MB sealant set up time? MB sealant/timing cover vs. a shrinking head gasket
 

Hi all. I had just enough left in my year-old tube of MB sealant to complete an upper timing cover job. My question to you guys is --- this stuff is still VERY tacky after 24 hours (it's 35 degrees in the garage). How long should I wait before starting the car? I mean, it still has the consistancy as if I just sqeezed it out of the tube!

All old gasket material was cleaned pefectly, and scotchbrited. However, this is on a virgin headgasket motor, and I definitely am fighting the shrinking head gasket/U-shaped seal problem.

Oh yes. This is for my '95 E320. THANKS!!!

I'd say buy a fresh tube. Think of all the trouble of redoing it:eek:

front cover tips
 

Hey Joel! Man, I've done this job four times in three weeks. I've got it down to a SCIENCE! Yes, the beating is cleaning up the old sealant. For sure. And I meant to say, I have two tubes on order. And it didn't make it here before the weekend. And, we've got to have the car operational monday...so I might be doing the job again next weekend...

A few tips for anyone -- and please follow at your own risk ;)

1) I don't pull the cooling fan until after I remove the switchover valve and engine lift hook (two items bolted to the front upper cover). But, I remove the coolant crossover pipe too. Then, I remove the cooling fan. It's really easy to lock the cooling fan pulley (using a 1/4"? bent rod) with all these items out of the way.

I can pretty much have the front cover in my hand in 60 minutes.

2) The timing chain rail (with the guide pin) - it's easy to remove after the front cover is in your hand. I just use a 3/8" drive deep well socket (depending on how long your bolt is), a bolt that will thread inside the pin and a washer. Bolt/washer go through the ratchet end of the socket, the socket goes over the pin. Thread the bolt into the pin and tighten with a ratchet. The pin will slide out --- it's really quite long, and you may have the pull on the socket (with bolt going through) as you tighten the bolt.

If anyone is considering this job, it's really quite simple. You never need to pull the serpentine belt - thankfully. Just the valve cover. Simple stuff.

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I'd appreciate any more opinions on the sealant. Thanks again, Joel.

If you're talking about the "pinkish" colored stuff used to seal machined surfaces where no gasket is needed, it won't cure until it gets hot.

ILUVMILS, I'm talking about the stuff Phil sells here at Fastlane --- it's black in color. The part # is: 003-989-98-20-10 / A 003 989 98 20 10 /003989982010.

What is your experience using this stuff? It's been over 24 hours since I applied it - and I have a hair drier :rolleyes: on the area now (28 degrees outside in Dallas). Thanks!

I don't recall the part# of the MB stuff but you've probably got the same thing. It "cures" about as quickly as the job can be finished. Can you imagine an automotive sealant that required an excessive amount of time to cure before the car could be used:eek:? By the way, if the stuff you've got is the same as MB sells, it works great.

Yup, I checked in WIS and 003-989-98-20-10 is the good stuff. Put the hair dryer away and drive the car.

ILUVMILS, well --- no luck. She's still leaking. But, I'm crossing my fingers/toes that once the new sealant arrives, and I do the job again, the stuff will cure much faster and will hold. If not, I'm pulling the head and will fix it for the last time..... man! Thanks again.

MB sealant -- my old tube no longer works
 

ILUVMILS --- Ok, my order arrived today and I put a gob of the new MB sealant on my work bench next to a gob of the old MB sealant. I also smeared a thin layer of the old stuff next to a thin layer of the new stuff.

Right out of the tube, the old MB sealant is very glossy in color - looks wet. The new tube of MB sealant is kinda matte in gloss. In about an hours time, the new stuff is really tacking nicely --- firming. THIS is what I've needed!

I think my old tube was just old, and something must've happened to it chemically. For my new tube, I'll keep plastic wrap over the cap/end, to keep the air out. And I'll keep it in the house instead of the garage.

BTW - the part number on the old and new containers are as you listed.

Thanks again.

That's interesting. Here at the dealer, we never have a tube sitting around long enough for it to go bad. Thanks for following up.

