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Topic: My M-11 exhaust manifold gasket replacement (Read 1314 times) previous topic - next topic

My M-11 exhaust manifold gasket replacement

We have had a small exhaust leak from between the head and exhaust manifold on our 1998 U-320, with M-11.  About a week ago, I decided it was time to repair it.  As it was, the only signs of a problem were a small soot patch, and a hissing sound when accelerating.  It made no unusual noise when idling.  My worry was that the leak would suddenly grow larger, and compromise the turbo boost.  Then I would be at someone else's mercy.

I started by spraying the manifold bolts A LOT with CRC Freeze-Off.  I tapped on the bolts, and I ran the engine to warm.  I did this all a couple of times.  I used about 1.5 cans of the Freeze-Off.  I then let it sit for over a week.

I went to the bolts very gingerly.  I turned until I felt the click of movement.  Then I sprayed it again, and waited about half an hour.  Then I turned it back to tight, and gave it another shot of spray.  Then I carefully loosened it about ¼ turn, and went to the next bolt.  I worked from the outside in.  After all of the bolts had about ¼ turn loose, then I started removing the bolts, one cylinder pair at a time.  I chased the bolt threads, and reinstalled them loose and without the spacer that each bolt has.  Not one bolt broke!

When all of the bolts were removed and loosely replaced, I used a crowbar to gently pry the manifold away from the head.  I was able to get about ¼ inch space.  All of the gaskets came out cleanly and in one piece, except the one that was leaking.  It came out in pieces, and I did my best to make sure all of the pieces were there, and not in the manifold or head!

To install the gaskets, I used a chopstick!

I used a piece of a chopstick to run through the top hole of each manifold port attachment flange.  I carefully ran the stick through the top hole of the gasket, so it would dangle in place.  Then I loosely installed the bottom bolt with the spacer.  Then the top bolt.  All bolts got a good smear of anti-seize.  Much of this was done while kneeling on the rocker cover, with my head resting on the transmission dipstick tube, and looking into a mirror.  All was from the top, none from underneath.  While I went, I used a thin wire bottle brush to clean off the mating surfaces, before placing the gasket.

I adjusted the placement of the crowbar as I worked, getting a maximum gap, and keeping it out of the way of hands and eyes.

When all twelve bolts were loose fit, I snugged them down and took a break.  I followed the instructions for torquing in the specific bolt sequence to 20 ft-lb and then to 35 ft-lb.

I tried to disconnect the exhaust pipe from the turbo, but it didn't want to move.  Turned out to be OK.  I did remove the rubber hoses from the turbo, but I don't think that was necessary.

I have not taken a test drive, but so far all looks (and sounds) good.
Matt B
1998 u-320

Re: My M-11 exhaust manifold gasket replacement

Reply #1 –
It's scary how good a person gets some times.  Good job. 
Freightliner MT55 w 24 ft box
All aluminum.

Re: My M-11 exhaust manifold gasket replacement

Reply #3 –
Thanks for the overview. Did you use the original bolts or purchase new ones. I did the same job on my old M11 but was recommended to install new bolts as I was told that the old bolts could break after the manifold heats up and causes expansion. Not sure how accurate the info is, but I bought new bolts just to be safe.

Pat

Re: My M-11 exhaust manifold gasket replacement

Reply #4 –
Quote from: pibutler –
Thanks for the overview. Did you use the original bolts or purchase new ones. I did the same job on my old M11 but was recommended to install new bolts as I was told that the old bolts could break after the manifold heats up and causes expansion. Not sure how accurate the info is, but I bought new bolts just to be safe.

Pat
Good question!  I reused the old bolts.  Had any of the bolts been broken or distorted, I would have replaced them all.  All of the bolts looked good, and gave no serious resistance when I chased the threads with a die.  I have read that the bolts get fatigued from the normal heat-cold cycle, but those saying that were talking about engines with 500K miles or more.

I will let you know!

Matt B
1998 u-320

Re: My M-11 exhaust manifold gasket replacement

Reply #5 –

Matt did you reinstall with anti seize? I can't over emphasize how important it is. The bolts have been disturbed and cleaned they genuinely need for the next removal. Removing broken bolts and studs from heads can really be prevented. It's expensive and can even include repairs to the cylinder head if improperly performed.
Amazon.com: Never-Seez NSBT-8 Silver Gray Regular Grade Anti-Seize Compound,...
Used this for years on turbo charger mount bolts with great results.
Amazon.com: Never-Seez NSBT-16N Silver Pure Nickel Special Anti-Seize...
This is my current favorite. Used in aircraft turbine hot sections and I have yet to see stainless fasteners fail if used. Gaul and fail without.  Doesn't take much, but will make a world of difference. Good stuff
Scott

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: My M-11 exhaust manifold gasket replacement

Reply #6 –
Quote from: dsd –
Matt did you reinstall with anti seize?
Absolutely!  I put that goo on 'most everything, unless I want it to be forever.  It can make the difference between working a broken bolt out with the tip of an awl, and paying a shop for a Helicoil!
Matt B
1998 u-320

Re: My M-11 exhaust manifold gasket replacement

Reply #7 –
I just bought a can from here a little cheaper and free shipping.

