Hey everyone,

My truck had an Airaid intake with a K&N filter when I bought it and I am debating about going back to the stock setup. I recently had some work done to the truck which included extending the crank case vent down by the axle. After getting the truck back I started seeing a lot more gas out of the vent than I had expected. I checked blow by out of the oil fill cap and it also had more than I liked, so I started reading. I ended up holding my thumb over the vent trying to see how much blow by I had. I held it for about 20 seconds and just as I was about to let it go I heard a pop and a hiss and had oil everywhere. I thought that the dipstick would pop and the gas would vent out the tube before anything broke, but I was very wrong. The tappet cover gasket blew out and I'm still not sure what else. I picked the truck up from my mechanic yesterday and it was still leaking. I'm really hoping its just the oil pan gasket but I don't know yet. I also had the blow by tested last week and was told it was within spec, so (even better) the whole thing is caused by me, once again, trying to fix something that isn't broke. This long story all leads to my question, are washable filters such as Airaid and K&N more likely to cause dusting and blow by? Is it best to just stick with stock? I don't know how long the current setup has been on there. The truck is at 250,000 and I am trying to make it last to at least 500,000 so I want to take the best care of it that I can.

 

You seem to have several things going on here so I address them one at a time.

The Airaid/K&N filter should not have let a lot of dirt by at all. If it did, you would see dirt caked on the intake tube surface before the turbo, and on the leading edge of the turbine blades. So unless you see a lot of dirt caked up in the intake after the filter, this is not likely the cause of your problem.

Extending the vent tube down is a great idea. Definitely saves your radiator from getting really dirty.

Our engines do not use positive crankcase ventilation (PCV), the crankcase is simply vented out to atmosphere. The vent tube is usually the only outlet for the crankcase gasses. You just learned the hard way why it's important to not let the tube get plugged, it blows out seals. Hopefully it was only your valve cover gasket and nothing else that popped.

All engines create blow by, even when new. Cummins has a specification for how much is acceptable and how much is not, by testing with a manometer. Worn out rings will cause lots of blowby, but there is a much more common problem with our engines that can create blowby, and finding it does not involve tearing the engine apart.

It's the vacuum pump. Since diesel engines don't have a throttle valve in the intake, they don't naturally create vacuum like a gas engine would. That's why we have a vacuum pump in order to run the cruise control servo, all of the air conditioning vents, and the central axle disconnect (CAD) if yours is 4x4. The "exhaust" of the vacuum pump goes into the crankcase. It is also lubricated with engine oil, so that drains back into the crankcase as well. If you have a vacuum leak, a lot more air will move through the vacuum pump, and into the crankcase, giving the illusion of a bad blowby problem when it's really the vacuum pump.

Now the power steering pump is driven off of the same shaft as the the vacuum pump, which is driven off of the accessory gear in the timing case up front. The vacuum pump needs lubrication, but the power steering pump does not. So there is a single lip rubber seal at the back of the vacuum pump shaft to keep air out (a source of a vacuum leak) and the oil in. This seal has failed causing issues for a lot of Ram owners, myself included. The fix for it involves pulling the pump and resealing it with a seal kit which features a double lip seal. If this seal got blown out too when you plugged your blowby tube, then it can leak a substantial amount of oil. It's easy to find though, on the lower drivers side of the engine, forward of the starter.

250,000 miles is OK, and your piston rings should still be fairly tight to the cylinder, especially if there is no dirt in your intake tube and turbo. More than likely, it's your vacuum pump.

 

The gasket blew because the blow by pressure is in the lifter bay, not the crankcase area...

The K&N was the must have filter when the Cummins first came in the dodge but was found to let dust and other fine particles through, mainly because the intake air sucked the fabric through the mesh IIRC.

Dry paper media is still highly regarded as the best filtration til you get into ridiculously small particles.

boistheoilguy.com has great info on anything filter..

I run a NAPA BHAF on mine and it has been in there since 07. It looks dirty, but is still white on the inside and the filterminder is below 10%...You need to make a heatshield, though , if you go this route.

The stock airboxes tend to break at the bottom which is the area of clean air out. That can let dirty air into the turbo.

 

Here's some pictures to help visualize where to look.

Here's the vacuum pump and power steering pump assembled together as the would be on the engine. The vacuum pump is on the left, power steering pump (black) on the right. On the bottom of the vacuum pump you can see a threaded fitting, that's where the oil feed line goes in. The shaft seal is about an inch or two to the right of the feed line fitting.





In this picture I have the pump standing on it's nose. That shaft seal is visible in its collar in the middle of this picture. Is the black ring.




And lastly, here's a shot of the power steering pump shaft, that sits inside that seal. As you can see here, the original single lip seal has worn a small groove into the shaft causing both a vacuum leak, and an oil leak. This is a very common problem for a lot of Ram/Cummins owners.

