A very funny sound started to come from under the hood of my '99 Explorer 4.0 EFI with 131,00km.
It sounds like a bad or very dry bearing, it gives off a squealing sound and other times a chirp. This is intermittent and very hard to detect where it's coming from.
I thought at first it was the belt tensioner, so we changed that. No difference. We then changed the idler pulley. Still no change. It is not coming from the alternator, that is running quiet. We also changed the belt, still no change.
Possibly the water pump?
Sometimes the sound seems like it comes from the back of the engine, the only thing back there is the distributor. Could this cause that noise? Bad bearing on the shaft? I wouldn't think so but the reason I ask about this is that the engine has been having a bit of loss in power (progressively) and it pings badly under load, almost like it's not advancing, again progressive. Possibly this may just be caused by dirty injectors?
Any help would be appreciated, this has me stumped!
Personally I would remove the belt and run the engine for a few seconds and see if it goes away--that would narrow it down to something that is driven by the belt. You could try turning stuff by hand and see if something is squeaking or hard to turn.
If it's pinging I would think you'd be getting an error code.
ive had some fords making those noises and it was the belt that needed replaceing , one case when antifreeze was spilled on it..dont get any dirty hands on it when installing.
I'm hoping we may have solved the problem. I'll know more tomorrow when I run the vehicle to the city and back.
The new replacement belt tensioner was the wrong one, it rubbed on the belt when installed so we had to remove it and put back the old tensioner but used the new pulley from the new replacement as the old pulley ran rough. Even after a new belt was put on, the chirp/squeal was still there but only when revving the engine. This indicated that perhaps the belt was slipping.
I looked down to the old tensioner and saw that instead of running smoothly, it was bouncing a bit. This indicated to me that perhaps the spring was weak. I went out today and picked up another tensioner from a wrecking yard, checked for good bearing and tension, it was good. Put this on, fired up the engine and it gave a couple of quick chirps, then ran quiet. The pulley from this wrecking yard tensioner had a wee bit of oil and crap on it.
I ran it around town for a test run, doing quick accelerations to see if the noise came back but it ran quiet right through the test.
Hopefully this was the issue and problem solved but will know more tomorrow on the longer trip.
Next week, I am taking the vehicle into the ford dealer to run a test for any codes to see if all checks out OK. The ping and loss of power may be nothing more than dirty injectors. I've fueled it from close to empty and added injector cleaner to see if things come back to normal. Probably be a good three tanks of fuel before any noticeable difference though if code reading comes up empty.
What brand of belt did you put on there? I think every case I've read about (except yours where the tensioner actually had sign of problems) where the tensioner was suspect it turned out that the after-market belt was just a bit too long.
Just in case you don't know many auto parts stores will check the codes for free. I suspect that Ford will charge you $80 or something like that plus they will find $6000 of repairs that you need.
The ping and loss of power
It sounds like you are the kind of guy that woulnd't have a dirty air filter but have you checked the MAF and the IAC? My daughter's '97 (4.0L OHV) had the CEL on but I don't think she mentioned any pinging and I blew out the air filter (we drive on dirt roads a lot so we don't change the filter every time it gets dirty), cleaned the IAC and MAF and throttle body and after driving it a few times the CEL went off and stayed off.
I have a '92 Exploder and at about 240,000 miles it was pinging and I had to replace the timing chain but this is very rare on the OHV engine. It was off by two teeth. It sounds like you have the same engine and NOT the SOHC which has a lot of problems with timing chain tensioners. If the 8th digit on you VIN is X then it's the OHV. Another thing that can cause a pinging sound is a bad starter motor--the gear won't retract and you will hear it hitting the flywheel but usually only while going uphill.
Air filter is clean, IAC was just replaced due to bad idle. Haven't done anything about the MAF, don't even know what that is or where it is.
No check engine light, all lights are off on the dash when running. Everything runs normal except for power loss, ping and this dang screeching sound. My pinging is more like a rattle like lifters are loose or something but only hear this when under load like hill climbing, accelerating, etc. My dad's old straight six pickup on the farm did this.
My VIN is X for the 8th digit so then that would be the 4.0L OHV.
One other odd thing is when it's cold, out side temperature being 10 degrees C or lower, oil gauge sits on the bottom, CEL is one, then oil gauge needle jumps to normal after engine has warmed up.
Back to the chirping, I thought it was belt related, tensioner, idler, bad belt, possibly bad bearing in the alternator. New tensioner was put on, new belt, new idler bearing, still chirps. Tonight my wife and I went to visit a friend, when we were coming back, the chirping came back, this time accompanied by a screech.
I opened the hood and listened while it was idling. The sound started almost inaudible, then built up to a screech, went quiet, then started to build up again to the screech. The sound was definitely coming from the top of the engine, about halfway to the back or maybe all the way to the back of the engine, was NOT from the front at all. I was almost certain this was where the sound was coming from the other day before belt change and tensioner was changed.
Could this be a time chain issue?
I drive on alot of gravel out where I live, pavement too. Suspension is starting to sound like squeaky bedsprings.
Since this all started, I haven't driven it much at all, don't want to damage anything.
Looks like it's back to driving the gas hog pickup until I get this sorted out.
