My VVT seals are weeping a little oil so I have bought some replacements, not genuine but from a reputable source.

They seem very hard when I'd have thought a more pliable rubber would offer a better, longer lasting seal.

There must be a reason for this - can anyone tell me?

Mike

 

Soft wears faster its the oil that provides the lubrication.
How did you know they were leaking ? You got the engine apart?

 

I may be referring to the wrong part - it's the camshaft cover oil seal for VV sensor. (I haven't taken anything apart).

 

so it does not have anything rotating in it .......good
I dont go looking for trouble .I work on the big bang theory ..I am waiting for the big bang.

 

These VVT O-ring seals sit there on top of the engine and bake in the engine bay. I have long wished that a supplier would make them from more durable materials, but that is simply not the case. I have tried OEM ones and aftermarket ones. Regardless of the source, they tend to last me a couple of years before they begin to weep oil. I am currently on my fourth pair....

 

I have the same issue on my 06S type R. Got an oily film coming out around both parts on both valve covers

 

I just checked the seals that I ordered from Welsh. They are hard on the outer side but are more pliable on the inside diameter. It might be a design to insulate some of the engine heat from the sensors.

 

I noticed a slightly eroded ring around my VVT solenoids where the seal contacts the solenoid body, maybe road grit gets in there and wears on the solenoid due to vibration.

I masked, lightly sanded and painted the seal contact area with caliper paint, no leaks after 2 years.

 

i used the uro for a v6 with gummy rubber. worked great on my x350 not so much on the str.

honestly go genuine from the ford dealer install them properly otherwise you will always have them leaking after a couple years

 

Since they can leak air, it is a good idea to not ignore them. I have had great results with Ford parts and then sealing them to both the valve cover and solenoid with some Permatex Black. No oil weeping years later. Easy to remove if one is careful. Made a big difference in fuel trims. They start to admit air after only a few months in service.