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04 mountaineer timing


January 8, 2016
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Year, Model & Trim Level
2004 explorer
Have a 04 mountaineer with bad timing chain noise in front. Took of front and found primary tensioner broken. all other parts looked good. Installed new tensioner ONLY. Thought I could get away with it. No way. The new tensioner lasted about fifteen second and the rattle started again. Took it back apartand the brand new tensioner blew apart. Took off valve covers for better inspection and both cassettes appear fine with no broken pieces.Thought that the tensioner may have been no good and reinstalled another one.
Same result. tensioner blew apart again.. Question can just the primary chain be replaced? It appears that the primary chain is stretched enough to rtemove it without loosening jack shaft bolt. Question Is the primary chain suppose to be able to remove without removing the jackshaft sprocket.
It seems that the tensioner flexed too far against the chain to cause it to break
did not undo jackshaft bolt but want to change just primary chai ,guide and tebioner do I need the 6488 tool to do this its kind of a deal breaker(230 for tool). any comments are most welcome

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replacing primary chain, etc.

As I recall even with the primary chain tensioner and guide removed there is not enough slack in the chain to remove it by lifting it off one of the sprockets. That's why it rarely slips when the tensioner has failed. I don't know if there is enough slack in the chain to slide the crankshaft sprocket forward far enough to clear the end of the crankshaft but I doubt it. That means your only option is to loosen the jackshaft sprocket retaining bolt.

I don't understand why the primary chain tensioner is failing so quickly. I assume that you pulled the pin.

Where is it failing?

thanks fo the response. Yes i did pull the pin. The first tensioner had all the spring leaves fall off. In hindsight it appears that the top of the new tensioner had flexed against the chain that it exposed the spring pin from behind the metal flap meant to keep it from falling out. The second one snapped right in half in the center of the plastic from apparrent over flex. I asked the question about whether the jackshaft bolt needed to be removed because i actually got the primary chain and gears off with just the removal of the tensioner and guide. now im wondering if is possible to change the primary chain without having to buy the tools?I believe that the cams should still be in time and was wondering if anyone knew a procedue for changing out just the primary chain

jackshaft position

Since you did not remove/loosen the jackshaft sprocket retaining bolt the timing of the left camshaft relative to the right camshaft will be correct. However, the crankshaft or jackshaft may have moved once the chain was removed unless you kept them in position some way. Was the crankshaft at TDC for piston 1 on the compression stroke when you removed the chain? If not, it will be difficult to check to see if the timing has changed. It is not necessary to purchase the timing kit because if your timing is off it will be in increments of a chain tooth assuming that the timing was correct when you removed the chain. To check the timing the timing slot on the camshafts should be below the axes of the cams and parallel to the head surface that mates with the valve covers when the crankshaft is at TDC for piston 1 on the compression stroke.

The old chain may have been stretched. You may not be able to get the new chain on in the same way you removed the old one.

Bought this truck real cheap to repair. It had the bad rattling when i drove it home. after changing just the primary tensioner it started but made same noises only to find the new tensioner broken. at that time i noticed the balance shaft tensioner was broken also. was able to chnge just the spring and plastic part without removing the pan or engine. Thought i was all set. The primary was loose enough to remove with just the tensioner and guide off.the engine did not turn and i marked it and put it back on..Started but noise returned immediately.also would not rev up properly but did run.
Now the mystery. the cams are not in sync with one cam 180 off from the other the slot on one is above and the slot on the left is below. How could that happen if i didnt loosen jackshaft.now im screwed because i tried to turn it to line up cams and didnt have the guide on and it definately slipped when i turned it.now if i pull the engine out to change every thing i wont be able to turn motor to remove torque converter bolts any ideas on how to accomplish without bending valves have only been working on cars for 45 years cant believe this one

maybe not your fault

The SOHC V6 will start and run (but not well) with cams 180 degrees out of phase. It happens fairly often when people (even shop personnel) not familiar with the engine perform repairs. The instructions are easily misinterpreted causing people to rotate the crankshaft 360 degrees between timing the right bank and the left bank. Your engine may have been like that when you bought it.

First, are you sure the piston in cylinder 1 (front cylinder on passenger side) is at TDC and on the compression stroke? No cylinder 1 valves should be depressed.

