RMS thoughts

[Clemens]

I know my 96 R has a RMS leak. It must have had it for years before I bought it because the crossmember and underflorr are covered with a dirty oily cover reaching quite far back (alternative method of rust protection ).

I know I Need to get it replaced, but my indie will charge me around 1k, so I will get it done within the next years or so. Anyhow, the RMS went bad because in 275.000 k the had never got a pcv cleaning. After I did that and I have good vacuum at idle and so the RMS leak got better. Under slow and nice cruising conditions it barely leaks anymore, but if I drive it a bit quciker for a longer time 130-170k on the Autobahn with alot of acceleration and braking (lots of boost) I notice it leaks more when I park it afterwards. nu puddle, but a few drips. In the mornung I have like a quarter sized bright yellow oil spot under the car.

So, my question is:
Is my pcv not working properly under boost or is there alot of blowby at the rings or why is there more crankcase pressure under boost? I´d just hate to have a RMS Job done and haing to redo it (btw, my compression was at 14-14-14-14-13 bar [200-200-200-200-188 in psi], unfortunately measured with the trottle closed [stupid mechanic], so I feel the rings are okay)

[mecheng]

go to amazon and buy ATP-205, there is a good chance it will solve your RMS leak and oil pressure issue at start up. It completely cured my valve stem seal leak; 100% gone. My exhaust is getting rusty now because it burns zero oil.

[Clemens]

Thanks. Might be worth a shot. I heard that all these rubber softening additives shorten the lifespan of all rubber elements in the motor. But then , on the other hand, if this gives me a few more years w/o worrying about the rms i can overhaul the complete motor in a few years anyhow in case all the other seals go south.

[Clemens]

Btw, according to a post on bobistheoilguy atp205 only?works for?rubber type seals and eats plastic, teflon, delrin kind of seals as told by the producers of atp205. Do we have these kinda seals or other parts of that material in our motors?

[mecheng]

I've found no evidence both through searches and my work on the car that any seals in these engines are plastic, teflon, or delron and you can easily tell a rubber based seal from those. Plastic, and delron make terrible seals, I don't see them used in engines.

I've had no leaks from any seals, I've done a few inspections at all the normal sealing areas.

[erikv11]

Several people here have used ATP-205 here with no problems. E.g. moderator JDS60R has been recommending it on the site for maybe 10 years, he runs a shop and I am sure he would have heard about it by now if there were issues in Volvo engines. I've only used it 2 or 3 different engines but no problems.

Those psi numbers are way too high for a generic HPT engine like on your 96, maybe the gauge is not accurate? Anyway they are close together so that's good.

The reason to test compression with a wide open throttle is solely to keep the injectors from firing, if the mechanic disabled fuel supply some other way then it won't be an issue. Anyway the numbers might be low if fuel was getting in, seems to not be an issue here!

[Clemens]

The reason to test compression with a wide open throttle is solely to keep the injectors from firing, if the mechanic disabled fuel supply some other way then it won't be an issue. Anyway the numbers might be low if fuel was getting in, seems to not be an issue here!

Thanks, erikv11, this is a great explantaion to the old "you have to test with WOT. I had pulled the fuel fuses before he did the test. He said the numbers might be off, but I like the fact they are quite even.
Then I´ll try to order the ATP-205, might save me some cash

[tryingbe]

why is there more crankcase pressure under boost?

Boost = more air being forced to the cylinders = more blowby.

[Clemens]

Thank you!