Air Filter Restriction Indicator

retmil46 · **Posted:** Wed Apr 12, 2006 1:27 am

On my friend's '04 Dodge Cummins, they have a air filter restriction indicator/gauge mounted right into the side of the air filter housing. This is a small cylindrical device, about 1 1/2" diameter and less than 3" tall. On the Dodge, it's basically a one piece affair, that fits into a hole in the filter housing with a rubber grommet.

Basically, the whole purpose is to give you a visual indication of how clogged you air filter is getting and when it's time to change it out, instead of having to make an educated SWAG on your own.

We install essentially the same indicator on the air filter housings on all the Freightliner trucks. Main difference is, the air filter housings have threaded 1/8" NPT ports they screw into. There's a straight thread O-ring fitting that screws into the indicator, and a 45 degree elbow that adapts from the straight thread to 1/8" NPT.

On the Freightliner indicators, 25" H2O is the point calling for filter changeout. They lock in the highest vacuum reading they've seen to date, and have a scale on the side with marks at 8, 11, 15, 18, and 25 inches H20 vacuum.

I obtained one of these indicators and the two fittings, with the idea of seeing if I could adapt it to the air filter housing on the CRD.

After doing a fit check under the hood, I don't see any realistic location where you could mount the indicator directly on the air filter housing.

However, I think it is quite feasible, given the size of the indicator, to do a remote mount a short distance from the filter housing. My plan is to drill and tap a 1/8" NPT hole in the top part of the filter housing facing back towards the firewall, and install a barbed hose connector. Then run appropriate sized vacuum tubing from this fitting to whereever the indicator is mounted.

If nothing else, it'll be interesting to see how much of a vacuum that turbo can pull during normal driving with the stock inlet. I'd say that if it can peg that indicator right off the bat, even with a fairly new filter, then we definitely "need a bigger boat". It does pull some sort of vacuum on the air intake, even at idle, from the way I saw air frothing up into the drain tube on the Provent when it developed a leak around the drain plug.

RFCRD · **Posted:** Wed Apr 12, 2006 8:23 am

I have the same device in my Chevy pick-up (gasser) but much smaller in overall size. It's a Donaldson part. I have been wondering if this model would work on this diesel. Have a service appointment for Saturday at the Chevy dealer. They sell a lot of diesel trucks, plan to check with them.

RFCRD · **Posted:** Wed Apr 12, 2006 10:06 pm

I was looking at installing into the backside of the air filter cover. Would stick out toward the rear, on it's side between the p/s resivoir and the vac controller for the turbo. Need to check if the lid has clearance to hinge open. Probably fit as snug as the Provent.

oldnavy · **Posted:** Wed Apr 12, 2006 11:10 pm

I even seen them adapted to VW diesels.

retmil46 · **Posted:** Wed Apr 12, 2006 11:34 pm

RFCRD wrote:

I was looking at installing into the backside of the air filter cover. Would stick out toward the rear, on it's side between the p/s resivoir and the vac controller for the turbo. Need to check if the lid has clearance to hinge open. Probably fit as snug as the Provent.

Yep, that's why I'm saying that doing a remote mount would be a better option. Just install a 1/8" NPT to barbed hose fitting in the filter housing, then route a length of vacuum tubing to where ever there is a convenient location for strapping down the indicator, and attach it to the indicator with another barbed hose fitting. They actually have dash mounted air restriction indicators on the big rigs and that's all they do - route vacuum tubing from the air filter housing to the indicator on the dash.

RFCRD · **Posted:** Thu Apr 13, 2006 6:24 am

A dash mounted gauge would be handy. I'd still like to know if that air box & fliter can flow enough air for WOT and how clean the filter needs to be to maintain flow. What is spooky is that I really haven't put this motor under any sustained load, just the occational passing manuver. Hook-up a heavy wagon and find a long grade of @ 6%, I'd bet lunch it can't keep up with the draw of that turbo.

oldnavy · **Posted:** Thu Apr 13, 2006 7:16 am

RFCRD wrote:

A dash mounted gauge would be handy. I'd still like to know if that air box & fliter can flow enough air for WOT and how clean the filter needs to be to maintain flow. What is spooky is that I really haven't put this motor under any sustained load, just the occational passing manuver. Hook-up a heavy wagon and find a long grade of @ 6%, I'd bet lunch it can't keep up with the draw of that turbo.