I had a '92 with the OHV engine and had pinging problems all the time. There were a lot of posts in this group about the cause being leaking intake manifold gaskets, but don't know if that applies to the '99. I had a '99 but it was the SOHC engine and I did not have pinging problems with that. I finally started using premium gas in my '92 and that stopped the pinging, but may not be an option with the '99 as it might cause the CEL to come on.
On mine, I have a bad feeling that it is more serious, the screeching, chirping noise coming from the top of the engine towards the back has me thinking the engine will have to come apart. Sounds like a dry bearing somewhere.
My ping is lifter noise, rattles like a diesel, not when idling mind you or general running but when power is needed.
Looks like the vehicle will have to pay a visit to the Ford repair shop.
On the earlier Explorers there were lots of problems with leaking head gaskets and that could result in a loss of power under a load such as going up a hill but you would probably have other symptoms such as your coolant overflowing and it might run too hot.
Gee whiz, the only thing that comes to my mind that could cause screeching would be a slipping belt and it sounds like you ruled that out. If nobody else shows up soon with some more ideas it sounds lilke you might have to take it to Ford. As far as the timing chain goes that is extremely unlikely on your engine.
On second thought power steering pumps can make a screeching noise if they are low on fluid or maybe are just plain worn out. It's (or used to be) on the driver's side near the front so I suppose it could sound like it's in the middle.
Yea, well, at least you have a pickup in the meantime. My wife wants me to sell my old '78 F350 cause it gets such terrible gas mileage but heck, sometimes you just need a pickup. Besides that I just like it. It's not just a truck, it's an adventure.
Well, Discovery Ford has the Explorer now, they will diagnose it tomorrow. Mechanic had a peek, there is a shaft that is where what used to be called the distributor. He said other fords with the same type of engine had the same problem. Doesn't sound like it's a timing belt or chain, runs too smooth for that. I'll know more when they call me with the bad news...or good, depending on how one looks at it.
It was funny, got the hood open, we were all gathered around it at the service entrance, not a peep out of the dang thing. Then suddenly...screech, chirp, chirp. They all heard it!
My pickup is '84 GMC Sierra, 350 engine, goes like stink. My wife would rather me not have that either but....today, she's glad it's here;-) At
110km/hr in OD, tac reads 1900 rpm. Explorer does 2200rpm.
I have a !996 4L (not OHC) that does this screeching when it is left ticking over, or, in traffic jams,(runing slightly warmer?) goes soon as you rev the engine. i have not been able to diagnose it either. No loss of power or other symptons. I tried spraying all the belt pully's with WD40 made no difference. I wonder if its the EGR valve. Very interested in any diagnoses though.
Just got my Explorer back from the Ford shop today, been in sick bay for the last week and a half. What a world of difference. Back to plenty of power, goes like stink, all weird squealing, chirping noises are gone.
Here is what was done at the Ford dealer:
A. Check chirping noise from top of engine C: Checked chirping noise from engine C: Found that noise was most evident from back of engine. The Sychronizer assy is most common and would recommend changing sychro and cam sensor together. Replaced cam sensor and sychro assy as a pair. Had to remove coil pack, trans dipstick tube, wiring harness and pry out and fight to get assy out (seized in hole)
Labor....294.50 Parts....337.91
B. Check lack of power C: Road tested vehicle. Did not seem to be too bad for power, wasn't sure if this sympton was more evident hot or cold. Checked oil level OK. Spark plugs recently replaced, air filter looks good, MAF sensor looks clean. Suggestions that could be made known to the customer would be that there is an update for the PCM, KAM could be reset, fuel filter could be changes and also there are no codes. Replaced fuel filter, reset Keep Alive Memory and updated PCM for better vehicle performance as per customer concern.
Labor....199.50 Parts.....21.07
C. Check oil pressure gauge-Doesn't come up right away and check engine light comes on as well. light goes out when gauge comes up. C: Check oil pressure gauge concern C: Found that there is an updated oil pressure switch for this concern C: Replaced oil pressure switch
Parts.....18.48
D. Check lifter noise when pulling or accelerating C: Checked for lifter noise C: Could not seem to duplicate but did find several service messages stating this concern could be from carbon buildup inside the engine. Could suggest de carbonizing engine.
So, that was it. Fix was done, good power on hills again, no gearing down on the hills like before when in cruise but muscles itself to the top of hills with no problem, just like when it was new.
Did not do the de carbonization of the engine, lifter noise is all but gone now, very slight. Again, only under heavy load like steep hills. I'm thinking that if there is any carbon buildup, it's due to alot of short cold starts and stops, I would guess.
So....do have a new belt and a replacement tensioner that wasn't needed yet.
Oh, replaced the front and rear stabilizer bar bushings too, I live in a dusty area, especially at harvest time, these were sounding like rusty bedsprings! Nice sounding bump, bump now when going over rough roads.
As previously stated My 96 Ex' does this screeching if left ticking over OK when running. Can anybody expand on this Syncro problem is it an easy DIY, what parts do I need? would freeing, lubricating, do anything.
I have a 96' Explorer which experienced a similar chirping noise. The culprit was the CMP (cam position sensor) assembly. It's in the rear of the engine where the distributor would normally be in the old days before everyone switched to computer controlled ignition systems. Here's a forum thread about it. It's a pretty common problem with ohv 4.0's...... "
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"It's not a cheap or easy fix. You must remove the intake manifold to get to it.A new CMP sensor costs about $180.
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