Motor Seized up

[ndaniels1987]

I recently purchased a 2002 Explorer 4.0. I went out the start the vehicle on morning and the motor only turn maybe half a turn then I heard a loud clunk. So my first thought was the starter. I removed to the starter took to a local parts store and had it checked. It is a good starter. I have power down to the stater so I knew that wasnt the problem. So I decided to turn the motor by hand. I removed the plugs and put a breaker bar on the crank nut. Nothing Happened. I removed the lower oil pan and found some plastic looking parts and a couple peices of metal. After doing some research I found out the parts look very similar to the timing chain tensioner.

So my question is, Is it possible to replace the timing chain with out removing the engine from the vehicle? I have already removed the radiator and am now having trouble removing the Fan and Fan clutch any info will be appreciated.

 

[Peck]

no to change the rear chains u have to remove the motor

 

[rickybobby]

you can change the rear chains with the engine in, but you have to remove the transmission. It is a lot more work to do it that way though

 

[ndaniels1987]

Wow I didn't know there where chains on the rear. Looks like I need to invest in a repair manual. Thanks

 

[ndaniels1987]

In hoping the front is all I need to replace.

 

[1Aauto]

welcome to the site

 

[2000StreetRod]

which tensioner?

If your vehicle has 4WD the engine has four timing chain related tensioners. There will never be parts of the left or right camshaft timing chain tensioners in the pan because they are hydraulic cylinders. There could be pieces of the guide assemblies in the pan. The right (rear) cassette (includes guide assembly) requires removal of the engine (preferred) or the transmission to replace. The left cassette can be replaced with the engine in the vehicle.

The primary (crankshaft to jackshaft) chain tensioner is made of leaf springs in a plastic frame mounted on a metal base. It can be replaced with the engine in the vehicle.

The balance shaft chain tensioner is also made of leaf springs in a plastic frame mounted on a metal base. To replace the entire tensioner assembly the block girdle (upper oil pan) must be removed.

I suspect the pieces you found are from either the balance shaft or the primary chain tensioner. However, when either of those tensioners fail it is uncommon to result in engine lock up. I fear that either the primary chain broke or one of the camshaft chains slipped. Since the SOHC V6 is an interference engine either occurrence could result in valve/piston damage.

I suggest not spending any money on replacement parts or purchasing a timing tool kit until the damage (if any) has been determined.