It will or it will suck the filter into the turbo. In the mean time we may have to do a more often change. I pulled the tube going into the airbox from the front of the Jeep and put a round piece of door/window screen wire over the end of the tube and shoved it back in place. Will see haow that helps.

KJbob · **Posted:** Thu Apr 13, 2006 12:08 pm

Has anyone used one of these thingies?

http://www.filterminder.com/

I posted this link on another thread discussing the frequency of changing air filters

retmil46 · **Posted:** Fri Apr 14, 2006 12:04 am

KJbob wrote:

Has anyone used one of these thingies?

http://www.filterminder.com/

I posted this link on another thread discussing the frequency of changing air filters

That's the very same "thingie" I've got sitting here on my desk. The indicators that Freightliner installs are these same Filterminders, with the Freightliner logo added. They also have smaller ones made by Donaldson, but they're basically go/no go gauges, no indication until the differential pressure across the filter hits 25" H2O, and then the red indicator pops up. With the Filterminders, you can see how much D/P you get across a fresh filter and see how fast it's clogging under different conditions.

Filterminder also makes a similar gauge that you can install in the fuel line and will tell you when your fuel filter is starting to clog up. That could be another useful little item.

retmil46 · **Posted:** Sat Apr 15, 2006 1:36 am

Installed the Filterminder style indicator today. Turns out I actually had enough room, with the 45 degree elbow, to mount it directly to the back side of the air filter housing, pointing towards the firewall, inclined at about a 60 degree angle.

Current air filter is dealer OEM with about 1000 miles on it, and running minus the air inlet tube to the grill. Did a trip to the hardware store this evening, 5 miles each way, stop and go max 45 mph with OD off. Tried some mildly aggressive acceleration, up to around 2400 rpm, no WOT however.

When I got home, I checked the indicator. It hadn't moved, still reading zero. I had rather expected it to at least be locked in at the first graduation, 8" H2O, but it wasn't showing any reading. And yes, I did verify it was working prior to installing it.

Even if it only locks in at each graduation, that still means the turbo was pulling less than 8" H2O across the filter during acceleration. You can easily peg one of these indicators at 25" H2O by putting it up to your lips and applying a mild suction.

First impressions - Unless you're really going to hot rod this beast to ungodly power levels, a K&N or other "high flow" air filter looks to be a waste of time. Granted I was running without the inlet tube to the grille, but initial indications are the stock air filter and housing are more than adequate for normal driving and acceleration (ie, below 2500 rpm). As far as heavy towing or lead footing it at higher rpm's, that's still an unknown.

Also, I wouldn't rule out a reuseable high filtration efficiency (NOT high flow) filter as yet. Only time and miles will tell just how long it takes to clog the stock filter to unacceptable levels with mostly highway driving.

spoonplugger1 · **Posted:** Sat Apr 15, 2006 11:27 am

I wouldn't concern yourself with being able to pull a load with the CRD, my buddy traded in his 2 year old F-150 for one after being humiliated at the pump and in the mountain passes by my rig for almost a year. Pulled a loaded two horse trailer out of the mountains after my neice got snowed in on a horsebacking trip. The trailer was loaded with two full size Tennessee Walkers and gear.

RFCRD · **Posted:** Sat Apr 15, 2006 12:02 pm

There is definately no problem with enough grunt to pull with this rig. It's an issue of pulling without polluting your CAC with oil which can come from two different sources, the CCV, or through the turbocharger center bearing oil seals. The CCV can be filtered but the turbo seal leaks are usually a function of air intake vaccume. It becomes easier to suck oil through the seals than draw air through a marginal air filter.

