Always stick to the basics, no short cuts....!!!!!

[Ccmano]

I was somewhat hesitant to post this, because, as you will see, it is really embarrassing for me. My hope is that by posting this it will save someone else from making the same mistake I have recently made.

Many years ago when I was a trainee at Mercedes-Benz I worked with a crusty old German master technician named Herrman. Herrman would always drill into us that when diagnosing a technical issue to always stick to the prescribed basic diagnostic procedures. Never ever take a short cut even if you think you know what the problem is. I saw this play out countless times when Herrman was called in to fix a problem that no one else could. He would always quiz the technicians to find out if they went through all the diagnostic steps to find the issue. Invariably short cuts were taken which resulted faulty diagnosis and unresolved problems. He would cuss them out from top to bottom. He was the best technician I ever worked with.

Well... now it is me that is guilty taking the short cut. You may remember my recent thread on my high mile Z that suddenly started burning significant oil. I ran several tests and checked “all” the systems. I came to the conclusion that at least one of the oil rings had given up and that was the cause. I decided to replace the engine with low mile 91 engine that I recently purchased. Given the 180k miles on the current motor I thought this was reasonable.

I am now in the process of tearing down the old engine in preparation for pulling it out of the car. Today I pulled everything off the top of the motor including of course the plenum and injector housings. To my uncomfortable surprise I found that the injector housing to head gaskets were stone hard and the IH bolts were loose. Upon closer examination there were significant signs that oil was being sucked from the breather passages directly into the cylinder heads. The gaskets were literally soaked with oil. It was obvious where the oil was coming from.



I even recall thinking that the IH gaskets could be a possibility. I dismissed the thought because I saw no sepage into the valley and frankly I had never heard of such a thing on our engines. And of course I had convinced myself that the oil rings were the issue. Had I followed through to properly diagnose the issue I could have saved myself an engine replacement, at least for the time being. Taking a short cut bit me in the a$$.

All is not lost, my high mile Z will now have a virtually new drive train (trans is brand new and the diff has been rebuilt) with some additional goodies like top end porting, headers and a fresh finish on everything. The old engine which was surprisingly strong with great compression (and apparently no oil ring issues) and oil pressure will be parted out to recover some of the costs.

Herrman was always right. Stick to the basics and never ever take short cuts when dealing with technical issues. I hope this will help someone else from going down the same rabbit hole.
H