Overheating-cracked block?
 

I was hoping I could get a second opinion. My 1983 300D overheated. A coworker who is good with cars said he suspected it had a cracked block, so I stopped driving it. The car has been sitting for over a year without being started--until today.

There's a good chance I may be moving, and I've been reluctantly thinking about selling the car. Today, I put a battery in it and it started up immediately.

I noticed there was no antifreeze in the reservoir so I added it while the car was shut off. I noticed that the reservoir was not filling, so I started looking around for a leak. Turns out there was a steady, small stream coming from underneath the car toward the front middle. I got under the car and looked and followed the leak upward. Pictures are attached.

I'm wondering if this is what a cracked block looks like?? Do I need to accept the car's untimely death and move on?

Answer
 

That is a bad cylinder head gasket.


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Thanks. Can you tell me roughly how much it would cost to repair/replace?

Answer
 

If the head is OK, and you DIY
1983 Mercedes-Benz 300D Sedan - Cylinder Head & Valvetrain - Page 1
+ oil change and antifreeze.

If you take it to a shop $500.00 - $3,000.00 USD.

If the head is cracked ???

http://www.peachparts.com/shopforum/diesel-discussion/285883-om617-head-gasket-failure-pictures.html

http://www.peachparts.com/shopforum/diesel-discussion/325016-1980-240d-cracked-cylinder-head-cavitation-damage.html

http://www.peachparts.com/shopforum/general-information/272132-cavitation.html

http://www.peachparts.com/shopforum/diesel-discussion/155113-leaky-head-gasket.html#post1184752

1985 300TD head gasket repair
http://www.peachparts.com/shopforum/diesel-discussion/325433-1985-300td-head-gasket-repair.html

http://www.peachparts.com/shopforum/diesel-discussion/306995-om617-intake-exhaust-valve-guide-id-specification.html

http://www.peachparts.com/shopforum/diesel-discussion/272804-need-definitive-om617-compression-test-procedure.html

http://www.peachparts.com/shopforum/general-information/239902-home-made-special-tools-where-members-can-share-how-they-made-special-tools.html


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At different websites, I'm seeing about 10 hours labor time to replace a head gasket. Does that sound reasonable? I know a very reputable independent Mercedes mechanic who charges $60/hour. Thanks again.

sounds about right. I'd prolly check the valves while its off though and do a grind and replace any weak springs and or worn valves.

I don't want to question Roy much but I thought it looked like a leaky freeze plug. It also looks like a rubber squeeze it freeze plug replacement.

also, does it not look like theres a crack directly underneath the glow plug? Or is it just the photo??

When the Head is removed besides have it checked to see if it is still Flat they should do a pressure test to see if it leaks anywhere.

There is a few ways to fix external leaks but if you need to pay someone to do that it is not worth the trouble. Also someone doing that type of repair needs to be more skilled than the average Mechanic.

Also, when an Engine overheats it is more common for the Head to warp and maybe crack or for the Head gasket to go.
Once in a while Blocks crack but if it is due to overheating the often Pistons Skirts will also be all chewed up and the Cylinder walls will not look so good.

It is more common for a Block to leak due to some casting flaw or porosity.

The Block can also be Pressure tested if they have a Plate or Plates made for that.

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I enlarged part of the pic.

Yes, it is a rubber freeze plug replacement. That was put there after the car overheated and we looked and saw that a freeze plug was missing.

I don't know anything about cars, so please forgive me if I accidentally omit something important. I like visiting these forums because I learn quite a lot!

I was looking at the first Pic and I was thinking what if there was a Freeze/Core Plug Leaking?
Before you tell your Mechanic to remove the Head I would let Him pressurize the Coolant System and see if He can find exactly what is leaking.

Answer
 

It would be extremely unusual to have a crack there on the OM617.


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Stop
 

More data needed.

What state are you in ?


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Western North Carolina
 

Western North Carolina.

Answer
 

Western North Carolina = snow and below freezing temperature.

They are called freeze plugs because; If the coolant freezes solid (theoretically) they break, instead of the cylinder head or engine block.

Now I need to change diagnosis.
The engine is dead, head broken, and serious risk of a cracked block.

I would contact "vstech", he may have a good spare engine and is near Charlotte, NC.


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Next course of action.....
 

Would it be worthwhile to tow it in and see if the block is cracked and go from there? I suppose worst case scenario is that the block is cracked and the mechanic might want to buy the car for body parts.

I have a 1985 300D with a good engine. If I were to entertain the idea of an engine swap, is that something most mechanics could do or only a good Merc mechanic?

I don't think the Mercedes mechanic I like is interested in dropping an engine in the car; he quoted me a ridiculously high price.

Yes
 

IMO it is worth a diagnosis of the engine block. Really hope it is not cracked.

Most mechanics can do the engine swap.

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Engine swap if the engines are the same type, is pretty brainless, you can do yourself in your driveway, it is like changing the wheel... remove bolts and connections, remove, put back, put back bolts and connections... only gets complicated if you want to do other things, like install 90's SL 500 V8 into 240 D of 70's :)

Thanks.
 

This is very helpful. Thank you. I really hope it isn't the block, either. This engine had a whole lot of get up and go before all this happened and it was such a pleasure to drive. I'm having a hard time letting go of the car. Someone expressed interest in buying it as a parts car for $500, but I just could not bring myself to do it.

The '85 does not have nearly same pep and the body is quite a bit bigger, so I'm not as fond of it. We'll have to see what unfolds, I suppose....

Engine swaps.
 

I truly admire people who can do this. I can't. I don't have that kind of mechanical know how.

I read in another thread that I'd need to be careful to keep the turbo and the injection pump from my '83 since the '85 is different. Does that sound right?

Diagnosis pending.
 

The car has been towed to the shop. I'll let you all know what happens. Thanks, everyone, for your comments.

Typically, the '83 and '85 300D's have a different rear differential with the '85's being taller. This results in a quicker lower speeds on the '83 and a lower revving higher sppeds on the '85. The '85 probably gets better fuel mileage if everything else is equal.

If the '85 is bigger, then its probably a 300SD?

It might be different but if it works fine on the 85, I would just use it all, since you take the engine out and put it in without having to take off the turbo and IP... so why work harder for nothing? Definitely keep the old ones in case you need to replace them later

But I'd pay attention to the '85, if it is junk, then fine, but if it is a nice car... it might be better to find a good engine in a wreck or junk to take engine from.

Well, after all of that......
 

The verdict is that the hose that meets the cylinder head gasket needed replacing!!! He said the engine is in good shape.

well that makes for a happy (and cheap) ending

Yes! I'm happy for the OP. I'm also really happy to know that changing an engine out is as easy as changing a wheel! :bounce: Volker, i need a neighbor like you.