I just got home from getting my Impala service at my Chevy dealer (big into MD trucks and services a lot of diesels). Their SM told me they see the same thing from time to time on the D-Max. Told me road salt in the filter is a problem, suggested a fresh filter every Spring as soon as the salt trucks are parked. Also, he about fainted when I mentioned 0W40 for recommended oil.

oldnavy · **Posted:** Sat Apr 15, 2006 1:56 pm

RFCRD wrote:

There is definately no problem with enough grunt to pull with this rig. It's an issue of pulling without polluting your CAC with oil which can come from two different sources, the CCV, or through the turbocharger center bearing oil seals. The CCV can be filtered but the turbo seal leaks are usually a function of air intake vaccume. It becomes easier to suck oil through the seals than draw air through a marginal air filter.

I just got home from getting my Impala service at my Chevy dealer (big into MD trucks and services a lot of diesels). Their SM told me they see the same thing from time to time on the D-Max. Told me road salt in the filter is a problem, suggested a fresh filter every Spring as soon as the salt trucks are parked. Also, he about fainted when I mentioned 0W40 for recommended oil.

You should not have seals leaking like you describe on a turbo, when your turbo starts leaking oil at the seals it doesn't take long and you will have a dangerous situation with a run away turbo. The Only place the CRD, D-Max or Cummins should be having oil coming into the turbo from is the CCV system. Sounds like your diesel teck is living about 10 years in the past and is not up on the new engines, oil requirements and advances in oil or diesels from what you say.

RFCRD · **Posted:** Sat Apr 15, 2006 6:37 pm

I can agree that you should not see oil passing the turbo seals but it has happened on my CRD and I had this once before on a Series 60. Both times it was a filter. I wouldn't call this SM's advise to run at a CI-4 or CI-4+ rated oil and maintaining a dry CAC as outdated. He was quick to point out that he has yet to see a 0W40 that was CI-4 rated, suprised to see it recommended in a contemporary diesel. But what do they know, they service GM stuff and a lot of CAT in their trucks. When they see a wet CAC come in (and it does happen), they try the cheapest thing first. They change the air filter and clean the lines then run it for awhile before going wrench happy. He was also quick to point out that the CRD is probably a better diesel than most people think. This is from a hardcore bowtie guy.

oldnavy · **Posted:** Sat Apr 15, 2006 7:22 pm

RFCRD wrote:

I can agree that you should not see oil passing the turbo seals but it has happened on my CRD and I had this once before on a Series 60. Both times it was a filter. I wouldn't call this SM's advise to run at a CI-4 or CI-4+ rated oil and maintaining a dry CAC as outdated. He was quick to point out that he has yet to see a 0W40 that was CI-4 rated, suprised to see it recommended in a contemporary diesel. But what do they know, they service GM stuff and a lot of CAT in their trucks. When they see a wet CAC come in (and it does happen), they try the cheapest thing first. They change the air filter and clean the lines then run it for awhile before going wrench happy. He was also quick to point out that the CRD is probably a better diesel than most people think. This is from a hardcore bowtie guy.

I guess I failed to read your post properly. However if the CRD was running ULSD (as in Europe) then there would be no problem with that 0w-40 M 1 oil for most users, but then I still would use the M 1 T&SUV oil as I currently have in the CRD since the oil change at 4000 miles. As far as oil seal leaks on turbo bearing that can happen if air intake is greatly reduced, but most diesels I ever saw would just injest the airfilter before sucking out the oil seals in the turbo. However as we use to say in the USN, nothing is sailor proof.

RFCRD · **Posted:** Sat Apr 15, 2006 8:20 pm

The Series 60 almost inhaled the filter. Imploded the round element, just couldn't get the 2ft filter through the 8 inch hole. It was a sight to see. CAC lines were 4" steel tubes, used a floor mop soaked in ether to swab them out. Talk about a bad day, that was a job. All that from driving on a dirt road.

Along same the lines as a CCV, a common mod on OTR buses is to eliminate the lavatory electric exhaust fan. Replace it with a 2 inch diameter suction hose straight to the air cleaner housing. Did it on all mine, best exhaust draft you can get.

Air Filter Restriction Indicator

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