71Rcod,

Ya want to do another one? Just kidding! It's on my list when the weather gets warmer.


Michael

Front cover still leaking !!
 

Man, this is depressing. Fifth time resealing the front cover gasket, and she's still leaking. Even with the great MB sealant, it's dripping just above the AIR pump on the lower corner where the head meets the front cover. So, it's time to pull the head.

---- OK, the cylinder head removal. This is a virgin motor (90k), and I have the new-style head gaskets in the garage. But, just want to be sure on the process.

The front cover/timing chain rail pin is NO problem. I'm a pro at that. :rolleyes: It really looks like I need to loosen the EGR/exhaust manifold pipe (RH side), remove the wiring/intake hose clamps from the (LH) side, mark the chain location on the timing gears, pull the air pump out of the way to loosen the chain tensioner, remove the exhaust sprocket, tie the chain to the side rail -- and pull the head.

I'm really unsure about:
* what on the intake side I need to pull. - I plan on pulling the head/intake/exhaust manifold together.
* and would really appreciate any tips anyone could pass along that would save me time.

Many thanks!!!

Take the intake manifold off. It's easy. Trying to pull the head with both manifolds attached will be a real juggling act.

ILUVMILS,

Thanks again. I really appreciate your advice. I'm already about 1/2 of the way. Hope you don't mind, but I have couple questions for you:
* what size/type socket/bit are the head bolts? I don't have anything with that many points. Not a problem, as I can run out later and get what I need. Just wanted to make sure to get the right thing.
* I'm going to break the two bolts holding each 1/2 of the manifold (cylinder 1-3 / cylinder 4-6). And will pull the head with the exhaust manifolds in place. Looks a bit daunting to remove all the manifold-to-head nuts. Does this sound good?
* Intake side -- Looks pretty straight forward. I moved the wiring harness out of the way, and am about to disconnect the fuel rail. Should I not do this? (taking all precautions, of course, to make sure the fuel system doesn't try and charge) Or, should I simply unbolt the intake manifold and leave the fuel rail in place?

From there, it looks really straightforward. Again, THANKS. I definitely want to do this right.

Ok, just to follow up. Pulling the head is whipping me :confused: I removed the intake (broke the two hose/mount locations under the intake - will have to JB weld them back on. Had a terrible time removing the intake - the last bolt at the bottom next to the firewall is hidden by the fuel rail, or a part of the fuel rail. I'll have to go out later and get the correct socket for the head, but don't know if I'll find it on a Saturday.

Tomorrow morning, on the agenda:
* unbolt the exhaust manifolds from the head pipes
* remove the AIR pump (funny, just installed a rebuilt one three months ago) so I can get to the chain tensioner
* mark the timing chain
* loosen anything else small that I need to unbolt the head
* get the socket!

Wish me luck, guys.

O.K., good luck. :P

Sounds like I'm a bit late, but for what it's worth. The fuel rail can be removed without dis-connecting any fuel lines. The two allen bolts on each end of the intake need to be removed as well as the middle one. The rail can then be pulled out and laid up on the cowl area. Just make sure the O-rings don't pop off the injectors and stay stuck in the manifold. If this happens you'll never get the rail back in properly. A Snap-On 1/4" drive 6mm allen swivel, used with a 3/8" to 1/4" adapter is perfect for dealing with the intake bolts. Crack em' loose with the 3/8" drive and run em' out with the 1/4" drive.

Don't use JB weld to repair the vacuum nipples on the intake either. Some screw in fittings with tapered pipe threads are much easier, quicker and will last forever.

Before you re-install the intake manifold, reposition the the two clamps so that you can get at them with a long #2 phillips from the front, UNDER the intake runners. It makes tightening them a breeze. Good luck

head gasket -- ready to pull the head
 

ILUVMILS,

Better late than never! Thanks for the tips. Fortunately, I left the fuel rail on the intake. And thanks for the tip on the vacuum nipples on the bottom of the intake. You know, the plastic is so broken away, I'll probably need to use JB Weld to heal over the plastic, and then drill for the new "threaded" nipples as you suggest. It was as if the rubber hose was welded to the intake, and they broke so easily.

