Help! with chain tensioner oil leak...... - PeachParts Mercedes-Benz Forum

deerefanatic · #1 01-31-2007, 08:55 PM

Hi guys,

I replaced my chain tensioner with one out of a kit I bought from Diesel Giant a while back........ I haven't been able to get it to stop leaking since...... I've replaced that gasket 3 times... It will hold for 1-3 weeks, then let go and start leaking like mad again...... I've tried copper spray-gasket by permatex, didn't help at all... Got brand new allen-head super hardened (12.9) metric bolts because my old bolts were stretching when I was trying to tighten the thing.....didn't help.......

I'm at my wits end! Every time I have this thing off I take care to scrape the block clean with a razor blade.......... Do I need to do anything else to this upon reassembly?

Someone pointed out that there should be an o-ring in addition to the gray paper gasket..... I have no such oring, nor have I put one in........ Where would it go? I DO have the copper crush washer under the spring cap and it's not leaking from there.........

Also, I'm making sure to tighten it to about 55-60 ft lbs......

Thanks,

dkveuro · #2 01-31-2007, 09:17 PM

You may have gorilla'd the bolts and distorted the flange of the tensioner.
The OE gasket is a graphited type...no sealer required.

.

deerefanatic · #3 01-31-2007, 10:00 PM

Nope, I use a torque wrench...................

Can't get it to 65 ft/lbs (recommended torque) as my cheap allen head socket drivers begin to twist at 59 ft/lbs......... 6 ft/lbs low shouldn't be a problem though...........

Brian Carlton · #4 01-31-2007, 10:34 PM

They usually leak due to a very small piece of the old gasket that's remaining on the head or the tensioner itself. It's easy to miss it.

Or, the tensioner is distorted and nothing is going to fix it other than a replacement.

Ken300D · #5 02-01-2007, 07:16 AM

The old gasket material is hard to distinguish from metal, because it is so hard and the pressure and heat turn it to almost a ceramic-like substance.

With any of the old gasket still there, it becomes hard to get a good seal.

The only way to be sure of getting a seal is to take the surface down to shiny metal. I did this with a cup brush on a drill. Not too hard to do with the thermostat housing also removed.

If you do this, it will seal with a fresh gasket.

Ken300D

deerefanatic · #6 02-01-2007, 09:27 AM

So, you think me scraping it is not actually getting it down to bare metal?

Wire brush till shiny eh?

Does this tell you anything: When I remove the tensioner, the gasket will usually peel off the block in one piece except for a small oil-soaked section about 1/8 inch wide running from the oil supply passage straight to the bottom edge of the gasket, which is where the leak comes from.

sailor15015 · #7 02-01-2007, 10:56 AM

Glad I saw this thread. I just put the tensioner back on my project engine and I spent about an hour with a razor blade and a can of gasket remover and I'm pretty sure its good and clean. I've read that the rule of thumb with gaskets on these engines is no sealant but the surfaces have to be surgically clean. I've spent at least another hour each on the oil filter tower to engine surfaces and vacuum pump to engine surfaces and they're still not as good as I'd like. I definatley under-torqued the tensioner though; I think I used like 30 ft/lbs because I couldn't find the spec in my cd manual.

Brian Carlton · #8 02-01-2007, 09:28 PM

You fellows need to purchase a small flat stone.

Pass the stone over the surface that you believe is clean. If any gasket material remains, the stone will drag against it and it will stand up and shout at you. You can continue to stone the face carefully until the stone removes the remaining gasket material if you wish.

In all of my assembly work with my tooling, I never assemble a perfectly ground surface without the use of the stone. You never know if someone bumped an edge and raised a small bit of steel that you cannot see. The stone will grab it instantly.........

deerefanatic · #9 02-02-2007, 03:32 PM

Really? Where does one get one of these? Or is it the same as you get at the store to sharpen kitchen knives?

Brian Carlton · #10 02-02-2007, 03:41 PM

Quote:

Originally Posted by deerefanatic

Really? Where does one get one of these? Or is it the same as you get at the store to sharpen kitchen knives?

It's similar.

www.mcmaster.com

Ask for "sharpening stone". You can pick from dozens of convient sizes and grits. The medium grit is adequate for most tasks.

mbgizwiz · #11 02-05-2007, 01:45 PM

From the diagram in my manual it looks to me as if there is a small "bleed" hole above the boss which forms the cylinder of the thing. Oil pressure is supplied from below to pump up the unit, but if the bleed hole is plugged up with gasket sealant or something else, the tensioner may be seeing more oil pressure than it needs, which might cause a gasket blowout on the supply side.
Just a thought....

deerefanatic · #12 02-07-2007, 08:42 PM

OK, I got the thing apart again......... I got the block all shined up with a little wire wheel in the dremel........ Pretty darn clean down there.......

While I was at it, I went ahead and changed the timing chain too. Now, just using the cam marks on the thrust washer, I read 2degrees of stretch, which is within the factor of error of those marks.........

Here are some pictures of the tensioner after I got done cleaning it up...... It was leaking between the tensioner and gasket, not the gasket and block.

Does this look like the model of tensioner that should have an o-ring? (See picture 1)

Also, I hear people referring to an aluminum crush washer, I lost mine and DieselGiant where I got the chain kit gave me this one for free. I appears copper. (See Pic 3) Is this ok?

Finally, I've wirebrushed both the block and tensioner with the dremel tool...

Anything else before I assemble tomorrow? Everything look ok? Do I need to get some of that gasket remover solution, or do you think I've got it all?

Finally, we have some thick gasket material in a roll...... I'm wondering if you think it would be ok to make my own gasket out of this to try, as it's thicker and should "squash" down better and maybe fill in any little irregularities. If it didn't work, I still have one original Elring gasket left.........

Lastly, I did check the bleed hole in the tensioner plunger as mentioned that if that was plugged it would cause excessive pressure and maybe cause the gasket to blow out. It's clear and fine.

Ken300D · #13 02-08-2007, 06:49 AM

I would recommend you use the OE-style tensioner gasket. It has a special cut-out for that oil bleed hole that may be difficult to get right with cutting your own. Plus, it could be a good idea for you to buy a new spring along with that gasket since they have been known to fail.

The copper washer you show is for the spring bolt? Should be OK.

Hope you got that new chain master link crimped well - - -

Ken300D

deerefanatic · #14 02-08-2007, 09:05 AM

Ya, I've got the new spring with the new tensioner.......... So only a couple thousand on the spring............

Yep, got that chain crimped down so good that you can't hardly tell it from the rest of the chain......... I rented a press off of a member who wishes to remain undisclosed..........

Glad to hear that crush washer is ok.........

I'm not to worried about cutting my own gasket, I'll use the oe one as a template........ Im just wondering if it will hold up to oil pressure?