 

Thanks for all the great info and pictures guys! I really appreciate it! I don't have the space to work on the truck myself so right now I'm waiting for my mechanic to look at it again as I am pretty sure it blew the oil pan gasket as well, hopefully nothing else ...I'll have him look into the vacuum pump as well and see what he thinks....as far as the air filter goes, I am going to have to buy a factory setup if I want to go that route or the BHAF route because the Airaid tube is huge and I haven't been able to find any filters other than k&n to fit it. So my next question is, how about an S&B intake with a dry filter? I've done a little bit of reading so far and it sounds like they are supposed to be really good. What do you guys think?

 

For filters I have no experience beyond the stock setup, a BHAF, and a Scotty Air II. Any of those three will do well. Might get lucky and find a stock setup at a salvage yard.

The pan gasket should be fine. Once the first gasket blows and releases the built up pressure, the other gaskets should be ok. Key word there is should, nothing is out of the realm of ordinary with a blowout like this unfortunately.

The vacuum pump oil leak can look like a pan leak since they are very close to each other. You just have to look at it while it's running to know for sure where the leak is. I am leaning this direction due to your earlier "blowby" problem. That's easy to see too. When I resealed my vacuum pump, I knocked the seal out of place when I put the power steering pump back on and had a nice big oil leak when I started it up. Had to pull it a second time and reassemble the whole thing out of the truck and put it back in.

The vacuum pump will be the easiest and cheapest thing to eliminate as the problem. If that checks out, then the problem is inside the engine. As a test you could disconnect the main vacuum line at the pump, and plug it. That would eliminate any air leaks to cause vacuum pump blowby. Once the vacuum system and gaskets are in order, the manometer test will tell the tale for the engine internals.

 

The NAPA filter I have plugs right into the 4" factory turbo elbow.

I re-read what I wrote last night and realized I misled you on the blow by, there would be pressure in the crankcase also, just the oil pan gasket is relatively thin and well secured, the valve cover gaskets less so. I think the dipstick wouldn't push out because there is a lot of resistance on the unit...

Jr's diagnosis sounds on the money. Unless your engine was run hard and ill-serviced, your blow by should be minimal at that mileage.

 

SIXSLUG,

How do you have your filter secured? Is it just sitting on the fender or what? Also, do you have any kind of heat shield? I have read quite a bit about people making heat shields to use with the bhaf but I also read something that said the intercooler makes a heat shield unnecessary. What do you think?

 

Mine is inletted into the elbow and secured by the factory clamp.

I made a heat shield to reduce heated air off the exhaust manifold and turbo, which is right next to the BHAF. There used to be a template on this site for making it out of cardboard, then transferring to aluminum, which is what I did. With a few modifications for a better fit.

One thing to watch for is the factory hold downs for the stock box, they will wear holes in a BHAF....

I'll take a few photos of my setup and post them.

 

Sweet thanks!

 

Here's what the BHAF (Big Honkin Air Filter) looks like. It's more meant for stationary engines, like a generator, and not so much for a truck. You'll have to take care to clamp the hose well on the filter neck, and don't over tighten it. Mine in this picture does not have a heat shield.

 

Thanks for the pic! Is the hose really stiff then? more like a pipe than a hose? pardon my ignorance as i don't have one lol

 

Does anyone have any good/bad experiences or factual numbers comparing BHAF to OEM to S&B? I really like the idea of the S&B with a dry filter and filter wrap but I am really concerned with protecting the engine the best that I can and I'm not sure if the S&B has been proved to be as good as OEM. I am also still considering BHAF and OEM of course. I just want to be sure before i buy anything since I have to purchase an OEM intake to go with stock or BHAF.
Thanks for all the great info so far guys!

 

Here's another question on the blow by, if my truck passes a manometer test do I need to worry about the vac pump if it's not the cause of my oil leak?

 

Yes, you still need to worry about the vac pump. If you have a vacuum leak, that will give a false indication on the manometer test (high blowby). A vacuum gauge will help to to determine if there's a leak and the overall health of your vacuum system. I think I paid around $20-30 for a Craftsmen gauge years ago. Plus they are a very good diagnostic tool on gas engines.

The vac pump oil leak, is a fairly straight forward repair. Cummins has a reseal kit that you can buy, as does Geno's Garage.

For the filters, a lot of them do well. The only ways to know if a filter is doing poorly, is evidence of dirt in the intake piping, and sending in an oil sample for analysis. The BHAF has a similar flow rate to the OEM square filter.

And for your other question, that intake hose is somewhat flexible. I've been able to use that on all three filters I've used.

I do reccomend the oil analysis. It will show you all of stuff that may be in your oil, like metals (engine wear), silicon (dirt), oil quality, coolant, fuel. That, plus the manometer test will give you the data you need to know your engines health. It's really hard knowing if your engine really has a problem without good data