Suggestions needed for vw bug oil bath oil weight

[sagaboy]

The oil bath filter oil in my old 1500 stock vw bug remains clear and clean even after a year and thousands of miles of driving. I am using 20/50w multigrade oil in the oil bath and the oil bath temperature after warm-up is 140/160 F

Could the oil stay clean because…
1. The air is cleaner where I live
2. Air is leaking directly into the carburetor – I have checked and it is not
3. The 20/50w multi-weight oil is too thick when warm-up to work well and I should change it to a lower weight or straight weight oil.

Any suggestions appreciated thanks

 

[TR3-2001SE]

My old Mercedes Benz 240D used oil bath and I always used straight 30 weight. I guess the manual must have recomended that weight. Not sure if was non detergent or not. It was always dirty when I checked it so it was definitly working.

 

[Jim Allen]

Would viscosity even have an effect? I doubt it. The oil is just a "sticky" medium to attract dirt. Heavy oil does that just as well. The only problem I can see is that some of the oil should vaporize and be drawn up into the filter mesh. This makes the mesh tacky and catches even more dirt. My thoughts on oil baths was always, if some of the oil is obviously used up when I clean it, then it's doing the job. And, of course, how much junk is in the bottom. Here's a test. Find some really sticky high temp grease and put a smear of it in the air flow past the filter element but before the (supposedly) clean air goes into the carburetor. Run for a while, maybe even on a dusty road. Check the grease. If it's attracted dust and grit, you know you have a problem. If not, you can figure on item one on your list.

 

[sagaboy]

Thanks Jim

Good suggestion.