Oil pump vent??
 

My car has been leaking oil BADLY from the oil pump ever since I rebuilt the engine. I was thinking it may have been a bad oil outlet o-ring and was going to pull the engine again, but on closer inspection I noticed something peculiar when I was pulling my power steering pump... there was a hole on the oil pump housing.

"Hmmmmm" I thought. I then shined my flashlight down the hole. I could see all the way through to the pan. I then unwound a coathanger and shoved it in. Sure enough, it went all the way in and came out dripping with lube. Since I threw out my old oil pump, I could not verify if this hole in the new pump is supposed to be plugged or not. Could somebody check for me pleeeeease??

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The car only leaks oil under load at WOT, and it leaks A LOT. It has sprayed everywhere in my engine bay, and I cannot touch anything in there without getting oil on me.

We couldn't tell.

It should be sealed. Originally it was the dipstick tube hole for the 323 I believe. I think I have silicone in mine, or a JB welded plug, not sure, its from the factory.

Edit: if you're good with cleaning out your engine, looks like you might be able to drill a bit oversized and tap it for an NPT plug. 1/8 or 1/4.

Mazda makes a plug that goes in that hole. If you bought your pump from mazdamotorsports website, they will have included that plug with the oil pump. I'll see if i can get a P/N for it...

mazda part number:
9930-71-000

it looks like it runs $1.38

taps in with a punch and light taps from a hammer.

Best guess, it's the dipstick hole for a front drive oil dipstick. I think if you read on the fwd/rear drive conversion, there's something about having to plug that.....

The above part should fix it though.....

Dave,

I've just used a slightly oversized bolt that I could thread in with a wrench before. Using JB as a sealant.

Awesome thanks guys. I got my pump from NAPA and had to make a pickup tube gasket and find a circular oil outlet o-ring. I didn't realize there was more.

I'm not sure if this is the problem though because whenever I accelerate, my oil pressure goes down. I guess we'll see if plugging this works.

FWIW, the pump I bought from mazdacomp did not include the plug, I had to order it later, separately.

--Ian

+1, my replacement pump did not come with that plug. I used JBweld and a square of aluminum to seal it off. Next time I have it apart (hopefully never) I'll order that plug.

Either a: you've run so low on oil that it runs low around the pickup tube and you get air in there

or b: the pickup tube gasket you 'made' failed, and air is getting into your oil pump that way.

Bump, that plate came off of the pump and oiled down the engine bay at Buttonwillow yesterday. Do as I say, not as I do - get the OEM plug.

Looks like you've got yourself an easy fix.... GO to mazda dealer, order plug...tap in till it's flush.

Spray everything down with brake cleaner, go for a drive...