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Discussion Starter #1
Hi everyone
I own a 1976 Mercedes 250c. It has the 2.8ltr engine and it needs the head gasket replaced.
I am about to tackle the job myself but before I start I thought I would ask around and see if anyone has had any experience replacing the gasket.
I have searched the forum but can't find anything related to the topic.
It would be fantastic if anyone could help me out with any advice or techniques that will make the replacement go smoothly.

Thanks
Callum
 

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'72 250C, '74 280C, '85 500SEL, '81 300CD.
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Replacing the head gasket on the M110 is not for the faint of heart. What is your mechanical expertise? I would rate this as a 8 on a 1-10 scale. Lots and lots of fiddly stuff is involved. The cylinder head is actually 2 pieces. The cam assembly and the head itself. Figure on a full 8 - 12 hours of work if all goes well.

I would spread it out over a couple of weekends. Pull the head the first weekend, send it off to the machine shop, and spend a couple of hours during the week cleaning the deck surface, cam tower, manifolds' mating surfaces, engine block and whatever else.

Now would be a good time to replace the short hose between the thermostat housing and the lower coolant port and the heater hoses.
 

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Discussion Starter #3
Hi there
I have removed the rocker cover, manifold and all the head bolts but I am having trouble removing the cam chain. Is there a simple procedure to separate it from the head? I have loosened the top sprocket that is connected to the cam in the hope there would be enough give in the chain to be able to slide the sprocket off and remove the chain but there is not. Can you point me in the right direction? This is the first time I have worked on these engines so any help would be appreciated.
Thanks
Callum
 

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It totally depends on your mechanical skills--A Haynes manual will help but it is not easy. If you do it be sure to measure the length of your head bolts and if you have oil in the coolant all hoses must be replaced
 

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1965 220S, 1999 Volvo V70 (wagon), 2006 Ford Crown Vic Police Interceptor, 72 350SL 4 Speed
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Replace the collant bypass hose while the head is off.

You really need a service manual for this.

Mercedes-Benz Model 116

select either the 280S or 280SE for carb or FI. The engine section is the portion you want and the instructions will be in there for pulling the head.
 

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'72 250C, '74 280C, '85 500SEL, '81 300CD.
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Depending on the condition of your engine mounts there is a way to remove the sprocket without breaking the chain.

At the rear of the right side cam tower (exhaust side) there is a triangular plate. It is held with 3 bolts. Remove the bolts and the plate. The cam will slide back and allow the gear to come free.

The odds are you will need to break the chain which is faster anyway.
 

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Hi there
I have removed the rocker cover, manifold and all the head bolts but I am having trouble removing the cam chain. Is there a simple procedure to separate it from the head? I have loosened the top sprocket that is connected to the cam in the hope there would be enough give in the chain to be able to slide the sprocket off and remove the chain but there is not. Can you point me in the right direction? This is the first time I have worked on these engines so any help would be appreciated.
Thanks
Callum

You need to remove the master link in the chain. It is very hard to find because it has 2 very small "c" clips at the back of the chain that hold it on. You need to turn the engine slowly to locate the "c" clips. Be very careful when removing the "c" clips because they are small and if they get away from you, you will never find them.
 

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1967 250 SL, 1965 300SE lang
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I own a 1976 Mercedes 250c. It has the 2.8ltr engine and it needs the head gasket replaced.
...1976... are you sure you don't mean a 280 C? A 250 C has a 2.8 liter M130 engine, a 280 C would have a twin-cam 2.8 liter M110 engine I think...
 

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You need to remove the master link in the chain. It is very hard to find because it has 2 very small "c" clips at the back of the chain that hold it on. You need to turn the engine slowly to locate the "c" clips. Be very careful when removing the "c" clips because they are small and if they get away from you, you will never find them.
That assumes the chain has been replaced at least once. The 6 cyl's have a shorter chain that the 8 cyls and don't need to be replaced as often.
 

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1966 MB 200; Porsche 914 (6); Porsche 914 (Chev 350); 36 ford
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Look for my thread on my 200. It's about the same procedure.

I have pictures and details about when I replaced my head gasket. As someone said. this is a harder procedure than most activities.

1. First find the C link as someone mentioned. Be careful and not drop the link and clips into the motor. I usually set the engine to TDC, then remove the link. I also mark the distributor and make sure it's TDC by taking the valve cover off and making sure the #1 valves are closed. To prevent something falling into the engine, I stuff rags around the area, so if the link falls, it just lands on the rags.

2. Get some wire, and do not let the chain drop into the engine. This should not be much a problem if it does, but its a hassle.

