VW 1.8T engine sludge

[bigmo460]

thread89-141793 Some engines are prone to making sludge. It is in the design. It seems to be in the PCV system design. What appears to happens the oil oxidizes, turns to sludge and can't be pumped, therefore failing the engine. Best solution is to use synthetic oil and change often. The important thing is to change often. I've known engines that missed a 3k mile oil change and failed.

 

[HarrisDE]

I'm curious, why would it be in the PCV design?

My assumption was high head temp differentials, low overall volume and long change intervals combined to make the prob.

I had a 1.8T in a 2000 Passat and it developed sludge. I ran synth and did my own changes every 5,000 miles. (You would think I'd know better). At 70,000 miles I had to drop the oil pan and scrape the junk out because it was clogging the pump screen.

Strangely my German freinds have never had this problem on their 1.8Ts.

Scott

 

[bigmo460]

Don't think I can give you the reason. I know that when we changed the system we reduced the gelation of the engine. Possibly we changed the presentation of oxygen to the oil resulting in less forming of jel by oxygenation? I believe that If the engine is operated in cold ambients and short trips would contribute to the problem. There is a phenomenon that when some oils are cooled at a certain rate they can form a gel and be unpumpable. But I dont think that is this problem. ASTM has a test for the oxidation (D4742). The longer the time in this test the better?? I wonder what the German friends are using for oil, how often changed and driving cycle? I think Euro. oils are typically better than U.S. oils!