Crank case pressure relief valve

[Johnboy]

I wonder why cummins put a relief valve in the filter housing for the crank case filter???????
I removed mine but it made me wonder a little bit why nobody else has mentioned this maybe nobody has found it yet. Remove the filter and it's in the lower left corner pop it out with a screw driver and put the filter back in problem solved.

[Waterloo]

We were all drilling holes in our filters, probably why and or ever noticed one... Cummins has a new drop in that now breathes freely, no filter element. Install once and forget about it. I don't have the part number, but I run one as do many here.

[Johnboy]

Noted. I wanted to let everyone know there is a relief valve in there. remove it and you don't have to buy a new filter the hole is a 1 inch flow thru the back side of the filter. Beter than a 1/2 inch hole in the top twice the flow.

[Billdozer2]

(02-05-2017 )Waterloo Wrote:  I don't have the part number

Part Number is 3691476

[Rawze]

(02-05-2017 )Johnboy Wrote:  Noted. I wanted to let everyone know there is a relief valve in there. remove it and you don't have to buy a new filter the hole is a 1 inch flow thru the back side of the filter. Beter than a 1/2 inch hole in the top twice the flow.

I have seen several others that have done this already in the past. It has not been overlooked, and is not a new idea. You get away with it a new engine, but is less effective on an older one.

My experience with others that have done what you are recommending instead of drilling a 1/2 hole ...

The 1/2" hole (even if you have to put one on each side of the filter element if your engine has a lot of blow-by) drilled into an existing filter element in the place shown does a couple things. It forces the fumes to still go around the sides of the filter element and upwards before venting again. This slows the fumes down by quite a little bit and makes it catch more oil mist as it does so. I have had several people say that even the cummins no-element replacement (similar effect to what you are doing) contributes to quite a a bit more oil loss, resulting in an oily mess under the truck after a while on an older engine. Most who have done that notice it after a while and end up going back to the paper element type and drilling a 1/2" hole in it instead.

Also, if your truck is so bad that a 1/2" hole is insufficient, and you are still getting excess crank case buildup then your engine is done and you are ready for an in-frame.

There is an exception to using only a 1/2" hole for extreme cold environments. Some people who use their truck in the extreme cold environments of say northern canada have had problems with icing of the element in (like -20 temps) extreme cold. Sometimes the crank case filter will ice-over too easily (filter element or not). They will sometimes resort to completely bypass the crank case filter all together, or remove the entire center part of the filter element itself to combat this. The CM2350 engines have a crank case heater and insulation on the cover to prevent this.

[gearhead]

Some cm2250 had this heater also although rare.