Engine air filter / canister question

Topic: Engine air filter / canister question (Read 978 times) previous topic - next topic

Engine air filter / canister question

May 15, 2021, 03:42:19 pm

Hi everyone

We have owned this coach almost 2 years and our air filter minder has never moved.
I took off The hose from the air filter end and sucked on it and the filter minder did move up to the top red part.
We have put approximately 20,000 miles on the coach since we bought it.

I purchased an air filter from Napa(hope it's a decent one) and Will be installing it soon.

I have noticed a small hole at the 2 o'clock position on the air filter canister. It's not from rust and is perfectly round almost 1/8 of an inch in diameter.

1-Does everyone else have this hole on the canister?
2-Is it supposed to be there ?
3-will it affect the filter minder's performance?
4-Is there any other way to check the filter minder to make sure it's working properly?

Re: Engine air filter / canister question

Reply #1 – May 15, 2021, 03:54:10 pm

You did check the air filter minder. Sucking on the hose should peg it and it should hold that reading until you push the reset button.

Since it looks like your air enter the OUTSIDE of the filter and exits toward the turbo from the INSIDE/CENTER make sure your air filter has wire mesh support on the INSIDE. Can also have it on the outside-- but not necessary.

Said another way, the exact same filter element shape can be used on applications where "dirty" air enters to the outside of the filter element OR from the inside. It is CRITICAL that the filter one uses is supported on the correct side so the filter media is not sucked apart by the pull of the turbo.

Re: Engine air filter / canister question

Reply #2 – May 15, 2021, 04:39:17 pm

Yes, wire inside & outside and new gasket for the cover

Any thoughts on the hole in the canister?

Re: Engine air filter / canister question

Reply #3 – May 15, 2021, 04:44:13 pm

Since the holes are both small and on the "dirty" side of the filter, I don't see an issue. But, also don't have a problem with your plugging them.

While you are there, have you checked the "duck bill"/water drain in the bottom of the canister. They are inexpensive and do not have an infinite life, being rubber.

Re: Engine air filter / canister question

Reply #4 – May 15, 2021, 04:59:03 pm

Quote from: Lt403 – May 15, 2021, 03:42:19 pm

Hi everyone

We have owned this coach almost 2 years and our air filter minder has never moved.
I took off The hose from the air filter end and sucked on it and the filter minder did move up to the top red part.

Most likely the 90 degree fitting is plugged - mounted on the lid of canister.
The small hole on the side will not affect the filter minder.

Re: Engine air filter / canister question

Reply #5 – May 15, 2021, 05:11:25 pm

Quote from: Doug W. – May 15, 2021, 04:59:03 pm

Most likely the 90 degree fitting is plugged - mounted on the lid of canister.
The small hole on the side will not affect the filter minder.

Correct, as they are on the "dirty" side.

Re: Engine air filter / canister question

Reply #6 – May 15, 2021, 08:14:40 pm

I seem to remember a discussion that the small hole in the air filter is necessary for proper operation of the filter minder.

Re: Engine air filter / canister question

Reply #7 – May 15, 2021, 08:36:39 pm

That's what the hole is for.

Re: Engine air filter / canister question

Reply #8 – May 15, 2021, 08:40:51 pm

Please explain.

Re: Engine air filter / canister question

Reply #9 – May 15, 2021, 08:47:38 pm

The suction side of the filter is in the middle so the hole is necessary so the air between the filter and the cap which is dead
air can be opened to the filter minder.

Re: Engine air filter / canister question

Reply #10 – May 15, 2021, 08:57:43 pm

If your air filter sucks from the outside in, you may need the filter with the small hole in the middle and a foam/rubber gasket on the same end. I bought a Cummins filter for our Detroit without the hole and gasket but just punched a hole and used the old rubber gasket. See my old post for photos. Easy to tell if you need the hole as the air cleaner cover will have a fitting and tube leading from the cover to the restriction gauge.

Pierce

Re: Engine air filter / canister question

Reply #11 – May 15, 2021, 08:59:55 pm

Visa via the small holes:

But, the whole outside of the filter element open to the air inlet. How do the two tiny holes figure in, as they are also connected to ambient air, but a tiny, tiny percent of the size of the air inlet?

Guess I need help understanding this.

Re: Engine air filter / canister question

Reply #12 – May 15, 2021, 09:04:42 pm

Two different holes getting confused here.

Brett, you are still talking about the little holes in Lt403's canister.

Bob and Oldguy and Pierce are talking about the hole in the small end metal cap on the air filter.

Re: Engine air filter / canister question

Reply #13 – May 15, 2021, 10:20:29 pm

There is a small hole in the end cap of my filter. I will install it tomorrow and take pics.
I still don't know the purpose of the small hole on the outside of the filter housing.
No one has posted that they have one also.

