1993 4.6 whirring noise
 

from the passenger side head I think. I lubed the pulleys to make sure it wasn't a pully going bad on that side (idler and tensioner). I'm afraid it might be a cam bearing giving up on me. Has anyone dealt with this issue and have an idea of how expensive/difficult it is to replace a cam bearing near the front of the engine? If it was anything outside of the engine I'd probably figure out a way to fix it, but internal stuff is usually beyond my ability and tools.

It doesn't make the sound when the engine first fires up. but after a minute, tops, it starts this muffled whirring noise. I have half a mind to take the belt off and run it for a few minutes just to rule out accessories for sure, but probably won't be able to do that until Saturday.

Any ideas are definitely welcome as I'm not in favor of having to spend a lot of money at the moment.

There aren't really any cam bearings.. The perches on the head are machined for the cam journels to ride in.. Never heard of any problems in that area short of running it without oil... I would think if were something cam related it would be a tapping or clunking

I'd start with throwing the accessory belt off and see if that quiets things up.. Spin all the idlers, and accessories by hand to see if you can feel anything like a rough bearing.. Idler's going bad are more common...

The other thing I've run into from time to time on 4.6 cars is the starter dragging.. The starter drive doesn't completely disengauge from the flywheel.. From outside the car it sounds more like a grinding noise though.. Usually this noise is there as soon as the car starts, then goes away after a min or so...

Simular Issue
 

2004 Grand Marquis GS (78k miles)

At first I thought the clanking and clicking noise was coming from the front of the engine. I replaced the tensioner and idler pulley with no success.

The noise sometimes happens during acceleration (not consistent). Usually after the car has warmed up. I had a neighbor listen while the car was in park. By pressing a little on the accelerator pedal we were able to hear a grinding noise. We concluded the noise was coming from behind the engine.

I remove the rubber cap next to the flywheel casing and wasn't able to find anything loose inside. I even used a magnet to see if I can grab anything that might be rubbing against the flywheel. No luck.

I research the web and found the clanking noise maybe coming from the catalytic converter. I visually inspected the converter and only found the heat shield to be a little loose. The noise maybe from something loose inside the converter.

I ruled out the starter (not retracting) because it only happens during accerlation?

Out of desperation I put a bottle of STP oil treatment and seemed to muffle the noise for a short while.

Rod bearing? I used 10w-30w Mobil 1 extended performance for the life of the car. Changed oil every 5k miles. Normal driving.

Any ideas?

sorry i cant be more assistance. my knowledge is more in the 5.0L pushrod engines and not the 4.6L modular engines. if it were me, i would take the car to a shop and act stupid to have it pinpointed.

Generally the 4.6 from 93 on is pretty darn comparable to a timex.. Exluding those darn plastic intakes from 96 up.. Quite a few of them in the 250,000 mile + club... One of the few engines Ford has built, other than the 460, with decent bottom end oiling.. I've head of a few cases of "piston slap" where the skirts of the pistons wear causing them to rattle around in the cylinder bores.. This usually quiets up once the engine is warm... Some of the higher milage engines will get some timing chain slap that once again goes away with a min or two of running.. The fact that the stp made it quieter is troubling...

joeguzman10,

Two questions

Does engine temperature make a difference? For instance is it louder with the engine hot?

And, If you have the car in park and rev the engine with no load does it still make the noise? Or rev the engine to about 2500rpm (roughly if yo have no tach) then vary the engine speed by a few hundred rpm up and down can it be heard?

Does having the a/c on or off may any difference??

Okay sorry that was 3 questions...

@SLYxxx: Are you sure it's not the common noise refereed to as "moaning"?

Greetings!

92Merc: moaning? (I assume not the steering pump moan like in my 88 MGM when the tank is low)

'splain?

just did the belt-less check... it's the idler pulley. the bearings feel like gravel in that one. That's an easy fix. off to get the part now. ;)

Good deal..... Idler bearings turning to gravel seem to be somewhat common..


I believe the moan he is referring to is one caused by the Idle Air Control Valve... Most of the time it can be fixed by cleaning the valve... I guess this was much more noticeable on the '96 and up with the plastic intake... Alot of the time hard starting/stalling/funky idle go with this..

If mind serves me right there was was a short time where Ford had an updated IAC for the '96 & '97 cars to cure stalling issues.. Turns out most of the stalling issue was a buggy canister purge solenoid...

fun. now if I could figure out why my 88 mgm doesn't like to start right away when warm like it does when it's cold. I'll check the IAC on it and see if it needs cleaning.