 lbs when it's 100 degrees outside, 25 pounds when the engine is warm and the ambient is below 50. So to me, doesn't seem like bearings.

I have a few initial thoughts:

1) Fuel injector leaking gas into the cylinder, and causing slight hydrolock. Put two cans of STP fuel injector cleaner (only thing I could find that wasn't Lucas or some other no-name brand) good for "half tank" up to 21 gallons, so a full tank at 24, it was within the bounds of the directions. We'll see if that helps, and if not, well, nothing ventured, nothing gained. I haven't heard it since but that doesn't mean anything, it's only been a few days, and I have yet to really test the "warm start" scenario yet.

2) Piston slap. But why now, and why all of a sudden, and not getting any worse, or any better, and again, just disappears like someone turned a switch.

3) Crankshaft end-play. I WILL be hooking up the dial indicator to check the end-play, probably at the flywheel end of the crank, since there's not enough room up front, and the bellhousing cover bolts would be a great place to bolt down the dial indicator. While under there, I will be checking the TC bolts, and visually inspecting the flywheel/crank-flange area to check for the known cracks that happen on the flex plates of certain vehicles, even though it only happens to '99 RVs or something around that type period. Who knows.

4) Lash adjuster, or follower.

The bitch of it is, I can't reproduce it on demand. That's going to be the hard part.

History of the vehicle:

Manufactured in October of 2000, and arriving at the dealer on 28-Oct-2000, it sat on the dealer's lot with 10 miles on the odometer when I first test drove it near the end of May of 2002. Yes, it sat on the dealers's lot for a year and 7 months and got only 10 miles on it total. It got more mileage on it between the day I signed the paperwork and when I picked it up (25 when I picked it up) than it did the entire year and a half it sat at the dealership. Between dealer prep, and it had a scratch on the rear passenger door so they had to send it to a body shop, added 15 miles to it. Weird. Also, passenger-side door handle and mirror is/was more faded than the driver's side, and the way it was parked in the lot it was obvious that that side of the truck got more sun. So it REALLY SAT. That's what worries me.

 

Oh, and one last ugly thought: Loose spark plug. But it doesn't sound like that, so that's the least of my concerns.

 

First thought to pop into mind: Warm oil is a lot thinner than cold oil. Thin oil doesn't "seal" as well at low pressure as hot oil.

Maybe as simple as a lifter with just a scoshce of clearance? Enough that cold oil seals it enough to pump up immediately, but hot oil takes a few more psi/engine rotations to fully pump up the lifter?

Also, cold oil is thicker and provides more of a "cushion" that dampens the sound of lifter tapping. Hot oil is a very thin film so there is almost no cushion.

A quick test: Try using Napa Synthetic 5W30 and see if any change. Or any synthetic, I just like Napa because it is a very good oil (Valvoline) that can be had at a great price when on sale.
The viscosity of a quality synthetic will not vary nearly as much as GTX, so if it is a lifter, the behavior will change.

If it is a lifter, I would ignore it until it gets a lot worse.

 

Good point about the oil - too bad I just changed it. I still might go with that and see what happens.

 

This is interesting. I'm beginning to wonder if maybe synthetic oil lubricates very well, but seals poorly. I KNOW you used synthetic. Maybe drain out a quart or two, and add dino?

 

I have NEVER used synth in my V10. Always used 5W30 Castrol GTX dino oil. In the V10, and my wife's Cougar, and my '96 t-bird 4.6L.

ONCE - I used 5W20 Castrol like the owner's manual (and oil filler cap says to). And I heard the timing chain whirring like the double-roller on my 390 FE in my highboy. Same noise I heard when I bought it BRAND NEW from the dealer's lot, which I assume was 5W20. Went back to 5W30, no more chain noise.

That chain noise was noticeable to ME. Probably not to anyone else. After working on Triumph TR7's for decades with OHC and a chain that's exactly like Ford's. But I did hear it, it bugged me, and going back to 5W30 just like the 2000 owner's manual said, and I never had a problem.

Gee, I wonder if it's a timing chain guide?

I'm going to spend some time in the next week or so figuring out if I can duplicate the noise.

 

Well, bummer, I would have thought your injector cleaner might have helped. There's no stronger proponent of the V10 on these forums, hope you don't get screwed.....

 

It's definitely not an "oh ****!" sort of noise. To be honest, it sounds tinny/aluminum, more like a heat shield would, but it's definitely in time with the crankshaft/cam rotation. So I'm leaning towards a piston slap or mild hydrolock from leaky injector.

If it were a lifter/lash-adjuster bleeding down, I think it would do it on first cold startup once in a while too.

The injector cleaner has not had a chance to do anything yet, it's only got about 5 miles on it since I put that stuff in there.

I still have the last oil filter I took off of it, I think I'll open it up and investigate. Not sure I really want to

I just got a complaint from the Incorporated Village of Lindenhurst about "parking on the grass" - probably when I did my 2-day Father's Day weekend muffler upgrade and pissed the neighbors off with all the grinding/cutting noise Either that, or the Village likes to harass a family diagonally across from me about parking their leakers in the street for months at a time and they think I called in a complaint on THEM. Little do they know, I never call on them, the village drives by and sees the cars with no inspections/registrations (god knows how they have plates for them) and tickets them out the wazoo. Over $2K in parking tickets in the past 5 years. Idiots, and they keep doing it.

F 'em. I'm gonna keep working on vehicles back there until the village comes down to me and says "move that thing" at which time I will say "Got any pictures? Because without it, you have no proof I did it". There's a "garage" behind the house - it's an obvious garage, been there since the 50's at least. Too bad the house is a prefab installed after the original burned down, and it's too close to the front of it, otherwise I'd "park" the truck inside of it (barn doors, the garage is pretty big). Ah well, the fun of living on Long Island. Maybe I should get the original tax maps and see if there was any driveway or other access to that garage.

 

Have you checked your fuel pressure with the engine off in the AM, before the first start? If you have a leaking injector it might help to narrow it down. I'd check that first and then check it again right after shutting the engine down and then again about a half hour later just to see the variation and possibly eliminate the injector as a potential problem.

I refuse to live in a neighborhood with a HOA. Been there and done that. Didn't like it at all.

 

Mel, good point. Makes me want to install a permanent fuel pressure gauge. I have one too, meant for constant use. Not that I'm going to run line into the cab, it'll be under the hood. Food for thought.

This is just an incorporated Village, with a population of around 1500-2000 people, in a larger town with the same name. I could move a few blocks over and be out of the Village. If I wasn't already paying the lowest rent possible for the past 15 years, I'd move in a heartbeat

 

That sounds like an over zealous town council and maybe you should run for a seat and straighten them out. Every town council needs a motorhead on it.

 

Yeah, me run for public office. Talk about the lunies running the insane asylum. On the other hand, it might actually help

 

Give it a shot. What have you got to lose? Except maybe your sanity.

 

I lost that somewhere back in the 80's.

 

2002 V10 started last week. I have a motorcycle with an auto adjusting timing belt and sometimes when I crank it, it sounds like a valve rattle a few second then it goes away.

Sounds like the same thing in this truck

145k miles and I used Mobil1 5w20 from about 12k miles until current. Never really towed anything besides a small boat 15 times.

Someone told me to change the serpentine belt pulley. Dunno

I have never changed a thing in the motor. I actually ordered plugs, boots, pulley, belt, hoses, radiator fluid etc 2 weeks ago to change now. Weird it happened at the same time.

I do all my own work, but the stuff you mention about crankshaft gages and fuel pressure gages I have never done and have no tools for.

Just saw this thread so I am gonna keep searching and see if I find more. Please let me know what you found.