Dieselvolk, My '87 300TD has a valve tick that I want to fix. I'd appreciate thoughts and input on what the problem is and how to fix it.
History: I've only used Mobil 1 oil since purchasing the car about 50k miles ago, when it had about 284k miles It now has 334k miles. About 3 years ago (~20k miles ago) the tick developed after a 450 mile travel day, during which the car ran very hot but did not overheat, due to a long stop-n-go traffic jam on the freeway. Car had increased oil consumption during the trip (used about 1 qt in 500 miles, normally only uses 1 qt per 2000 miles), and the noise began the next morning upon first start. After fussing over the noise for a few days but not really doing anything other than add oil and determine that the noise originates from either the #2 or #3 cylinder valves in the head, the noise largely went away on its own. After that episode, the noise would occasionally come back if the car was exposed to cold weather (i.e. around freezing or lower), but once it was driven the noise would reduce to the point that I really had to listen hard, generally with the hood up, to see if it was still ticking. I tried testing the lifters (hydraulic valve clearance compensating elements) in accordance with the book, and they passed, but that was at a time when the lifter tick noise was reduced. The current engine oil is now 10k miles old. It is Mobil 1 5w-40, and the 5k oil analysis showed only 0.4% soot. I sent in the 10k sample last week, should have results shortly. All previous oil samples were negative for glycol (coolant) and wear metals are pretty normal in my opinion. This past January the noise came back with a vengeance after I drove the car to Baltimore, and then car sat in a freezing parking lot for a couple of weeks. I drove the car home, and since then I've only driven it a few times, but the noise is almost constant. Now it will sometimes be reduced when the engine is cold, but once the car warms up it comes right back. So here's my plan. 1) Warm up the engine and then pull the valve cover and test the lifters again using the book method. If any fail the test, replace them. Inspect the camshaft lobes for wear. 2) Change the oil. 3) Replace the lifters for #2 and #3 on principle (they're noisy). 4) Pull the head and replace the head gasket, assuming a failure at the oil passage between #1 cylinder and timing chain case, allowing oil to flow into the timing chain area and back the sump, which reduces the oil pressure to the head and causes the noise. I like this option least, because I fear finding cracks in the (number 14) head and I'm worried that if I put a cracked head back on, the cracks will worsen and I'll start burning coolant or mixing oil and coolant. Right now the upper radiator hose has normal pressure after resting overnight, and the engine oil analysis looks good, so I don't think I have problems with cracks in the head right now. Thanks for reading through all this! Very respectfully, /s/ Max Dillon '87 300TD 334k miles '95 E300 280k miles '73 Balboa 20 Charleston SC _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
