Vacuum line size?
 

1989 300SE. Need replacement tubing - clear, but I cannot find part number. I'm not even sure of the exact size. I know there are several of the same in use and I want to replace them all. The line in question is the clear line that comes from the crankcase ventilation hose.

It would have helped if you had just measured and stated the OD, but it sounds like you're talking about the 1/8" OD nylon tubing that vents the fuei pressure regulator (in case of a leak) to a molded in nipple on the PCV hose, and on my 190E 2.6 is also used on the vacuum line to the EZL.

I bought a few feet from a MB dealer, but that was probably 15 years ago.

Duke

This is what you need. Replace all the rubber fittings as well.

https://www.pelicanparts.com/More_Info/0019973952.htm?pn=001-997-39-52-M22&bc=c&SVSVSI=2419

I believe we're all talking about the same tubing. I just measured what is used on my '88 190E 2.6 for the FPA vent line to PCV hose and inlet manifold to EZL and it's right at 4 mm OD.

Is there more than one size to this type of tubing?

Duke