I have a 98 SOHC 4.0 with the dreaded timing chain tensioner problem. It was never changed, but managed to go 147K miles so far on original equipment. It finally broke in half. I'm looking for the improved tensioner part number for the front lower tensioner. It seems to be hard to find anyone who has the tensioner in stock, and even then they dont know if its the improved part number. Because I dont have the engine out of the truck, I don't think I can pull the upper oil pan. That means I probably can't replace the chain. Has anyone had experience changing only the tensioner, and does it still take out all the slack from the chain?

Is there a part list breakdown somewhere?

 

yes i have had this problem with my 98 exploder!! no you cant get the top oil pan off unless you yank the moter i learned the hard way. i have the part number somewhere but i cant seem to find it. it was hard for my local dealer to get it right. but if you are going to be taking the moter out i suggest you go aheah and change all 3 tensioners you will be glad you did later. they are a little pricey but when the main one went so did the rest so you might want to check. when you do this you will want to take the moter to a local shop you know and have them time it. it cost me 60 bucks. but the tools to do it were like 500 bucks so i spent the 60 to have a buddy do it. i hope this helps good luck

 

UPDATE:

well since i first posted this thread i've been busy each day after work until about 930 at night every night taking it apart. What I did so far was remove the front of the engine, remove both oil pans, replace the forward chain and tensioner, and reinstalled both oil pans. The upper pan almost comes out, but you have to raise the engine about one inch above the truck. I just worked around the pan hanging. Unfortunately the jackshaft moved, and I saw the front upper chain and sprocket move. This means both cams moved.

Since both cams moved I will have to find someone with the cam positioning tool. I wish there was just a mark or something on the camshaft to line it up. once its lined up I can figure out how to hold it and tighten it. I know that when the crankshaft keyway is pointing up, thats #1 TDC. But as for the cams???

 

*Gasp*

There's a bloke on UK Ebay that advertises replacing the timing chains etc for Explorers.
Just put "Timing chain" in the search bar and it shows up.

 

UPDATE:

I found the tools, one of our flight school students owns a repair shop and one of his guys loaned me the tool!!! woo hoo. I put it all back together, and while lining up the cams I had thought I put it together with the cams both advanced 2 degrees.... THat would have been beautiful. BUT I later found out when the engine wouldnt start that the crank position sensor was in wrong. That meant my number one TDC was not where I thought it was Now I see that my cams are timed 5 degrees retarded. That means I have a retarded explorer. I started it up anyway to listen for noises and check for leaks. It runs fukcing awesome, no leaks, no noises etc. It really sucks that I have to take the intake and rocker covers all apart again. Thats another two more nights of working on it for me. I'm just glad the engine looks so great internally and is refreshed for another 147,000 miles. New chain, tensioner, gaskets, fluids, a/c compressor..... etc.

 

Mate, you are so lucky that you found someone with the tools!

Me, I would've retard the cams a wee if anything, to give it a bit more punch off the line.
I find it makes pretty good power in the top end anyway and it doesn't mind revving.

 

that is a problem i ran into there are no marks and since both cams moved it puts you in sort of a pickle. on the cams themselves the gear at the end. ford said is a friction drive there are no keyways. the tool positions it and then you tighten the bolt weird design. i thought i knew how to do it but i wanted to be 100 percent so i had that part done for me like i said it was 60 bucks not bad. did you look at the front chain guide on mine it was gone and it started to eat into the head and as ford calls it the and i quote "special bolt" was eaten about halfway through that was the noise i was hearing. well let me know how it goes

 

Is it possible to mark the sprocket and cam before disassembly, say, with a punch or a scratch?
I've disassemble a few timing set ups, I usually wire the the chain to the sprocket.

Would that help with an Expy?