Hello forums I'm looking for a little help.

I purchased this 1990 350sdl knowing I need to replace the head gasket.
yea yea rodbender and such
I'm not afraid of the work nor is it my 1st rodeo doing a head gasket.
I just need a little guidance to help me along my journey.

My main question is head bolt removal and re installation. More specifically the order in witch I should proceed. I have gone thru the 606 guide on here.
https://www.pelicanparts.com/techarticles/Mercedes-W124/50-ENGINE-Head_Gasket_Replacement/50-ENGINE-Head_Gasket_Replacement.htm
But I'm personally convinced that 603 and 606 can't possibly have the same amount of head bolts and I don't think they would have the same sequence. Although I know they are very similar they cant possibly be the same.

Any guidance would be much appreciated. If anyone has a 603 guide that would be awesome. I've been looking with not much luck.

... Startek Model 126 Service manual, there is a pdf for cylinder head removal in the Engine manual section- looks like there are 26:

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1992 300SD 140.134 Sold

There’s also a sequence to loosen cam towers.

Sixto
98 E320s sedan and wagon
02 C320 wagon

Awesome thank you very much. My 1st 603. I've had 2 617A's. its got a 22 head on it so i hope I'm good on the possibility of cracks. I will update when I start work on it next week.

Want to do mine as well??

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Cam towers? What cam towers?

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CENSORED due to not family friendly words

IIRC, there are 7 bearings and the sprocket on the end of the cam that the TC rides on. The bearing caps must be loosened and tightened in a specific way, and the sprocket dealt with in a certain manner as well.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

I'm gonna paint marker and zip tie the **** out of the cam sprocket. I'll also make sure it always has tension on it. I had to deal with a fuel leak today. Figures the day I get it delivered the fuel line had enough rust. Just cut the line and jammed hose way down both sides. So far its fixed but not my end solution.

You perhaps live in a rustbelt. Pretty much similar to ours. Maybe not quite or nearly as bad. Before anything check out the front suspension mounts for excess rust.

We purchased the same chassis car for parts other than it had a gas engine. Superficially it looked decent with 175K miles.

It was really not repairable rustwise on closer examination. Many of the important front end mounting points and their general areas were very weak.

Odd there was not even a blemish topside. Interior was at least 90 percent as well. Maybe it was parked in grass at one time. Or just an exception.

We purchased it for parts as there was no way it could ever make the yearly inspection here. The owner told us this up front and the low price reflected the reality. Did not matter as we would have found it anyways. If he was trying to sell it as a serviceable vehicle. Plus I was interested in that gas model as a driver.

We can seriously repair many things but that car unfortunately would have been too much. Hopefully not an issue with yours and not likely. At the same time have a good look. Before spending money on it.

I hope and expect you will or already have found it solid. I use a sharp pointed tool as their undercoating can be so deceptive. Actually the coating they used at the factory was for noise reduction. Or thai appears to be the primary function it has performed. Most Mercedes might have done better with no factory coating of this nature in the rustbelts. It can keep the interface with the metal and coating damp enough. Plus enough oxygen penetrates to create the hidden corrosion under the coating. Actually the metal sweats with the frost and when it melts it is pretty much trapped in there.

As percentage of cost. It would take very little more to use metals that just will not rust out. It creates a lot more pollution to build replacement cars than for us to have cars with longer practical lifespans. I would even settle for cor ten steel. It can surface oxidize but it stops there. The best common use of it is in bridges now. If you see an unpainted bridge with a very light patina of rusting on it. That is core ten steel. Or I think that is what it is called.

