6.9 Blown Head Gasket

[BIG 450]

Hi All in W116 Land,

As the topic suggests, my 6.9 has blown a head gasket. From consensus within the few MBCV members that attended the M-100 Down Under Rally - the heads were cooked on the drive up to Echuca when I had a bit of a major cooling problem that involved topping up the system with water nearly at all stops. RobertD can shed some light on this. For the couple of weeks after the car seemed to run all right and didn't need that much topping up of fluid then one Sunday morning it just started blowing steam out the back and was having to good a time doing it and refused to stop, it has not been run since. I checked the oil filler cap at the time and there was a milky white emulsion forming there that indicated to me straight away that water is mixing with oil. 

Consensus from the people I have spoken to up to this point have confirmed it's a head gasket and it needs to be replaced along with a clean of the oil pump, lines and sump to get all the emulsion out. The radiator needs to be fixed as that is leaking and I might change the hoses and overflow tank whilst I am at it.

Since I am sourcing the parts myself to have them ready for when I get enough cash aside to get someone to do the work (I am considering doing it myself as it's a great opportunity to learn more about the engine) I wanted to ask what else should be checked, changed over or replaced whilst the heads are off?

At this stage the heads will be cleaned up and the gaskets and other associated seals will be replaced along with the valve stem seals but what else would you recommend doing whilst it's open?

Another couple of things, does anyone have or know of a 6.9 engine manual similar to the W116 Service Manual Library here on the site for sale or at least an electronic copy floating about? Also any recommended/unusual tools that I should source before starting the job?

Thanks in advance for any advice you guys can offer - in no rush as i can get around on two wheels for the time being but I do miss being behind the wheel of the W116. 

Regards

Paul

[CraigS]

Any idea what bank it is blown on ? I wouldn't mind betting it is the left bank, and between 1 & 2 or 2 & 3. This seems to be a weak point, and caused by the head slowly loosening. They should be torqued down periodically, but of course, no-one does it.

What you will need or want to do will depend on the mileage and what you know has been done. For example, when was the timing chain/tensioner/guides checked/changed ? Engine mounts ? Since you need to replace both head gaskets, you will need to remove the brake booster. While that is out, you have a better chance to check the engine mounts, and the front stabiliser bar bushes, and replace them if necessary. Similarly, replace all of the vacuum lines at the same time.

I bought one of my 6.9's with a blown head gasket. Fortunately, there was no damage to the heads (and I suspect your's will be similar), so I replaced all of the above at the same time, as well as the valve guide seals, etc. Cost for parts, and a little bit of labour, was $2,500, so that will give you a bit of an idea what you are up for. That was of course buying the parts from the US.

Only thing you need to be cautious of, if doing it yourself, it to make sure that you can finish the job, otherwise you are going to have to put it on a tow truck to get it somewhere. Having said that, none of it is complicated. There are plenty of procedures on the M100 site.

[oscar]

I'm probably stealing koan's thunder here (sorry koan ) but check out koan's head thread and gallery link

[koan]

I wanted to ask what else should be checked, changed over or replaced whilst the heads are off?

First thing would be a look at the spark plugs and do a compression test to verify that head gasket is the problem. A remote possibility is an inlet gasket leak letting water into the cylinders - unlikely but possible. What's happening in the radiator, blowing out water or bubbles?

As it's quite a big job and a pair of head gaskets are about $500 I'd consider having a valve job done while the engine is in pieces, cost would be somewhere between $500 and $1000 depending on what's needed in the way of guides.

Removing sump and oil pump is a major task in itself, I wouldn't worry about flushing oil lines and the pump. Unless you work at lightening pace by the time it goes back together there'll be no oil in the pump or lines and any dampness remaining will be driven off when the engine warms up, maybe do an extra oil change after a 1000 km.

Another couple of things, does anyone have or know of a 6.9 engine manual similar to the W116 Service Manual Library here on the site for sale or at least an electronic copy floating about?

Don't think there was ever a printed M100 manual, only the microfiche and poor quality paper reproductions of it. "Motor Book World" in Burke Rd (now in Canterbury Rd I think) might be worth trying.

As far as what else is required I could list many parts and lots of useful tools. I'm halfway through this job and there's lots of things I could suggest but the post would go forever, ask questions or PM me.

koan

[CraigS]

I also forgot to add - a new thermostat.

[TJ 450]

Regarding the tightening of head bolts, I know Koan now has a bent Allen Key, but is there a tool available off the shelf that will clear the camshaft?