Re: Engine air filter / canister question

Reply #14 – May 16, 2021, 12:06:08 am

I have never noticed a hole in my canister.

Re: Engine air filter / canister question

Reply #15 – May 16, 2021, 12:33:28 am

So the small hole in the end of the closed end of the filter allows the filter minder to measure the amount of restriction across the filter medium. Check to make sure your old filter had the small hole in the end. Some of these filters will not have a gasket on the closed end, also with no hole. No hole equals no indication of filter being blocked by filter minder. The small brass 90 deg fitting from the filterminder going into the end of the canister has a brass splintered filter in it. They can and do plug up. So when you check your filter minder for proper operation you still have to check to make sure that you CAN draw air thru the small 90 deg fitting in the filter canister end. This vent to small hole to clean side of filter. It may be restricted, but should still allow air to pass. I sprayed mine with brake cleaner and flowed much better.

Please don't forget to replace your vacuator valve in the bottom of the air filter canister. They get old stiff and shrink. New seal and okay to RTV in place. will prevent possible water ingestion also.
Scott

Re: Engine air filter / canister question

Reply #16 – May 16, 2021, 08:12:59 am

Quote from: Chuck & Jeannie – May 15, 2021, 09:04:42 pm

Two different holes getting confused here.

Brett, you are still talking about the little holes in Lt403's canister.

Yes, the small holes in the canister side, not lid. First picture in original post.

Re: Engine air filter / canister question

Reply #17 – May 16, 2021, 08:17:58 am

Quote

The small brass 90 deg fitting from the filterminder going into the end of the canister has a brass splintered filter in it.

What's a "splintered" filter?

Re: Engine air filter / canister question

Reply #18 – May 16, 2021, 08:36:09 am

Quote from: Larry Rubin – May 16, 2021, 08:17:58 am

What's a "splintered" filter?

Just guessing, as I have not removed one, but perhaps: Sintered Bronze Filter.

sintered bronze filter - Google Search

Re: Engine air filter / canister question

Reply #19 – May 16, 2021, 09:32:59 am

OK, a photo is worth a thousand words. You do need the rubber gasket or the filter will not seat correctly and if it had a hole, the unfiltered air would enter through the hole. So, you need both rubber gasket and hole in the filter end if you have a canister end like in the photo. The plastic tube leading to the restriction gauge is not shown in the photo but screws on the 90 degree fitting in the middle of the canister end. If you need a hole in the end of the element, don't drill, just use an ice pick and your hand.

Pierce

Re: Engine air filter / canister question

Reply #20 – May 16, 2021, 09:45:30 am

Quote from: wolfe10 – May 16, 2021, 08:36:09 am

Just guessing, as I have not removed one, but perhaps: Sintered Bronze Filter.

sintered bronze filter - Google Search

Yes

Re: Engine air filter / canister question

Reply #21 – May 16, 2021, 09:47:45 am

I've replaced my vacuator valve when we originally picked up coach, can't find the number for it. Lots of good prior posts on this subject.
Scott

Re: Engine air filter / canister question

Reply #22 – May 16, 2021, 10:07:33 am

Quote from: Pierce & Gaylie Stewart – May 16, 2021, 09:32:59 am

So, you need both rubber gasket and hole in the filter end if you have a canister end like in the photo. The plastic tube leading to the restriction gauge is not shown in the photo but screws on the 90 degree fitting in the middle of the canister end.

What you state is a very important point.

On your '93 U300 the air filter is "standard flow" (outside to inside). The air volume being monitored by the Filter Minder is on the inside of the filter. The hole in the metal filter end allows the restriction gauge to measure the vacuum (if any) inside the filter.

On our '93 U280 the air filter is "reverse flow" (inside to outside). The air volume being monitored by the Filter Minder is on the outside of the filter and inside the filter canister. The tube to my restriction gauge comes off the exit pipe that leads from the canister to the turbo. The air filter I use (AF954M) does have the hole in the small end metal cap, but on my coach it serves no purpose. Since it is inside the rubber end gasket it also does no harm ( IE does not allow unfiltered air into the engine).

PS: If your coach, like mine, has a reverse flow air filter, the air filter canister will not have a vacuator valve. (Just to save you the effort of searching for it)

Re: Engine air filter / canister question

Reply #23 – May 16, 2021, 10:08:47 am

Sorry I missed that picture. I don't think there should be holes there, they don't make any sense.

Re: Engine air filter / canister question

Reply #24 – May 16, 2021, 10:16:13 am

Sintered filter in small fitting

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