If cylinder 1 is at TDC and on the compression stroke then you have to rotate the passenger side camshaft 180 degrees without having the pistons strike and bend the valves. Unfortunately, it takes a special tool to compress the valve springs in order to remove the cam followers which allows the valves to seat. Another option is to remove the camshaft bearing caps, rotate the camshaft, and then reinstall the bearing caps. This is a very risky process since the valve springs exert pressure on the camshaft lobes as the caps are removed and installed. If not being careful to keep the camshaft horizontal a cap will break. Since there are no camshaft bearing inserts a broken cap means purchasing another head with camshaft.

There are camshaft positions that allow the piston in a cylinder to rotate thru TDC without striking the valves. With the primary chain, guide and tensioner installed, to move the right camshaft relative to the left camshaft you could loosen the left (driver side) camshaft sprocket retaining bolt. You can use locking pliers to rotate the camshaft clockwise and counterclockwise to avoid interference while rotating the crankshaft and the right camshaft. It would be a rather tedious, time consuming process but it wouldn't require any special tools. After the crankshaft has been rotated 360 degrees both camshafts would have the timing slots above the axis of the camshaft if you started with the right below and the left above. It doesn't matter whether both camshafts have the slot above or the slot below as long as the they are the same and the slot is parallel to the head surface that mates with the valve cover. You have to be very careful not to force either the crankshaft or the camshaft to rotate since a piston could be pushing against a valve. You should use two locking pliers on the camshaft between the lobes to hold it in place when loosening or tightening the camshaft sprocket retaining bolt to prevent slipping.

I was able to remove and install both camshafts twice without breaking a bearing cap but I was very careful. Other members have not been as fortunate. There is no need to pull the engine unless the rear cassette is broken.

Dont know how they could have gotten 180 off the car was not worked on before the chain rattle started. and I did not take the jackshaft bolt off. will take a closer look at the left cam as the slot is to the rear of the enginr but it felt like it was above axis and the right below. ill let you know but it they are 180 out of sync there must be valve damage??

I would do a compression check if I could. Now with it out of time ill bend some valves. I am not at tdc .I noticed that when I was the key on the crank was at twelve oclock is that correct? If I back up the crank with the chain off you can go slow and tell if there is any contact with valves. could not have slipped that far (turning it with the guide off) so I believe I only went a few teeth clockwise.can I put the cams level with the heads and back up to tdc and put it back on then compression check is that possible.


It would be messy to do a normal compression test with the timing and valve covers removed. Oil would probably be slinging off the chains and camshafts. If you have access to an air compressor and a spark plug adapter you can check for bent/non-seating valves by pressurizing each cylinder when it's piston is at TDC on the compression stroke.

One method I used to check the camshaft timing used an allen wrench and calipers.

You're correct that the keyway in the crankshaft will be at 12 o'clock when piston 1 is at TDC. I found that a manometer is accurate to about 1 degree for finding TDC: Prototype Manometer TDC finder. Of course it won't work with bent valves since there is no compression.

2000 streetrod
I have confirmed that the cams are out of sync.How? I never removed the jackshaft bolt(still haven't) it was used daily up until chain rattle. Can you think of any way they could be 180 from each other. Didn't confirm exactly 180 but it sure appears that its 180.can the cam sprockets slip? cant imagine how it got this way if no one has ever taken it apart before me

not original owner

You are not the original owner. There may have been repairs in the past performed incorrectly. Otherwise, then one of the camshafts slipped relative to the other. It probably happened when the rattle started. Sometimes when a cassette guide breaks a piece will get lodged between the chain and the head causing the chain to slip. Are you sure that one of your cassette guides isn't broken? That could explain why your primary chain tensioner keeps breaking. Does your rear guide look like the one below with the top of the guide missing and the chain has been striking the guide post?

It should look like the one below.

If it looks good then try pulling upward of the top of the guide. If it moves more than 1/16 inch then the lower section is probably broken.

Since you have the front cover off can you see the "finger" of the left cassette guide?

Even on the 2002 and later models it is not reinforced with metal and can break off. Also, the tabs that locate the "plastic" on the guides can break allowing the plastic to move up or down on the metal.