Tim

[BIG 450]

Thanks for the responses so far guys - much appreciated 

@ CraigS
The timing chain and tensioners were replaced in April of this year after what happened with the 280 along with some work done on the lifters. The brake master cylinder and brakes were done also. The milage on the car is just under 210 000 kilometers. I don't know what bank the gasket has blown on as yet but should have that sorted in the next few days. The thermostat was changed in April also so i guess i can test it out to see if it still good but I think a new one will be in order.

@koan

The radiator was basically squirting coolant out the top right corner and was leaving it's marks everywhere within the engine bay. The overflow tank also got a crack in it near the cap and there was some leakage there also - very minimal though. Compression test is happening tomorrow or wednesday - just waiting for my mate from work to bring his pressure gauge in (former mechanic). I should have one on hand - another thing to add to the shopping list.

The valve job has also been suggested and looks like i will go down that way. Gasket set is on the way and your right considering the price of them - best to get the job done right now rather than having to get another set should the heads need to come off again.

I have read your thread with much interest and the pictures have given me a better understanding of the task at hand. I will get in contact once the ball starts rolling on this regarding the tools  and all the little bits.

Regards

Paul

[WGB]

Commiserations.

An electronic copy of the 6.9 engine manual is available at http://www.schiffeuropean.com/

You can also purchase a copy of the 6.9 transmission manual at this site.

I have a copy of the 6.9 engine manual that I purchased from this site and it is in a peculiar TIFF format with the pictures in negative.

The TIFF files can be easily converted to Adobe Acrobat if you have a copy of this program or you can get a free tiff viewer on line. The one I have even turns the negative photos into (crappy) positives.

Bill

[John Hubertz]

You know, it may be sacrilegous but I'd be mighty tempted to try torquing the head again...  driving it... torquing it 10 ft lbs over spec...  driving it... 

...and since I'm just an ole Kentucky hillbilly at heart I'd even toss a thumb-sized container of that silver dust sealant into it - between torquing #1 and torquing #2....  you'll need the cooling system pressurized of course - maybe just plug the overflow while doing the dirty deed...

...and if it stops foaming at the mouth fix the overflow and run the bugger with good fuel and see how it goes.

"Don't fix it if it ain't broke, and if at all possible, don't fix it even if it IS broke!" 

I have so enjoyed my sledgehammer/axehead curly window regulator gear repair - every time I run that booger up I get a Kentucky chubbie.

Here's one for you Country Music fans...

...You know how you can tell Loretta Lynn wasn't from the Tennessee side of that mountain valley she was raised in?  Cuz the twins have the same Father!


Here's an example of this type of reasoning: 

Fort Jesus- Nestled in the quiet hillbilly magnificence of the Ozark mountains sits the quietly inbred community of Fort Jesus, Arkansas.
For generations this sleepy town has slumbered through the tumultuous revolutions of history and has been perfectly content with the quiet anonymity that isolation and a fondness for shot guns brings.

Things changed suddenly late last week when a local man named Earl P Ford was found by passing state troopers masturbating furiously before an obscene birch tree.
Sheriff Arless Lee Wilton, one of the arresting officers, told me of the moment he discovered Mr Ford in mid stroke "We had just finished lunch and were driving back into town when my partner screeched to a halt, grabbed the radio and screamed 'What in the name of Jesus's holy donkey are doing son!' It was then that I saw Mr Ford about to splatter the filthiest looking tree I ever saw with his silver baby juice."

After both officers recovered from the shock they rushed over quickly and arrested the still shaking Mr ford "When we got him it was a fraction of a second too late, he had emitted his procreative gravy and was in the process of pulling up his dungarees. After we had cuffed him all he could say was that he couldn't help himself and slutty trees shouldn't ought to be allowed to tempt innocent god fearing men into acts of self defilement. I must admit after seeing the lascivious tree close up, old Earl has a point."

This should have been the end of the story, but because the tree had decided to put on its lewd display close to a local school, it was decided by outraged town officials that it must be cut down before the innocence of any passing children was unduly besmirched.

Before local authorities could get to the tree and put a stop to its filthy growth, a local Pastor saw the tree and immediately declared that it was not wooden pornography, but god given representation of a dying Christ on the cross sent by the lord to redeem local sinners.

The Pastor was so taken with the tree that he immediately chained himself to the trunk and began to loudly sing "Onward Christian soldiers" and preach to the bemused tree surgeons the city council had sent to remove the tree.
With things now reaching an impasse and tempers beginning to fray, It was the local librarian Mrs Eleanor Deutsch who suggested a compromise that has led to the peaceful resolution of Fort Jesus's filthy Birch/dying Jesus problem.
She came up with the brilliant solution of knitting a kaftan for the tree thus rendering it inoffensive and still capable of religious veneration.

So now whenever Mr Ford or for that matter any innocent school children pass by the offending tree all they will see is a silver birch clad in a modest woolen kaftan.