I made another mistake I'd appreciate your advice on. For some reason, I was thinking I needed to pull the intake cam gear (drivers side of the motor), and I removed the small bolt (spring loaded) and collar, and turned the large nut in the center of the cam gear. It moves about 20 degrees or so back and forth. And when I did this, I could hear compression leaking out. How do I get things repositioned again? Can't believe I did that.

Now, the exhaust timing gear is off and I'm ready to pull the head. My only problem, I can't find the M12 XYN socket anywhere locally )in Dallas!). Can't believe that. So, I'm going to order a set from this place:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7543057683&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

ZDMAK

Thanks for this tip "A Snap-On 1/4" drive 6mm allen swivel, used with a 3/8" to 1/4" adapter is perfect for dealing with the intake bolts. Crack em' loose with the 3/8" drive and run em' out with the 1/4" drive."

What great tips. I greatly appreciate it!!!

71Rcode

Don't worry about the intake cam gear. If you didn't loosen or remove the "large nut in the center" you're OK. That's the cam advance mechanism. It's supposed to be able to rotate a few degrees, independant of the exhaust cam. The "compression" you hear leaking out when you turn it is actually motor oil being pushed out. It sounds like you've only removed the plunger/valve that supplies oil pressure the advance mechanism. Just put it back together the way it came apart and forget it.

Since we're talking about the cam advance mechanism, here's another tip you may find helpful. Once you've got the head off of the engine, lean it up against the wall in the corner (so it can't fall over) with the front up and the mating surface facing you. Look at the bottom, on the left side. You'll see the bore (this is why they leak oil at the right rear of the engine) leading to the main oil passage, which leads to the advance mechanism. Turn the advance mechanism back and forth a few degrees. You'll notice quite a bit of oil coming out of that bore. While you're prepping the block for the new gasket, let the head drain. Turn the advance mechanism a few degrees every so often. This will vent the passage and allow more oil to drain out. If you don't do this you'll have dirty oil coming out while you're re-installing the head.

You've still got lots of work to do, so be patient. Remember, the tear down ALWAYS takes less time than re-assembly.

ILUVMILS, thanks again - great tips!

Ok, the head is back on. I won't be able to proceed with the intake as I'm going to tap the broken area on the bottom as you suggested, and I need to get the heater core hose to the back side (drivers side) of the cylinder head. But I want to get things as close as possible.

My new questions:
* The timing chain tensioner won't go in all the way. I reassembled it and installed it in its most "compressed" state. Of course, I did this with the cam gears aligned to the paint marks I made on the chain, and I never moved the crank. With as much slack as possible in the chain on the passenger side (side of the chain tensioner), I installed the chain tensioner. The problem is the tensioner won't screw in all the way -- as the chain is too tight. With a tight chain, I rotated the crank by hand. I thought that might free things. But the chain is still is tight. What did I do wrong? The tensioner plunger is totally "plunged". But I've got about 1/4" to go on the tensioner to seat it.

* and here's a dumb one -- torque specs.
1st step: 56 Nm (what is this in foot pounds)
2nd step: 90 degrees
3rd step: 90 degrees

What is 90 degrees. Surely this doesn't mean moving the torque wrench a full 90 degrees from the 56 Nm, or does it? Again, THANK YOU.

71Rcode

Ok, I found this post -- and this explains the head bolt torque:

"1st iteration: Following the sequence laid out in the diagram for the 14 head bolts, you torque them to 55 N*m (about 41 lb*ft).

2nd iteration: Starting over at Bolt #1, you goe through the torque sequence again, only this time don't use a torque wrench. Switch over to a breaker bar so you don't damage your torque wrench, or else set your torque wrench as high as it goes. You then tighten each bolt in sequence with a 90 degree rotation. No torque measured, just tighten the bolt 90 degrees, or 1/4 turn.

