Hey all,

Having a pressurized crankcase condition, I've cleaned the heck out of everything, when I blow into the top of the separator with a hose, I can definitely blow into the block, so I don't know what could possibly be happening besides the blowby thing.

Now, if I started it with the separator off....so I can guarantee excellent crankcase ventilation...will it spray oil everywhere?

I would only run it long enough to lay a paper towel over the oil filler hole in the valve cover.

1989 240DL

A lot of old engines have run for a long time without any sort of recirculating crankcase ventilation so it will not hurt anything.

If you are interested in tracking down a blowby issue you should check the compression. You can probably rent a gauge at any chain auto parts store.

Check the compression on all cylinders and then add a tablespoon ( or a few squirts from an oil can) to each cylinder and check the compression again. If the compression numbers come up a lot after you add the oil the rings are probably worn, causing your blowby problem.

Greg

I believe all the plumbing would have to be in place and properly attached for there to be the slight vacuum condition you are looking for.

I would use a piece of printer paper or some paper stock that is not as porous as a paper towel.

Randy

Not sure you understand what I'm trying to do.
My engine is currently acting like the flame trap is clogged.
it's blowing out the oil filler cap badly The crankcase is pressurized. Previous owner had to RTV silicone it on and also did that to the water pump and just tried to seal everything because it was 'leaking' so bad. Now the system is too pressurized and it's going to blow the seals out. I want to run the motor for a few seconds with the flame trap and separator off, to rule them out. I've cleaned all that stuff, it is passing air through all tubes and hoses fine, and I have a strong 25lbs of intake vacuum sucking on that flame trap and it's still pressurizing the valve cover. I want to try it with all that stuff off, to see if it stops 'puffing' so much air out at the filler hole. I've read its a good test to lay a piece of paper over it to see if it gets sucked down or blown off. In my estimation, if it just kinda lays there....then it would seem like the flametrap and oil separator are still constricting air flow. Just wondering if its going to blow oil like crazy out of the hole where the oil separator goes, if I start it like that for a minute.

Connect everything so you have vacuum inside the crankcase. you have to let the crankcase breath. New gasket under the oil fill cap.

Not sure you understand what I'm trying to do.
My engine is currently acting like the flame trap is clogged.
it's blowing out the oil filler cap badly The crankcase is pressurized. Previous owner had to RTV silicone it on and also did that to the water pump and just tried to seal everything because it was 'leaking' so bad. Now the system is too pressurized and it's going to blow the seals out. I want to run the motor for a few seconds with the flame trap and separator off, to rule them out. I've cleaned all that stuff, it is passing air through all tubes and hoses fine, and I have a strong 25lbs of intake vacuum sucking on that flame trap and it's still pressurizing the valve cover. I want to try it with all that stuff off, to see if it stops 'puffing' so much air out at the filler hole. I've read its a good test to lay a piece of paper over it to see if it gets sucked down or blown off. In my estimation, if it just kinda lays there....then it would seem like the flametrap and oil separator are still constricting air flow. Just wondering if its going to blow oil like crazy out of the hole where the oil separator goes, if I start it like that for a minute.