Jump to content


EJ25D/EJ251/EJ253 oil pump size

Oil pump ej25 ej25 oil pump EJ25D EJ251 Ej253

  • Please log in to reply
No replies to this topic

#1 El_Freddo


    Rock'n the old Skool

  • Members
  • PipPipPip
  • 1,332 posts
  • Gender:Male
  • Location:Bendigo/Benders/Central Vic/part nomad
  • Interests:Subarus, 4wd'n Subarus, travelling Subarus, Tinkering... I could go on!

Posted 13 February 2018 - 10:23 PM

G'day all,

I'm after anyone who has first hand information on the size of the oil pump in the EJ25D/EJ251/EJ253.

I've read on the usmb that the ej25 runs a factory 8 or 9mm width oil pump gear. I know the EJ22e (Gen1) runs a 10mm wide oil pump gear and I believe this is the same for the ej20 plus the early turbo variants excluding the sti turbo that ran a 12mm width pump gear.

The reason I ask is because in the discussion previously mentioned they talk about how to keep the ej25 from throwing rods. I know there's a process in this occurring - repeated overheating events that cooks the oil that then kills the big ends that then throws the rod out the top. I don't think this was common place in Australia as it seemed to be an issue isolated to the US - I believe this is partly due to the Australian market receiving Japanese build vehicles as opposed to the USDM getting US built units of poorer quality.

So back to the oil pump size - the discussion/advice to keep an ej25 in good condition was to swap the oil pump out for a 10mm unit to keep the bottom end lubricated well. Does this sound legit? I want to know as my sister pumped out 40k km last year in her Gen3 RX "Basil". One thing I really want to avoid is engine work or a replacement engine. The one in there atm runs sweet as it is.

If something "as simple as" swapping out an oil pump to a larger unit will help out it's something I'd like to get on to. I have a suitable oil pump that I'll strip down to clean out and replace O rings etc to place in the EJ251.

I'd like to hear from anyone that's got solid experience in this issue rather than theories. I know keeping oil level where it should be and regular oil changes are key as well. Simply due to kms I'm also considering bumping oil changes to 15k km as the oil gets a good run at cruising speed for about 45 mins morning and afternoon. I'm 99% sure sis doesn't hit it hard like I do at times.


"The lounge room is not a workshop..."
El Freddo's Pics    -    El_Freddo's youtube

Also tagged with one or more of these keywords: Oil pump, ej25, ej25 oil pump, EJ25D, EJ251, Ej253

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users