3rd iteration: Start over at Bolt#1 and repeat, tightening all 14 bolts again, in the proper sequence, another 1/4 turn or 90 degrees. Then you are done.

This is what I mean by 'torque to yield' bolts, or also called angle torquing. You are actually going beyond the elastic region of the bolt material's stress, into the plastic region. Once you get to the yield point, the torque will actually change very little as the bolt gets stretched. This is why it is important to either replace the bolts, or make damn sure they are within the specified allowable stretch limit before you start."
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But, I'm still stuck on the timing chain tensioner. And am open to suggestions! As soon as I get a chance this afternoon, I'll go back out with a fresh head and see what's going on.

Also, I *need* to measure my head bolts.

Crap! Just looked at the CD manual entry for the chain tensioner. Now things make better sense. I never removed the end cap on the tensioner. I'll give it a shot later today.

There's a few different ways to deal with the chain tensioner. It just depends on who you ask. Try this. Using a new aluminum seal, install the "body" of the tensioner and tighten it. Then, install the rest of the internal parts. The trick is getting the threads started. Working against the spring tension is a bit tricky sometimes, but with a little patience you'll get it. Once it's all together, turn the engine over by hand several times and re-check the cam timing, just to be sure. Taking stuff apart twice is a PIA.

ILUVMILS,

Funny you mentioned that, as it's exactly the way I tried it early this morning and it worked. Now I need to turn the motor and check the cam timing. Interesting note, the tensioner housing was tough to thread in. I don't know why, but it didn't feel like it was binding or stripping (as it went in perfectly), just really tight going in and seating.

I'll go out in the garage now and spin the engine by hand and recheck the timing.

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On another note, I think my head bolts have stretched too much.

According to the CD manual, new bolts should be 160 mm
Maximum bolt length is 163.5

I checked one bolt: 6 11/16" = 166.85

So I'll have to order them. Thanks again for the great post. Your expertise has been invaluable. Thanks for sticking with my dumbA questions !

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I want to get this thing as buttoned up today as possible (bolt on exhaust manifolds, install front cover) --- but probably shouldn't until I torque down the cylinder head. What do you think? I have the original "stretched" bolts holding the head down --- they are only snug.

Thanks again!

Get the head torqued down first. Wait about 10-15 minutes before giving them the first 1/4 turn, same for the next. Since you removed the head and the exhaust manifolds together I assumed you'd re-assemble the same way. It's a whole lot easier to install the manifolds with the head on the workbench.

Anyhow, now is when you want to TAKE YOUR TIME. Make sure everything is properly fitted, connected, and tightened. The last thing you need is a CHECK ENGINE light coming on after you've finished. I've seen it happen to experienced techs'. A vacuum line left off is the most common mistake, so double-check everything.

Got it -- I'll wait for the new head bolts. And I pulled the head with the exhaust manifolds bolted up. So I'm all covered there. Thanks for the great tip on the torque (time in between).

Another question - top dead center. Using a screwdriver *carefully* in the #1 cylinder head, the piston is reaching TDC as it's supposed to (according to the cramp damper marking). My question is this: both valves are closed when I'm on TDC, and TDC is just after the exhaust stroke, correct? In other words, I'm on TDC just **after** the exhaust valve closes, and just **before** the intake valve opens?

And, how do I check the cam gears when I'm on TDC to make sure they're dead on? I didn't see any indents or marks on them. I guess I could continue to rotate the assembly until I hit my "paint" marks that I used on the chain/sprockets.

Many thanks! 71Rcode

Ok, I went as far as I could without the head bolts. They should be here about the middle of the week, along with the heater hose and a couple of the intake hoses.

Regarding the my timing question (cam gear location), I turned the crank by hand a few more times, and my original alignment marks on the sprockets/chain (also marked both timing chain rails just for the heck of it before disassembling), and all were dead on. So, I can only guess that I'm good to go.

I'll let you guys know how it turns out with my broken intake manifold vacuum ports.