Bought this truck real cheap to repair. It had the bad rattling when i drove it home.
Now you know why it was sold cheap.

streetrodI bought this gem cuz it was gonna be junked so bought it for junk price.the rest is immac I know the owner and she has owned it since new. Also came with a service history back to the first oil change. no real risk involved since i could also junk it but thought there might be a good upside if i could fix it. been working on cars for 45 years but this one has got under my skin. i did try to pull up on the back cassette and it seemed good it moves forwrd and back along the bolt but not vertically. I will recheck. might just take both cams off so that i can get to the coverter bolts and put it on a stand and get it over with. really hate to pull the motor. also just the tools are 225 probably lookin at 6-700 just to be able to take it apart and put it back

oh well

timing tool kit

You don't have to use the OTC-6488 timing tool kit to time the camshafts. The kit just simplifies the process, reduces some risk and increases accuracy. I timed my camshafts without using the tool kit a few years ago. For the past year it has reached 6250 rpm on numerous occasions with 6 psi of boost and I've experienced no problems.

If you pull the camshafts then why would you pull the engine?

It sounds to me like you have purchased a vehicle with good potential. I purchased my 2000 and my 2003 mainly due to body and interior condition because I don't do body work nor do I want to. On both I planned to modify the drivetrain.

Still stuck on how they got this way?? how cold the get out of sync without bending the valves was gonna pull it cuz the heads probably have to come off cant figure out how they couldnt be damaged. even thought it was driven home. after installation of the first tensioner. it still started but seemed way off time as engine would not rev up to high.not as good as when it was driven home. after changing out the second one it started once and would not start again.still wouldnt rev up. so i have been goin over and over it trying to think of why. if the valves were bent it wouldnt start but i didnt hear anything fatal when it ran. maybe ill remove the cams and fill wih air as you suggest at least that woulg remove a possiblity
thanks for all your input

Do you happen to know what year and make engine can interchange with a2004 mountaineer. There is too much wrong info out there but have found some reasonably priced motors only I don't know if they will fit. Is it all based on the vin code? the 8th digit E or K
would love your input

surplus engines

There are some minor differences in different generation vehicles: engine wiring harness, valve covers, crankcase breather, injector insulators, head castings. If you get a 2002 thru 2005 engine there will be less to swap to match your stock configuration. I think the heads were changed around 2004. The later heads have less clearance for the front cassette to be removed/installed. The standard procedure for replacing a cassette in them is to remove the head although their is a possible alternative. I think the exhaust manifold stud spacing may also have changed and switched to bolts.

I wouldn't swap the engine unless you determine that the valves are bent. Any engine with more than 150K miles is a candidate for camshaft timing related failures and engines with less than 150K miles are more expensive.

I have come across several engine that are reasonably priced but I do not know of the fit . I am sure that I can change any of the externals when swapping it out and would obviously use the best of what you get. the engines are a 2000 and a 2001. one has 95k and is cheap enough to take the risk. I just need to know that in will go in without any fatal flaws I don't need another boat anchor haha. I also saw a low mileage 1999. How can I be sure that all of my stuff can be transferred onto an engine that 4 or 5 years older.i have an 04 mountaineer (11/03 manufacture date). This vehicle was bought to make a profit on by selling.I certainly don't want a call back.and will listen to the motors before buying. Just wanted your input on the engines that swap in without MAJOR headaches. I have replaced several of these over the years but always with the same yr motor

engine swaps

This may help: 4.0L SOHC Engine Swap... 97/98/99/00/01/02/03 Motor Interchange (w/ photos)

Any engine before 2002 with the original timing chain related components will not have the improvements incorporated in 2002 and later.

In 1999 Ford switched from a return fuel system with a rail mounted fuel pressure regulator (FPR) to a returnless fuel system with a rail mounted fuel pressure damper and a tank installed FPR. The fuel pressure for the 1999 and later models is about twice that of the 1997 & 1998 models. The fuel injectors may have different flow rates. Your 2004 has a fuel pressure/temperature sensor mounted on the fuel rail and uses a separate fuel pump controller to maintain about 40 psi at the fuel rail.

I always advise others to determine if something is broken before replacing it.

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Finally dragged the mountaineer into the garage (that leaves my 48 chevy outside.
I decided to pull the engine. the cams as you know where 180 out of sync without me loosening the jackshaft bolt. Managed to put it back close enough to rotate engine with out valve contact but feared there was damaged.since they got that way with the engine running. took off heads and surprise!! no damage. Now I am trying to put together a parts list. I have seen complete kits as low as 85 on ebay and 150 for a complete gasket set. My question is that the kit has a single tensioner WASHER that I do not know where it goes??? didn't see it when I took it apart and thought you might have the answer as to where it goes.