I live in Salt using Upstate New York. The car was last registered in Vermont. And I have the original window sticker from New Hampshire. The underbody is better than the other 126's I've had not perfect but initial inspection looks good. I did see a spot today on the frame rail while I was crawling around. Its maybe a dime sized hole with a half dollar around it showing some rust. Not affecting anything yet. There are matching "repairs" on either side behind the rear tires above the bumper line. I use the quotes cause its really just poorly painted body filler over contaminated metal still. You can see the 1 spot in the pic I posted. At 1st before I got it I thought it was the reflection of my white impala. But today I got time to really look around it. There's a worrying spot by the rear window. Drivers side bottom corner. I know its letting straight up water in the trunk. The guy I got it from told me about it the day we towed it. And just to be fair hes a good guy and didn't know. He's had 10 5cyl diesels. This was his 1st 6cyl and 1st long body. He bought hoping to do exactly what I am now. He just doesn't have time with all the travel he does for work.

With all that said. My goals are. Make it really nice. The interior gets a 8/10 drivers seat is lightly torn...other than that just needs elbow grease. Not much work needed there. the out side is the work. Soooo. When i find a shop space to rent I can start cutting metal out and actually fixing it. Mind you. I am not a body guy. It will be my 1st time doing it. I watch enough youtube I feel like I can do it. I would like to put it on air bags. Put a fresh coat of Anthracite Grey Metallic. Tint the windows and maybe some elegant reserved wheels. And if I can do it I want to make fender skirts for it and put curb feelers on it. lol

If I find something very wrong and its not worth fixing I might turn it into a truck. Even then. I don't think I would with THIS long body. 2925 350sdl's made don't really want to kill a rare bird. Although I do want to make a truck out of a long body 1 day. I guess that's enough rambling for now.

Edit: I got it for 900 bucks. So either way its a deal.

I see no problem. I was just concerned it may have been your first older Mercedes. Plus I still believe we all have rose colored glasses the first time around to some extent with these cars. I thought you were a new member as well had a bearing.

As for your cost I seriously suspect you could recover it by selling the number 22 head alone almost anytime. I also suspect cracks in the number 22 head would be rare.

You do want to follow the recommended way of removing and reinstalling the cam. Basically it amounts to more evenly removing the pressure of the valve springs from it both on removal and re installation. If you do remove what amounts to the lifters for the cam. Number them as they have to service the same cam lobes without fail. Also you might want to clean them properly and test them. All it takes is access to a drill press. The method is pretty simple. Internally cleaning and de gumming them is usually worth the effort.

The head gasket job should go smooth enough. I think you know it is better to line up the tdc of the harmonic balancer and the cams timing marks before pulling the head. Very hard if not almost impossible to go wrong then.

I am not quite sure of just how people get this job completed with the cam on the wrong stroke. Just suspect by not doing that first helps to avoid it a lot. Tying the cam gear to the chain is also helpful but not really required.

It was at least fifty years ago I dealt with the chain issue the first time. On a gas fintail model. Actually I would still like to own another good one with the manual gearshift near the steering wheel. The build quality was fantastic. This is not going to happen though in reality.

I do remember well seeing your model pull away from a service station when they were new. The power that engine had was impressive as the guy accelerated up the long ramp to get back on the freeway. Actually initially I did not think it was even a diesel until I saw the trunk label. It was in the area of the north eastern states. I think it was black or a darker color. Age gives your mind the ability to recover the past easy. At the same time you question just where did you put that tool yesterday. Although I still risk going to town without an extensive written list and not forgetting anything. Strange that I would forget something when younger on more than one occasion per month.

A strange thought occurred that statistically with the low production numbers. There is a very small chance it was the same car. I live in eastern Canada and was endlessly going down and back through the area the car came from in those days. Not that it matters one way or another.

This post was backtracking a little as I did not realize that you had owned several of these general type of cars. You have had the past experience with them I now know. The rear window issue is not structural just a pain to repair properly.

As for me I am just an old goat that is still active in many things for some reason. I just finished the final touches on re roofing half the second floor roof today. I started to strip it with a four day window of decent weather for cast. Well over a week ago.

