17’ GMC 6.2 Whipple keeps blowing rear main seal

[Tanner Smith]

My rear main seal keeps blowing out on my 2017 GMC 6.2. The truck has a 56,000 miles on it. The charger has been on it for 4,000 miles. Why does it keep blowing the rear main seal? I put a catch can on it and it still blew the seal. The catch can grabs about 5 ounces of oil for about 100 miles. That seems like alot. I have to constantly keep an eye on the motor oil. I am going to do a compression check on the motor to make sure the rings are not shot. Could it be a problem with the PCV system? PCV Valve not opening? Any input helps a bunch. Thanks. 

[rlcole321]

Too much crankcase pressure, I imagine you have a cold air intake, where did you route the crankcase breather element?(maybe a picture), also are you running the 0W-20 recommended oil? Now the compression test would be a good idea. Also you could think about a vacuum pump system.

[pokismoki]

17 hours ago, Tanner Smith said:

My rear main seal keeps blowing out on my 2017 GMC 6.2. The truck has a 56,000 miles on it. The charger has been on it for 4,000 miles. Why does it keep blowing the rear main seal? I put a catch can on it and it still blew the seal. The catch can grabs about 5 ounces of oil for about 100 miles. That seems like alot. I have to constantly keep an eye on the motor oil. I am going to do a compression check on the motor to make sure the rings are not shot. Could it be a problem with the PCV system? PCV Valve not opening? Any input helps a bunch. Thanks. 

 check your pcv, .. you might have a backwards check valve in the catch can,

Edited August 6, 2021 by pokismoki

[Tanner Smith]

9 hours ago, pokismoki said:

 check your pcv, .. you might have a backwards check valve in the catch can,

It blew the rear main seal before the catch can as well.

[Tanner Smith]

12 hours ago, rlcole321 said:

Too much crankcase pressure, I imagine you have a cold air intake, where did you route the crankcase breather element?(maybe a picture), also are you running the 0W-20 recommended oil? Now the compression test would be a good idea. Also you could think about a vacuum pump system.

The passenger valve cover breather tube is routed into the intake tube, Then the driver side tube off of the valve cover is routed into the catch can, and then the other hose from the catch can goes into the side of the charger. I will get pictures. I am running 0-20, I want to run 5W-30.

[Tanner Smith]

12 hours ago, rlcole321 said:

Too much crankcase pressure, I imagine you have a cold air intake, where did you route the crankcase breather element?(maybe a picture), also are you running the 0W-20 recommended oil? Now the compression test would be a good idea. Also you could think about a vacuum pump system.

 

[pokismoki]

must have installed the pcv incorrectly, did you install kit?

[Tanner Smith]

1 hour ago, pokismoki said:

must have installed the pcv incorrectly, did you install kit?

Yes, I installed it. I'm almost 100 percent positive to hooked all the PCV lines up properly, I checked and checked many of times. I guess what I can do Is take it to a local shop that installs these kits and have them look over the PCV system to make sure it was all done correctly. I did a Compression check and all cylinders were 190-200. So It is definetly not low on compression.   

[pokismoki]

any one make a breather that replaces the oil filler cap?

[Tanner Smith]

2 hours ago, pokismoki said:

any one make a breather that replaces the oil filler cap?

yeah I found a guy on youtube that had did a k&N filter for the oil fill cap and as well as for the other valve cover. I am going to install those. But I am still not sure why the catch can has so much oil in it.

[pokismoki]

your piston rings are probably gumming up from oil being coked due to extreme heat, this bipasses oil into the pcv system and fills up the trap.

 

You have the wrong piston set up for a supercharger, get a set of  lower CR forgings and gapless rings

 your using the wrong oil if you use 0w20 not good!

 

i hope your not using the 220 F t-stat , your coolant temps are too high for boost? you have a lot of homework to do

Edited August 7, 2021 by pokismoki

[pokismoki]

you do have the AFM disabled right?

[Tanner Smith]

6 hours ago, pokismoki said:

your piston rings are probably gumming up from oil being coked due to extreme heat, this bipasses oil into the pcv system and fills up the trap.

 

You have the wrong piston set up for a supercharger, get a set of  lower CR forgings and gapless rings

 your using the wrong oil if you use 0w20 not good!

 

i hope your not using the 220 F t-stat , your coolant temps are too high for boost? you have a lot of homework to do

Yeah, I have read that these motors are fine supercharged for awhile. I know the piston and rings were not meant for the boost. I have the AFM Disabled. The truck put down 500 hp to the wheels. I am going to run 5W-30 and no more 0w-20, too thin!

[pokismoki]

try adding 1 quart of dextron transfluid to the engine before oilchange,  drive couple miles till warmed up then change oil. this might free up stuck piston rings every 4000 mile oil change

[pokismoki]

try installing a set of UNI  valve cover breathers , i think its 5/8" and plug the port to where the breather hoses connect

 

https://www.amazon.com/gp/product/B000OO0XOA/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

 

i ordered a set for mine I'll let you know if it works.

 

Edited August 17, 2021 by pokismoki