BOSTIK NEVER-SEEZ Pure Nickel Special 1Lb. Bush in Can NSBT-16N FREE EXP...
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: My M-11 exhaust manifold gasket replacement

Reply #8 –
Quote from: oldmattb –
All of the bolts looked good, and gave no serious resistance when I chased the threads with a die.  I have read that the bolts get fatigued from the normal heat-cold cycle, but those saying that were talking about engines with 500K miles or more.

I will let you know!


Matt,

Good that you were able to re-use the manifold screws. You probably won't have any issues with them. For future reference, avoid running a die down screws that are highly stressed, or subject to heavy thermal cycling. Screws have rolled threads and a die could cut some material from the rolled fillet radius, near the root of the threads, causing a stress riser that will reduce fatigue life.

Greg
Greg & Cathy
2000 U320 4010 DGFE Build #5650
Had: 1999 Tradewinds 7370

Re: My M-11 exhaust manifold gasket replacement

Reply #9 –
Quote from: MisterEd –
Matt,

Good that you were able to re-use the manifold screws. You probably won't have any issues with them. For future reference, avoid running a die down screws that are highly stressed, or subject to heavy thermal cycling. Screws have rolled threads and a die could cut some material from the rolled fillet radius, near the root of the threads, causing a stress riser that will reduce fatigue life.

Greg
I didn't know this - very interesting.

Maybe I had a sense of it.  If the die had removed any metal from any of the bolts, I would have replaced all of them.  I held the heads of the bolts with a 4-inch wrench for comfort, though I could have likely held them with my fist  My intention was to clean the junk out of the treads, and check for distortion.
Matt B
1998 u-320

Re: My M-11 exhaust manifold gasket replacement

Reply #10 –
So, guess the golden rule is to spray the bolt to cylinder head area the day before with Brett's patented ATF/Acetone 50/50 mix and if any of the bolts look sketchy, replace them and the use Chuck's Bostik never-seez on the threads. Or, for the price, just replace them with new to begin with.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: My M-11 exhaust manifold gasket replacement

Reply #11 –
Quote from: oldmattb –
I didn't know this - very interesting.

Maybe I had a sense of it.  If the die had removed any metal from any of the bolts, I would have replaced all of them.  I held the heads of the bolts with a 4-inch wrench for comfort, though I could have likely held them with my fist  My intention was to clean the junk out of the treads, and check for distortion.
If the threads were rolled you would have either ruined the die or gave up after a few. 
Freightliner MT55 w 24 ft box
All aluminum.

Re: My M-11 exhaust manifold gasket replacement

Reply #12 –
Quote from: Pierce & Gaylie Stewart –
So, guess the golden rule is to spray the bolt to cylinder head area the day before with Brett's patented ATF/Acetone 50/50 mix and if any of the bolts look sketchy, replace them and the use Chuck's Bostik never-seez on the threads. Or, for the price, just replace them with new to begin with.

Pierce

I've had very good luck with a stuff called Mouse milk
Amazon.com: Mouse Milk Oil 8 Oz: Home Improvement
And second choice
Amazon.com: Kano Aerokroil Penetrating Oil, King Size, 13 oz. aerosol...
This was over a decade of removing/installing turbo chargers/wastegates in Cessnas with 1700- 2200 hours of abusive charter use. You could always tell others work from your own in removal after completion of service life in how they come apart. Mouse milk out performed everything I tried every time. I never disassemble current prior work any more, it is removed off wing and sent to the shop, but you can always see the difference in others. Nickel anti seize is outstanding stuff. IMO
Scott
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: My M-11 exhaust manifold gasket replacement

Reply #13 –

Scott,

It gets rave reviews at Amazon.com: Mouse Milk Oil 8 Oz: Home Improvement  Chief aircraft has it for $6 in Oregon but won't ship it to California because of the VOC. I might try Amazon.

Pierce

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: My M-11 exhaust manifold gasket replacement

Reply #14 –
I watched several videos before I got started.  This one really resonated.  He starts out kind of goofy, but has a great message.

https://www.youtube.com/watch?v=9PKNCVXvZ6w
Matt B
1998 u-320

Re: My M-11 exhaust manifold gasket replacement

Reply #15 –
Pierce, Amazon has it
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: My M-11 exhaust manifold gasket replacement

Reply #16 –
Yes, I noticed it but they were almost 3X the price and I'm not sure they will ship to CA. Because of smog, we can't get a lot of paint, etc. At least Chief was up front about it. A lot of others just cancel the order.

Chief always has good prices, Aircraft Spruce too down in Chino, CA. Summit Racing has a big store in Reno so people always go over the hill for the high VOC stuff.

I just bought a really nice ML350 for $800 with a bad cat converter in Reno. The entire exhaust system is different from our identical CA vehicle and you can't believe what California cat converters cost. I can't smog without them. They have a special tamper proof shell so every other year, they better be installed. And 5 cats on a 6 cylinder car, 4 O2 sensors.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)
 

Re: My M-11 exhaust manifold gasket replacement

Reply #17 –
I only found my manifold leak after noticing a manifold bolt head missing.  During the work another broken bolt was found.  It took a lot of work to get the broken pieces out.  I never would have re-installed old bolts after all that work.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R