Massive Oil Leak

[Bmwz389]

Hey everyone!

It's bean YEARS since I've posted on here, but I haven't had an Explorer ince I graduated college. I picked up a 1998 4.0 SOHC recently that had a no start due to a faulty CKPS. $13 later I was on the road bringing it to work to shake it down. I've only done a few small repairs as it was in pretty good shape, and I am an OCD nightmare when it comes to my cars.

Recently I did both timing tensioners due to slight rattle at idle and a goofy starting issue. I replaced both but unfortunately the noise has not gone away. On Saturday, I replaced the front tensioner. What a pain that was to get to with EVERYTHING in the way. I did not remove the upper or lower intake manifolds.I managed to wiggle the thermostat housing out of the way enough to remove the tensioner. Needless to say, I got it installed and took the truck home. On the way home I was blowing smoke but assumed it to be residual coolant on the motor and manifolds. I drove it to work this morning still smoking like crazy. Here's where it gets bad:

I had it on the lift, whole underside is soaked. Now, after 3 hours of deep cleaning the underbody and engine bay (including the manifold valley), I topped off the oil because it was 2 quarts low on oil. I have reduced the leak down to above the bellhousing, at the rear of the left head. I have watched it twice start to run down the bellhousing ridge against the engine block. BUT, because you cannot see practically anything on the back of the engine, even with a flashlight and mirror, I cannot confirm the source of the leak.

It won't start leaking until a few minutes after running, and once it starts leaking it is a STEADY stream of oil. Almost as if you leave the faucet trickling in your sink. I have lost a full quart of oil just diagnosing it in roughly 30 minutes of run time. I can see it start coming down the cylinder head where it meets at the block but cannot see if it originates above the mating area. It appears that it is coming from above there, but no amount of research, Alldata, YouTube videos or anything else can confirm oil leak points in that area.

I am calling upon the collective to help me out, as this is my daily driver and I need it to get to work. Can anybody point me in a good direction so I am not throwing money in the dark, vehicle torn down outside and having to tow it in and out of the shop?

Thanks in advance!

- Brandon

 

[Terkins]

Seems like one of these might be helpful...? https://www.amazon.com/Endoscope-De...1513063067&sr=8-3&keywords=fiber+optic+camera

This one records video but is more $$ High Resolution Digital Inspection Camera with Recorder

(I never used one...)

 

[boominXplorer]

Double check you put the sealing washer on that tensioner, it will leak like crazy if not fully seated.

 

[XLTrunner]

Yep...common knowledge that if you don't get that washer exactly centered as you're torquing down the tensioner, you'll get a significant leak.

 

[Bmwz389]

The thing is, the tensioner did not come with a crush washer. But what is odd is it does not look like it is leaking from that area, as I do not see oil in the valley of the lower intake manifold. I bought a Cloyes tensioner, which should be a decent manufacturer. Should it have came with a crush washer? The RR tensioner had a crush washer. I thought it was odd, but being as they were the same manufacturer, they did this for a reason.

 

[CDW6212R]

Ditto, pull the right inner fender aside, and R&R that back tensioner, check out the washer for condition.

 

[Bmwz389]

I already replaced the rear tensioner first, and it did come with a crush washer. I am speaking of the FRONT tensioner, it did NOT come with a crush washer. I will contact the supplier and have them send me a new one.

 

[CDW6212R]

Yeah, you need the washers for sure. If you still might have one of the old washers, those can work fine too.

BTW, again be super careful around the sensor next to the front tensioner. Don't put too much pressure on it, do what ever it takes to not hurt the seal of the sensor to the T-stat housing. That's a prone place to leak, or the housing to crack. The repair is to upgrade to the 3rd gen SOHC parts, including the sensors(much better design). I got mine done without moving the sensor, barely.

 

[Bmwz389]

Just an update guys.

I am on my fourth Cloyes tensioner, the second to last tensioner I installed I even used an OEM washer. I did indeed source the leak to the tensioner, using dye and a UV flashlight. Unfortunately, the leak has gotten substantially worse.

I can see it spewing out at the tensioner now, and pours out immediately after oil pressure is achieved. I have thoroughly inspected the mating surface, even cleaned what I didn't think would bother it remotely close to the mating surface. I have thoroughly cleaned every crush washer, and applied a heavy di-electric grease to hold it in place. I made sure not to block the oil passage, and made sure to very carefully watch the "crush" washer to make sure it did not move in the final few screws to set it. I torqued it to 40 lbs and the reused twice one at 50 lbs.

