Low humming noise from Air Filter. Rocker Arm?

Does your Mitsubishi L300 make a strange noise? Need wheel alignment specs?
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VanderBosch
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Low humming noise from Air Filter. Rocker Arm?

Post by VanderBosch » Mon Jun 25, 2018 5:17 pm

Hello!

After many months of trying to figure out what to do with my cracked block, I decided to take a leap of faith and try JB welding it. After about a month of driving I haven't seen any leaks! :-D

Since I've been driving it more often (now that its not spraying coolant everywhere), I noticed a weird low humming sound and it seems like its coming from the air filter?

From previous threads, I've read that a low humming noise (almost like a muffler noise) coming from the air filter may be due to a bad rocker arm. I think I have the gasket for the valve cover but what else is required to replace a broken rocker arm? Is the job difficult? Where did you get your new rocker arms?

Any info would be greatly appreciated! I'm hoping to tackle this one on my own!

Thanks again!

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ChuckBlack
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Low humming noise from Air Filter. Rocker Arm?

Post by ChuckBlack » Mon Jun 25, 2018 10:52 pm

First of all,
Have you checked all hose connections, clamps, air filter clips and air filter seal??
Have you removed the R.A. cover? If so, rock each rockers individually, check for excessive side/up,down pay. Check for missing or loose mounting bolts. If you need a new rocker, you can order parts from various RHD shop around.
Rising Sun Imports,
Coombs Country Auto
JDM Connections
Partsouq.com

Cheers..

P.S. check your ash tray! You can get a humming noise when they are fully closed! Mine does it when I carry less than 15cent, so I pull on the tray just a bit and it all goes away!
L300 Jasper, :-D
L300 Chamonix, :-)
Pajero Mini, :-(
Pajero GDI :o
Pajero DiD 8-)

VanderBosch
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Low humming noise from Air Filter. Rocker Arm?

Post by VanderBosch » Wed Jun 27, 2018 4:54 pm

So...

I removed the rocker arm cover following this thread viewtopic.php?f=6&t=6707&hilit=rocker+cover

It looked like the previous person used sealant goo all around the cover, some of the sealant was sitting inside the cover. I played with the rockers and they seem stable, the ones that are higher can be slightly moved from side to side. The ones that are compressing the spring (sit lower) can not be moved from side to side.

I guess I really don't know what I'm looking for in terms of a broken rocker arm. I don't see any metal shavings.

I did put some fuel system cleaner in my last tank but I don't know why that would cause that low muffler humming noise from the air filter. When I put a piece of paper next to the filter inlet, it seems like air is blowing out instead of in? I have seen an extra bit of power though after putting the fuel system cleaner in.

I took off the drivers seat and it looks like there might be a missing air pipe? From the filter a section of pipe follows the outside edge of the van and then there's a gap and another section of pipe toward the inside of the van. Doesn't look like there have been a connection between these two sections in a very long time.

Any other tips would be greatly appreciated!

Thanks again!

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Growlerbearnz
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Low humming noise from Air Filter. Rocker Arm?

Post by Growlerbearnz » Wed Jun 27, 2018 7:09 pm

The hose between the fresh air duct and air filter intake is supposed to be missing (http://www.delica.ca/forum/viewtopic.php?f=102&t=18386).

Could you make a video of the noise and upload it to Youtube? I'm having trouble imagining a humming noise coming from the intake. Chuffing or farting noise: air leak, either loose hose clamp or a split in a rubber hose (air intake to steel pipe, or steel pipe to turbo).
Nothing says "poor workmanship" more than wrinkles in the duct tape.

VanderBosch
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Low humming noise from Air Filter. Rocker Arm?

Post by VanderBosch » Wed Jun 27, 2018 7:28 pm

I'll try and get a video tomorrow!

VanderBosch
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Low humming noise from Air Filter. Rocker Arm?

Post by VanderBosch » Thu Jun 28, 2018 10:56 am

Before I put the Rocker Arm Cover back on and get that video to you, is there a way to turn over the engine without starting it? I was hoping that might reveal a problem with the rocker arms (if one exists).

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Growlerbearnz
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Low humming noise from Air Filter. Rocker Arm?

Post by Growlerbearnz » Thu Jun 28, 2018 2:44 pm

When setting rocker clearances, I use the starter. Just a quick bump of the key turns the engine just a little. Unplug the two connnectors on top of the injection pump first, and then the engine won't start.
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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