240D Head gasket... or ...

[Fisherman]

Boy am I glad I found this forum. Just reading through the posts it looks like a great bunch of people.

My issue:
I just acquired a very nice looking little 240D which by all accounts runs well. However, yesterday after the wife parked the car I found antifreeze under it. Upon closer inspection it appears to be coming from just below and behind the number 4 exhaust port. My guess is head gasket. Can anyone confirm based on their experience.
Now to the meat:
1. How dificult is it to repair (I am pretty good with wrenches)?
2. If professionally repaired anyone have a ballpark cost that I should expect?
3. Are there any good manuals for a 1975 240D and if so from whom?
4. Anyone want to drop by and fix it for me...;-)

Thanks in advance for your help.

I understand your excitement about finding MShop. I still remember how happy I was over two years ago when I came across it. Warning, it can be addictive and cold Turkey withdrawal is not a pretty sight. Welcome!

1. The 240D is a joy to work on. The five cylinder is basically the same engine, but much more difficult to get those wrenches onto it. There are special tools you must make or buy along the way. For a head gasket replacement you will need to bend two cheap 14MM open end wrenches for the valve adjustment. The set is about $50 or so to buy, but you can heat and bend them up yourself. You will have to fashion a puller for some pins that hold in various timing chain tensioner rails, you only need a bolt, some washers and a big nut to make this one.

2. I really don't know, I would guess $600 for the head gasket alone, but if you have the head off, you should go ahead and do a valve job including new valve guides. To have this done would surely be over $1,000 total.

3. The Haynse manual should work well for this older car. It works well for the 123 series ('77 to '85.)

4. Sorry, I'm off to Phoenix week after next, then Europe two weeks later, I won't be going your direction for quite a while. Maybe after your finished though......

This is unusual on a 240D. They are an iron block, iron head motor and just don't blow head gaskets. In your case though, you probably don't know the true history of the car. Maybe it was recently taken apart and something was not done right. Are you absolutely sure that the leak is at the head to block seam.

Best of luck with it,

[engatwork]

You sure it isn't coming from one of the heater hoses on the firewall?
These are excellent diy'er type engines.
Look on ebay for an engine manual to come along. The Haynes manual will provide basic information but the engine manual is by far the best manual to have.

[Fisherman]

Thanks for the input. Anyone buy the 240D CD from Mercedes benz? Are they worth it for a hundred bucks?

[Fisherman]

Is it possible that this could be caused by a bad exhaust manifold gasket? The leak appears to extend all the way from the back left corner of teh motor to just in front of the number 4 exhaust port. It seems to extend up to the manifold but is hard to tell what with the lines in the way.

[DJChillfit]

Heya Fisherman, welcome to the forum. Where in Oregon are you located? I'm in Eugene and am always interested in knowing the local Benz-heads.

Simon
78 280E 130,000 mi.

I have rebuilt a few 123 diesels and have never owned any manual except the Haynes.

I am puzzled by your leak. It's not terribly difficult to remove the manifolds. I wonder if you were to pull them if you could see more about where the leak may be coming from. Again I will be surprised if it is the head gasket, but just because it is uncommon does not mean that it can't happen.

Best of luck,

[Fisherman]

Hey Chillfit,
Used to be from "BlueGene" (born and raised)but now reside in Bend out of the rain...;-)

Got a second opinion on the head gasket and it appears to be a water leak with no loss of compression, yet!
I think I'll have to tear it down and check out the problem after I get my van fixed. You know the one that ran into the deer at 75 mph, ouch!

I was intending on using the Haynes manual but since my car is a 1975 on the 115 body I am concerned that it will not help me with my other projects i.e. wiper problems, heater/air conditioner issues, etc...

My apologies to those that earlier replied to one of my posts concerning the instrument guage cluster removal. I slipped and said I had the 123 body, oops...

Anyway, looks like a great project car and Mommy loves driving it. She's even talking now about giving up her Grand Wagoneer with the 401 motor for this one. Man that could save some money eh?

[P.E.Haiges]

Fisherman,

Have a Frabo test or pressure test the cooling system before you pull the head. This might isolate the leak and save a lot of work.

It can't be a manifold gasket because even if the manifold was removed completely, it would not cause a coolant leak.

P E H

[Fisherman]

P.E.,
I suspected this but thought I better get a second opinion having never owned an MBZ. Some manufacturers do the strangest things.
Confirmed Head Gasket, now is just a matter of getting the time to tear into it.

[P.E.Haiges]

Fisherman,

Here's a hint: Put wires thru the timing chain so it doesn't drop into the engine.

Also after engine is reassembeled, turn the engine by hand 2 revolutions by putting a 27mm socket wrench on the crank shaft bolt. This will eliminate breaking anything when cranking with the starter if the cam timing is off.

P E H

[Fisherman]

Great hints!
Thanks!

[P.E.Haiges]

Fisherman,

I suggest you set the engine to 0 degrees with the cam timing marks lined up before you remove the timing chain (TC) from the cam sprocket. Don't turn the engine until you replace the timing chain on the cam sprocket. This way you shouldn't lose the timing of the injection pump or cam.

When you lift the head a few inches, have another person put more wires thru the TC so you can pass the TC thru the head without losing it. It is best if you keep the chain taught until you can wire it in place.

I remember one time I didn't have any help so I cut rubber bands from an inner tube and wired them between the ceiling and the TC. This kept the TC tight until I could lift the head and put some spacers between the head and the block so I could wire the TC so it wouldn't fall into the block. It may sound strange and you won't find it in the repair manual but it worked for me.

P E H