3. Then you can start to take the engine apart. You will need to remove the chain guides. (Again, best look at my thread about it.)

4. Much more disassemble and best to look at the manual. This should get you started and then you can ask more questions.

5. Inspect the motor. If the coolant has not been replaced at regular intervals, there could be damage to the motor.

6. Before you spend money on the head, I would have it pressure checked. No sense spending money on a bad head.

Usual caveats. I am not a professional mechanic, and these comments are my opinion. USe are your own risk.

Hope this is of some help. I got lots of good help, as I was doing mine.

Link to my thread: http://www.benzworld.org/forums/vintage-mercedes-benz/1541829-w110-heckflosse-project-1966-200-a.html


-- brett
 

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Discussion Starter #12
Hi again
I've had another go at removing the cam chain tonight. I still have had no luck with it. We have checked over every inch of the chain carefully and cannot locate any 'c' clips where the chain can be seperated. Instead of breaking the chain, is there a technique to release pressure in the chain tensioner which will allow the chain to slacken and lift the chain off the top sprocket?
Thanks once again
Callum
 

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Discussion Starter #13
Also, Hi Brett, I have looked through your thread that you provided the link to and I can't see anything that refers to the specific issue i'm having. The info was still very useful though and will help me later on.
Thanks
 

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1966 MB 200; Porsche 914 (6); Porsche 914 (Chev 350); 36 ford
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Don't do that. You could damage the cam or the sprocket.

I will take a picture tomorrow and post what it looks like.

-- brett
 

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I think most of my progress was on a differnt forum. :)

I will go back and add some more details.

-- brett
 

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Hi again
I've had another go at removing the cam chain tonight. I still have had no luck with it. We have checked over every inch of the chain carefully and cannot locate any 'c' clips where the chain can be seperated. Instead of breaking the chain, is there a technique to release pressure in the chain tensioner which will allow the chain to slacken and lift the chain off the top sprocket?
Thanks once again
Callum
They are there and are very small. It took me a while to locate the master link. You cannot remove the chain without removing the master link. Unless you want to break something.
Like I said the "C" clips are on the back side of the chain and are very small. Here is a pic of what you are looking for and again they are very small
 

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2005 C350, 2002 ML270CDI, 1969 230S, previously 2002 A160, 1985 380SEC ivory, 1983 380SEC grey
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Hi Murph101
One issue you should be wary of is the state of the aluminium cylinder head. I bought a 1968 230 Automatic with a "blown head gasket" for only $500. On inspection the reconditioners more or less refused to do anyhting to it because it had cracked and been welded. The welding softened the aluminium and it had eroded badly between the cylinders.
Several replacement heads from auto wreckers were also rejected, and I eventually found a guy in Adelaide who had acquired a few Euro engines which had been imported many years ago, and in which proper coolant had been used. A cylinder head from one of those was all good, and so my mechanic fitted that, and the car has been going well ever since. I keep it in the country and go for a drive about once a month at speeds of 60 -70 -80 miles an hour. It started to overheat but I got the radiator flushed and it has been OK since.
The moral of the story is that, in Australia in the 1960s and 70s, they used water instead of coolant and practically every engine /cyliner head from that era is corroded.
So when you get it off (and I can't help you with the cam shaft issue) get it checked VERY carefully.
all the best
David
 

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1966 MB 200; Porsche 914 (6); Porsche 914 (Chev 350); 36 ford
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Took some pictures.

Here's the chain and the link. You can see it is a slightly different color, and you can see the c-clips that need to be removed.

In the second picture, you can see the pins in the head that have to be removed after you get the chain apart. The factory tool is a small slide hammer. I used a bolt, an oversized socket and some washers to pull the pin out.

Finally, I agree with David. That is what happened to my head. My cousin who was driving the car last, never changed the coolant, and there was extensive corrosion. Head failed pressure check, and machine shop would not recondition the head.

Hope this helps.

-- brett
 

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you do not need to take the chain out. Once you have loosened the tensioners as in picture 2 the chain should have some play. You can tap out the sprocket, just make sure the chain does not fall into the block. If Im not mistaken, the haynes manuals have a step by step on removing the head. I have changed the head head on the same engine, if you have all your tools in order , it shouldnt take more than 2 hours to take off. good luck
 

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just confirmed with a buddy. The haynes manual does have step by step instructions and he told me they are very clear and simple. By the way, I had the head welded in spots and the welds did not hold up. had to buy another head from chuck at Allbenz. good luck once again
jimmy
 
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