I was digging around the WEB this evening looking for solution(s) to an issue I'm purusing with one of my Asian vehicles when I stumbled across a site that featured tech tips from professionals. One that I found particularly interesting, especially for MB diyers with M103/M104 motors was a way to determine if a head gasket is blown or leaking. The text from this article has been cut-n-pasted below. Maybe this approach will be of benefit to someone here in the near future.

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Fill It Up: Being fooled by chemical testing/infrared testing of the cooling system for head gasket failure(s), I stumbled on a better method, which is much faster and more accurate, too. Next time, try this:
1. Remove all the spark plugs from the engine.
2. Fill the cooling system right to the rim of the radiator neck.
3. Disable the ignition system.
4. Insert one spark plug in a cylinder and then crank the engine for five to 10 seconds, while watching the radiator level. (A remote starter comes in real handy here.)
5. Repeat step 4 above for all cylinders.
The idea behind this is simple: This uses the engine’s compression to pressurize the combustion chamber and force this pressure past any potential head gasket/cylinder head leakage into the cooling system. Should there be a leak, the level in the radiator will overflow. The reason all other spark plugs are left out is to allow the starter to spin the engine faster, without shaking so much and helps to identify which cylinder is the culprit. Why not let the 150 to 200 psi compression do the testing? Now, 13 to 15 psi in the radiator to test it just doesn’t seem up to the job anymore, does it?
Brad Petersen, Owner, ASE L1 Master Technician
Petersen Automotive, Escondido, CA

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

what website did you get this from?

thx,
emmy

Simple enough, and seems like it would work. But with 12 cylinders, it would take a while.

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I do not specifically recall the exact name of the site. It was an ASA(automotive service association) site. There are many on the WEB. Inside of it was a "Tech Tips" area. That's where the authors tidbit was posted.

Look above at his name -> Brad Petersen - Petersen Automotive - Escondido Automotive. I searched on "Petersen Automotive" under Google - came up with the following:

http://www.ourautoshop.com/

If you can't find it, perhaps you can call/email his shop for the URL.

The "Tech Tips" area was full of very interesting information.

If I come across it again, I'll post the URL in this thread.

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Found the link:

http://www.motorage.com/motorage/article/articleDetail.jsp?id=73721

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Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Twice as long as it would take me, except I have another 6 cyl car and a 5 cyl car, so I'd be behind in the long run.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

The Peterson Automotive method can detect only one failure mode - chamber to coolant. There are other ways a head gasket can fail - coolant to oil, oil to coolant, coolant to chamber, chamber to chamber, and oil to the outside of the engine. It is the last failure mode that M104 engines commonly experience.

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95 E320 Cabriolet, 159K

A simpler method to detect a chamber to coolant leak is simply feel the top radiator hose upon cold startup. If you have pressure in the cooling system right away, you have a leak. I've had two cars do this (a Jap and the race car), very obvious what needs done at that point.

The other failure modes can be tested by visually checking the oil, coolant, and outside of the engine. All of this assumes a fairly substantial leak however.

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Lenny

There are only three sports: bullfighting, motor racing and mountaineering; all the rest are merely games. --Ernest Hemingway

'10 GL550/'04 BMW 545/'99 BMW 323/'98 ML320/'87 VW GTI (race)

And on a 103 the usually "failure mode" is oil into the coolant.

Gilly

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