Timing Cover Removal

[MrEvilPirate]

My timing chain tensioners just arrived, hoping once installed they'll take care of my cold start rattle.

I have an intermediate rattle around 2500 - 3000 rpm, really slight, almost hard to hear. I'd like to replace main guides, or at least take a look at them.

My manual says engine needs to be removed to remove timing cover... need to remove oil pan???? Is this true? I think I've read info to the contrary has anyone here done it? Every motor I've ever had no issue at all popping the timing cover off. Thanks.

 

[RonD]

4.0l SOHC has rear timing chain and guides that need engine removed to change them, tensioner can be replaced with engine in vehicle.

Image here with front cover removed: http://www.explorerforum.com/forums/index.php?attachments/exp019-jpg.64389/
(you can see a short timing chain lower left, this was only on 4x4 engines, for balancer shaft to offset front drive line vobrations)

You can remove front cover without pulling the engine out, but not sure why you would want to?
Front chain tensioner was never a problem, longer rear chain and front drivers side tensioners were the ones that caused the noise and failure of the guides.
You do need to loosen oil pan to get a bit of clearance at the bottom seal, in above image you can see about 1/2" or so gap between pan and block

If you have the engine out to repair rear chain then you would pull front cover and replace all the guides and chains, along with tensioners.

Correct procedure for any timing chain cover that bolts to oil pan is to remove oil pan first, then remove front cover.
Reinstall front cover and torque to spec
Then reinstall oil pan and torque to spec

Obvious reason for this is the oil pan gasket sealing
Do you have to do it this way...........no, your vehicle, you can do it the way you want, and live with any leaks, lol.
But if you put on flexible sealer(silicone or similar) to fill any gaps you should be fine.

 

[gw33gp]

I have never taken a 4.0 SOHC timing cover off but that link shown must be for a push rod engine. The chain tensioner is in a different place and there are no timing chain going to the cam in the head.

 

[RonD]

It is there, but behind the "Cam" gear, jack shaft gear

Another image here: http://www.explorerforum.com/forums/index.php?attachments/sohcvalvetrain-jpg.39119/

4.0l OHV seen here: http://engineguy.com/media/catalog/product/cache/1/image/650x/24a8e871609ef9b97781ff3d1eff1574/a/t/atkdfz8-1_1.jpg

 

[gw33gp]

Ok, I see how it works now. I guess the tensioner is normally not replaced on the shorter main chain. I know the tensioner for the longer front cam chain is on top near the thermostat.

I looks like replacing the front cam drive sprocket requires considerably more disassembly than just removing the timing chain cover.

 

[adsm08]

I have never taken a 4.0 SOHC timing cover off but that link shown must be for a push rod engine. The chain tensioner is in a different place and there are no timing chain going to the cam in the head.

I have done both, there is very little difference between the two.

 

[MrEvilPirate]

I guess I should just replace the tensioners and see what happens. I have time to do it tomorrow. This whole thing has me sick to my stomach. I listened for rattle when I bought this truck and thought it was good to go. The noise I get is nothing like the youtube videos. MUCH quieter, I didn't even notice it until driving the truck for a couple weeks. The startup rattle is louder, but not super bad. I'm confident new tensioners will do the trick. The rattle when driving starts around 2600 RPM. Almost like resonance causing something to shake. Does the death rattle start quiet and get louder, or does the chain guide fail all of a sudden and you end up with the loud terrible rattle from the youtube videos?

My understanding is that the tensioners need replacement because the spring wears out, which is what tensions the chain at startup. Once running oil pressure keeps the tension... any chance it goes away with the new tensioners?

I'll let you all know what happens tomorrow. Thanks.

 

[MrEvilPirate]

Here is a video of my sound:

https://youtu.be/QlRVKGLGToQ


Almost like a ticking sound within the cab. Am I chasing a ghost?

 

[RonD]

yes, poor design with the tensioners used on the 1997 to 2004 4.0l SOHC engines,
most of 2005 got the newer design, all of 2006 got the newer design and any newer ones will be that design as well.

When engine is stone COLD remove fan belt so fan and accessories won't spin.

Start engine, quiet engine bay(no fan) makes listening much easier to ID any engine noises.
You can run the engine for 2 minutes with no water pump, but no longer, and it is plenty of time to isolate noises and locations.
Cam Synchronizer can make a noise as well, but usually not described as "rattle" like chain noise

If there is no more noise, then noise is coming from a fan belt pulley, i.e. alternator, AC, belt tensioner, or idle pulley
Spin each one by hand, you can usually tell when a bearing is starting to go

 

[adsm08]

4.0 SOHC doesn't have a cam syncro.

 

[RonD]

Yes, I added that, oops, CPS is on valve cover so no separate drive shaft

 

[MrEvilPirate]

One of the long bolts holding the lower thermostat housing down sheared off as I was trying to loosen it. So no update until replacement parts come.
The new tensioners don't feel any tighter than the old ones.

 

[RonD]

Not uncommon for those bolts to gets stuck and break

The "old ones" may be "new ones" if a previous owner already did the swap.

Rattle can be broken guide, so while older designed tensioner caused the problem newer one doesn't fix previous damage, but keep a good thought, all you can do at this point

 

[MrEvilPirate]

So tonight I'm going to try to get the sheared bolt out. Need to remove fan belt and remove idler pulley to get my vice grips in there. Hope to god it comes out as it looks too small to drill without screwing up the threading.

I want to run the truck without fan belt attached as suggested to see if noise is coming from an accessory. Also both tensioners have been replaced moment of truth I guess.

With fan belt off water pump will not be driven, so is it correct to assume it won't make a difference that I have drained coolant? Plan to only run it for a short while. Thanks.