2003 Ford Explorer - 4.6L Timing Chain Issues?

[protraxrptr17]

Car came in with a noise under acceleration. Sounds almost like a heat shield.

I checked all that and found nothing. Pulled oil pan and found a piece of plastic. I knew then it was a piece of the timing chain guide. found passenger bank chain loose. Replaced guides and tensioners. Still have the same noise. Pulled valve covers and I can take my finger and push on the chain and make it get slack.

The tensioner wont tighten it back up. Do I have a bad tensioner? How do these work? I'm guessing oil pressure.

[Tim Martin]

I have run into this already. And, yes, the tensioner is fed by oil pressure. Specs are 20-45 psi at 1500 rpm. Oil must be 5/20 Synthetic. This engine does have oil pressure issues and you could wind up replacing the oil pump as well.

[steven kiser]

oil pressure is the answer.

[protraxrptr17]

I just finished putting in a new oil pump, no change. I found no metal in the oil pan or filter. I did notice that the passenger side tensioner felt like it had oil inside. I had to push real hard on it to get it to release. Driver side felt springy. Just the same as it did when i took it out of the box. I also put compressed air into the ports behind the tensioners. There is a open hole in both heads at the end. SHould it have a plug? I dont know what to do. I even put smoke into the ports. I got equal amounts of smoke out of each lifter. Saw no real difference between each head. I put the "L" tensioner on the drivers side, and the "R" on the passenger side. Only difference I seen was a small hole in the end of the "R" plunger. Oil pressure is good. This car has been here too long. Shopkey gives a vague explanation about a "serviceable" orifice for each head, but does not give a location.

[Tim Martin]

Have you checked actual oil pressure with a live mechanical gauge? At the risk of sounding like I am insulting your intelligence, the oil pressure switch is on the left side of the block, behind the power steering pump as I recall. Thread that out and install a live gauge on a hose (mine is 6 foot long) and watch oil pressure through different engine rpm's. Also, what weight oil is being used?

[protraxrptr17]

oil pressure is about the same on both heads, maybe a couple pounds more on the driver side. I checked it at a 1/8 npt plug at the front on the pass rear on driver. Just got done doing that.

[protraxrptr17]

I checked it with a 100 psi pressure transducer on my modis. I'm using 5w 20. This engine looks nice inside too. I checked the pressure at varying rpms. especially close while the noise was going on. Right now I have no belt or anything on the engine to interfere.

[Tim Martin]

A previous job is reminding me that these engines also have lifter issues as well. What I am saying is don't rule out the possibility that the noise is lifter related.

Just a thought.

[protraxrptr17]

How can I check those? Pull em out and squeeze em? What should I do next?

[Tim Martin]

Well, I have not physically removed lifters strictly for checking them. What I do is use my electronic stethoscope and determine precisly where the noise is coming from. If the loudest noise is coming from the front of the motor then the problem likely is a chain issue of some proportion. If the noise is coming from under the rocker covers, then the lifters are the most likely suspect. I simply replace all of them not taking the time to check each one individually. Oh diagnosis takes time, I know but with the cost and complexity of today's drivetrains, ya gotta know with precision what's going on and where the fault is.

[steven kiser]

just a passing thought here. a cracked flywheel will make such a noise that can and will travel through the crank and sound like it's coming from the front of the engine.

[Tim Martin]

just a passing thought here. a cracked flywheel will make such a noise that can and will travel through the crank and sound like it's coming from the front of the engine.

Oh yes. Hadn't thought of that. I have also seen that.

[protraxrptr17]

Already had the transmission out and looked at that too. I'm gonna go to the salvage yard and get some valve covers and cut out the front where I can watch and listen to the chains to make sure that is the problem. It's really hard to tell where the noise is coming from. I do not have an electronic stethoscope. ALways wondered if they really worked.

[Tim Martin]

. ALways wondered if they really worked.

I would not be without mine now that I have had it several years already. My hearing is only 40% and in a situation where noise is coming from - the electronic stethescope is the tool of choice.

[protraxrptr17]

just tracked down my snap on guy and got the blue point. Just a quick check at idle i can hear a definite louder noise on the pass side part of the cover. Waitin on my worker to finish something so he can put the engine under a load. This stethoscope really does work.

[jbadenoch]

i didnt even know they have an electronic one, have a regular stethascope, seems to work well in identifying noises

[Tim Martin]

I was a bit skeptical before I got mine but now that I have it .......... my other one collects the floating dust here in the shop. With mine I can hear current jumping inside a cracked spark plug. It is definitely one of the best tool purchases I have ever made.

[a&mauto]

oil pressure is about the same on both heads, maybe a couple pounds more on the driver side. I checked it at a 1/8 npt plug at the front on the pass rear on driver. Just got done doing that.

What pressures did you read at idle & 2000 rpms?

[protraxrptr17]

about 70 at idle 80 at 2000 rpm. thats engine cold.

[Tim Martin]

Well, based on those oil pressure figures, I'd be forced to conclude the problem is elsewhere. If there is definite noise under a particular section of rocker cover, I'd likely pursue that. keep in mind that in these bi-metallic engines, noise can travel and fool the tech. Been there done that. And those hollow camshafts on the 4.6L and the 5.4L engines - noise really resonates through them.