#14 and #22 head - PeachParts Mercedes-Benz Forum

psaboic · #1 09-30-2013, 11:44 AM

I tried searching but everything but what I am looking for seems to come up. I know it is fairly common knowledge, but could someone explain the issues about the #14 and #22 cylinder heads to me. Basically, what is the problem that occurs, what engine these heads were used on and what cars used the engine that had the issue.

Sorry for asking what is probably a dumb question I should know the answer to, but my curiousity has finally made me ask!

Glenn

vstech · #2 09-30-2013, 11:59 AM

#14 heads were thin castings used on 86-88 Diesel 603's the problem occurs when the cooling system is not kept up, and something fails. the heads cannot tolerate ANY cooling problems, and they crack when a cooling system problem occurs.

#22 is the newest thick casting MB made for the 603 engine. it's supposedly immune to these problems, but keeping the cooling system happy is still wise.

whunter · #3 09-30-2013, 12:04 PM

This should answer all of your questions + give more data than you ever wanted to know about the topic.

http://www.peachparts.com/shopforum/diy-links-parts-category/173492-350sdl-om603-mechanical-diesel-injection-links.html

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winmutt · #4 09-30-2013, 12:35 PM

I often wonder how many people misdiagnose #14 failure instead of the far more common hg failure.

whunter · #5 09-30-2013, 12:51 PM

Quote:

Originally Posted by winmutt

I often wonder how many people misdiagnose #14 failure instead of the far more common hg failure.

The diagnosis is never complete until the cylinder head has been removed for inspection and testing.

I agree that some good OM603 cylinder heads/engines have been condemned, when it was only a bad cylinder head gasket.

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tjts1 · #6 09-30-2013, 02:36 PM

Quote:

Originally Posted by winmutt

I often wonder how many people misdiagnose #14 failure instead of the far more common hg failure.

My #14 head cooling system holds pressure long after the engine has cooled off yet consumes no coolant and very little oil. At first I thought it was a bad but a year later it still runs perfectly smooth. I'm guessing bad HG. I have a complete #17 head just in case. I don't see any reason to tear it apart at this point.

ah-kay · #7 09-30-2013, 03:04 PM

Quote:

Originally Posted by tjts1

My #14 head cooling system holds pressure long after the engine has cooled off yet consumes no coolant and very little oil. At first I thought it was a bad but a year later it still runs perfectly smooth. I'm guessing bad HG. I have a complete #17 head just in case. I don't see any reason to tear it apart at this point.

If the hose is rock hard after engine cools off then the HG is suspect. I had the same problem before. I changed the radiator cap to lesser pressure, 14psi, and it did not use any coolant. It does not mean the HG is OK. Try to go Death Valley in summer and you will find out the HG problem real quick, BTDT. I jury rigged the aux fan to come on at all time to get home. I changed out the HG and hose is soft when engine is cold. The hose should NOT be hard or pressurized when engine is cold.

I really do not believe #14 is as bad as some members believe. I took 2 #14 heads off and I always see hairline cracks near the valves. I think it is kind of normal for a 20+ years head and I do not believe anything is breached. I cleaned them all up, re-installed the head and the cars all run as new. It is nice to have a #22 head but I would not specifically look for one. #14 heads served me fine with 351K and 305K miles respectively.

whunter · #8 09-30-2013, 03:18 PM

Quote:

Originally Posted by tjts1

My #14 head cooling system holds pressure long after the engine has cooled off yet consumes no coolant and very little oil. At first I thought it was a bad but a year later it still runs perfectly smooth. I'm guessing bad HG. I have a complete #17 head just in case. I don't see any reason to tear it apart at this point.

If the engine hydro-locks = bent piston rods..

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