I have had this truck apart over 10 times. I actually gave up on checking for coolant leaks around the 5th tie up. Nothing I do will seal this cylinder head/tensioner. I have inspected the mating surface and it does not look appear to be damaged.

I am going to order in an OEM timing tensioner to compare the designs to see if its really that far off, but I am officially out of ideas on what to do.

Any insight is much appreciated. My truck has been down for a week and only gotten worse.

- Brandon

 

[CDW6212R]

I'm sorry to hear that Brandon. It sounds like something about the tensioner is not mating properly. Do you have the old stock tensioner by chance, to compare with?

 

[Bmwz389]

I do not. It was scrapped 2 weeks ago unfortunately. I will be ordering an OEM unit on Monday to compare them to.

 

[CDW6212R]

I'm still swamped at work, it'll be another week or two before I get to my SOHC valvetrain. I hope you solve it soon.

 

[Bmwz389]

The OEM tensioner came in today but they look identical. Should i be concerned about the markings on the old tensioner? Its only be ran a short amount of time.

The only other thing i can think of is I managed to crossthread 2 inches of aluminum without ever noticing it but thats practivally impossible on fine thread. It would have been a REAL PITA to achieve that.

Would i be safe double gasketing it? It would bring the tensioner away from the head, but would have another gasket.

 

[Bmwz389]

The OEM tensioner came in today but they look identical. Should i be concerned about the markings on the old tensioner? Its only be ran a short amount of time.

The only other thing i can think of is I managed to crossthread 2 inches of aluminum without ever noticing it but thats practically impossible on fine thread. It would have been a REAL PITA to achieve that.

Would i be safe double gasketing it? It would bring the tensioner away from the head, but would have another gasket.

 

[Bmwz389]

It appears the images didnt upload. Ill try again.

 

[CDW6212R]

The mounting surface is what matters the most. That right one in the last picture looks to be not flat at the front edge/corner. If that sticks up much it might have been keeping the washer from sealing fully. Run a good fine file along that mounting surface, by eye you should see whether it's flat or not.

Those marks near the top shouldn't matter, the plunger end pushes inline onto the chain cassette. I'm not sure what along the sides would contact that part of the tensioner body.

 

[Bmwz389]

The thing is, this tensioner on my desk is the second to last one I installed. The one of the vehicle is leaking just as profusely. I wonder if it is just as warped, but will not know until tonight.

Am I missing anything in my install?

• Thoroughly inspect and clean mating surfaces
• Use heavy grease to keep washer in place during install
• Make sure the gasket does not move during install
• Torque to 32 ft lbs (I am torquing to 40 ft lbs due to a long extension and swivel joint) I have torqued a reused gasket to 50 ft lbs

I do not see any damage to the mating surface, no marring. I did see some very light build up and spots of corrosion that I have cleaned off OUTSIDE of the mating surface (observed by the ring on the mating surface), nothing was on the rings mating surface.

I read another post that a guy cross threaded his, but he used an impact and it only went halfway. I can probably confirm I have not cross threaded this lol, as it has all been by hand.

 

[CDW6212R]

I can't think of what else could create a leak there, the two surfaces should be both flat and even. Try putting it in by hand with no gasket first, then the gasket, to attempt to confirm that the mating surfaces are meeting evenly. Do that and know that it should seal right, then put the washer/gasket on and tighten it. I think I used just oil to make mine stay in place, I forgot that detail.

 

[Bmwz389]

How would not running a gasket help verify its flat? Just curious.

Also I took a file to the used one, it was indeed warped, but most of it was probably due to turning a wrench on it attempting to seal it up after the fact with engine running, which may have just set me back?

Here is the used one:

Here is the NEW OEM one:

 

[CDW6212R]

Those look fine, so also look hard at the head surface, where the washer/gasket sets. Look for any deep scratch or nick that could allow oil to pass by the seal, or keep the seal un-crushed.

Putting it on dry assuming you can see much of the area, can tell you if there is any gap between the parts as they touch. It's just an observation to try to identify any issue before permanently bolting it together.

If I thought the leak was from the washer/gasket seal, and it's done it more than once, I'd add a thin film of Ultra Black RTV to all sealing surfaces. That RTV is excellent in any application possible to use it. I hope you are right about the location of the leak, it's still hard to see how the tensioner could leak with a decent washer/gasket there.