mkhargrove

They're on a sealed environment, so I don't know that it matters. But, would coating actuator diaphragms with silicone grease (which doesn't not cause breakdown of rubber) likely extend the life of the diaphragm?

I haven't found any metrics to show how much added life silicone might add, but there seems to be a consensus that it does extend life of rubber....

Landseer

I lubricated intake boots with it and they cracked faster than expected.

Those actuators have gotten expensive. I probably wouldn't.

dr bob

The little rubber cup that is the moving part of the actuator doesn't really rub against anything. It folds back on itself when vacuum is applied, and seems to tear at the point where the fold first appears. I'm not sure that any grease would do much good. If you were thinking that it would somehow protect the rubber from smog products... You might do as well leaving it in its plastic bag while installed.

Seriously, I think they are probably EPDM so pretty immune to most things in the car. The failures are as likely mechanical as chemical breakdown.

mkhargrove

i assumed the rubber begins to crack from drying/oxydation on the surface. my thought was that maybe a coating of silicone would slow that process.

linderpat

I have heard, and others will surely chime in, that silicone actually speeds up the breakdown of the rubber/plastic material. I avoid it in those applications. Will be interesting to hear what others have to say.

Mrmerlin

I put the DC111 on the rubber pod boots never had a problem. and it will extend the life of the rubber as it wont dry out
Chris The intake boots cracking is from hydrocarbons going after the rubber,
I have also seen this happen after fitting new collars usually without grease
IDK if the grease would speed that up,
but I have seen different brands/MFGs of the collars that deteriorate quickly compared to originals