Just as I threw almost the last of the old shingles off. The wife pops out and mentions the for cast has changed. To heavy rain tonite. So there I am as it is getting really dark getting the ice and water shield on plus the underlay secured well enough to not blow off. It has rained to some extent every day since as well or the winds where too high for me to work comforatably. I think we may have even got a little of the residue from that really bad southern hurricane as well. I was going to pull the staging down tomorrow. Cancelled because of even more rain again for the next two days.

Oh, I also have developed the ability to ramble on. Plus welcome to the site.

I was born with the gift of gab also. Both sides of my tree gab. The spot by the rear window I will have to do something before wither fully sets in. I wish my situation allowed me to just store it over winter. But...I recently got out of a long relationship (2.5 years, engaged the whole 9) where in the end it turns out i was just a paycheck. So here i am 32 years old. In my mothers 1 bedroom apartment. The ex took the van we had. And I frankly don't want it. She made sure she had it with 0 income to pay for it and beat the snot out of it.

So step 1 was get a vehicle. And I absolutely love the 126's. I got rid of my last 1 so she could drive around for a job that she quit in 3 weeks. Things with her were never great and I was stupid to have hung around as long as I did.

Step 2 is to find a garage I can live in. I really don't need an apartment. I want to start making Youtube videos anyway. Because at 32 it's time for me to do what I want to do. Not to dive into it but I've had a rough life. And I'm beginning to feel free. not socially because I still have to work. But who knows where life will take me next. Experience is the currency of life the more you have the richer you are.

I'll get a bunch of pictures of the car today. Haven't had a chance. I work nights so daylight is hard to come by. Ttyl folks.

well this thread derailed quickly..
from head gasket to rust.

anyways the only thing that is different with these motors vs other are the steps you need to do to mess with the chain. everything else is normal. if its a critical bolt like head or cam tower crack them all loose in the reverse order of tightening before you remove them.

to pull the head you need to pull a chain guide which is held in with pressed in pins. i rigged up a puller using small sized hardware and a socket at the junkyard yesterday. now i have a $100 17 head lol.

no need to remove cam just to change head gasket.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

I never did a 603 type engines head removal. I just assumed the tower bolts also supported the head. Assumptions can be dangerous. Anyways I would not go in that far without removing and internally cleaning plus testing the lifters.

Just replacing those that were testing bad. If any. Also as usual if they had been changed before. Usually the current owner does not get the information to know when this occurred.

As for a rear window area patch of a temporary nature. Perhaps a six mil piece of plastic could be siliconed over the area. The plastic has poor ultra violet resistance. It has never been a selling feature that silicone has a massive amount of uv resistance. It does though.

The only problem is on removal you have to get it all. Nothing I can think of will bond with the residue. There may be another adhesive caulk that is better for something like this. I just do not know what it is.

For us that live in rustbelt areas. The amount of rust established in these series of cars is a really important factor. Easy to repair mechanical issues in comparison. Once corrosion moves past a certain point. It either is not practical to deal with or just not worth the effort.

We did see many cars with far too much of the metal as just iron oxide well on its way to reverting back to nature. Supported on two sides by that insidious coating.

How bad can it be? A neighbor dropped by to use our stretcher and shrinking tools to fabricate a patch for his station wagons rear roof on a ford product. He asked us to have a look at his rear shock towers. A quick inspection was the whole floor was still present but so seriously weakened with rust it was not practical to do anything. You could push a screwdriver through anywhere easily.

His wife was killed in the car a few weeks later when the car folded up. When another car hit it. I really believe the structural weakness of the far too rusted unibody construction was a factor in her death. .

Since then the mandatory yearly initially but now every two year safety checks. Have proven to have some value in stopping this. Some places still give out bogus safety passes. Generally letting minor things pass. They will no longer certify a car with signifigant rust though. There is just no way they could claim in court the rust occurred since the last inspection and might fail their liability issues. Plus have their inspection privliges revoked. A rust hole through the metal anywhere will disqualify a car here.