Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Oil pressure: How low is too low?


  • Please log in to reply
15 replies to this topic

#1 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 05 April 2005 - 11:29 PM

Just installed a mechanical oil pressure gauge in my ea81t. I've done a search on this, but didn't come up with what i wanted.

Once the oil is up to temp, it sits at around 10psi at idle, and around 35psi at 2500rpm.
I know this is lower than the specified pressure, but does anyone know if its too low for the hydraulic lifters to function?

#2 torxxx

torxxx

    I void warranties

  • Members
  • 2,914 posts
  • Fairbanks

Posted 06 April 2005 - 01:06 AM

yes you will notice some TOD from that low of oil pressure.. if it does, try some 15w-40

#3 Snowman

Snowman

    Midnight Passenger

  • Members
  • 3,538 posts
  • Haines

Posted 06 April 2005 - 01:25 AM

The general rule that I have heard from a lot of reliable sources is around 10psi per 1000 rpm. Although your oil pressure is not stellar, I don't think it's low enough to cause problems.

#4 torxxx

torxxx

    I void warranties

  • Members
  • 2,914 posts
  • Fairbanks

Posted 06 April 2005 - 02:38 AM

If it was N/A I'd say it would be fine, but since its a turbo they get ran harder and they run hotter. I'd want at least 20psi at an idle and probably 45 or 50 at 2500.

#5 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 06 April 2005 - 02:42 AM

Thanks guys.
i have a spare oil pump sitting around, so i might give that a check and put it on. Better safe than sorry, ay.

#6 555Ron

555Ron

    USMB is life!

  • Members
  • 199 posts
  • Newcastle, Aus

Posted 06 April 2005 - 06:43 AM

*hijack*Hi Ross,
How/where do you use/get an oil pressure tester? Does it sit under the bonnet, or do you attach/detach it when you want to take a reading?
*/hijack* ... apologies for the hijacking.

#7 archemitis

archemitis

    guy smiley

  • Members
  • 3,554 posts
  • the big minnie

Posted 06 April 2005 - 12:41 PM

dont trust mechanical gauges, just because they are new. mine is 10 lbs off.

it takes 4 lbs of pressure to pump up lifters. if you arent ticking like mad, your pressure is fine.

#8 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 06 April 2005 - 05:24 PM

*hijack*Hi Ross,
How/where do you use/get an oil pressure tester? Does it sit under the bonnet, or do you attach/detach it when you want to take a reading?
*/hijack* ... apologies for the hijacking.


No worries..

Buy them at any auto parts store. If you get a mechanical one, tey come with gauge, hose, and fittings.
These fittings fit into where your factory oil pressure sender/oil pressure switch goes into (on oil pump on ea81s).
There is also a spare port that you can use on the ea81 oil pump so you can keep your oil light and turbo line (if its a turbo).
You then mount the gauge in your car.

#9 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 06 April 2005 - 05:27 PM

if you arent ticking like mad, your pressure is fine.


It is ticking like mad. Im gonna swap in a good oil pump today, just to rule that out before i start getting more drastic, or decide to just ignore the ticking.
A more worrying noise i'd like to remove is a faint knocking at idle. Im hoping a little more oil pressure will fix it.

#10 erik litchy

erik litchy

    Leadfoot

  • Members
  • 1,090 posts
  • Peoria IL

Posted 06 April 2005 - 05:33 PM

No worries..

Buy them at any auto parts store. If you get a mechanical one, tey come with gauge, hose, and fittings.
These fittings fit into where your factory oil pressure sender/oil pressure switch goes into (on oil pump on ea81s).
There is also a spare port that you can use on the ea81 oil pump so you can keep your oil light and turbo line (if its a turbo).
You then mount the gauge in your car.


they look like this
Posted Image

#11 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 06 April 2005 - 07:21 PM

Some more info on the problem:
Running 10w40 mobil synthetic oil + subaru filter.
Oil pressure 70psi at 2000rpm with engine cold.
Drops to 8-10psi @ idle, 30-35psi @ 2500rpm.
Develops TOD and light knock when idling when engine fully warmed up.

My other oil pump is no good, so the other option is to buy a new one for NZ$120. (I'd prefer to be able to do a quick swap ratehr than take the other one off and re seal it, especially if its beyond repair.)

Any more opinions on whether this oil pressure is too low/whether i should get the new pump?

Cheers.

#12 erik litchy

erik litchy

    Leadfoot

  • Members
  • 1,090 posts
  • Peoria IL

Posted 06 April 2005 - 07:56 PM

bad oil pressure can wear the cam and crank bearings making the problem even worse.

id like to see at least 1 bar at idle. if you get the new oil pump you at least get the peace of mind that its no longer a problem.

#13 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 08 April 2005 - 05:06 PM

Well, got the new oil pump and put it on yesturday.
No change in the oil pressure. :banghead:

The old pump looked like it had been replaced resonably recently. Thats ok though, at least i have a good one for my other ea81.

So, im thinking it must be worn bearings.
Is there something else that could be causing this?

Its around 5-15 deg. celcius here at the moment, so i dont think my 10w40 is too thin or anything.

#14 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 09 April 2005 - 05:34 PM

Anyone think I should check the oil strainer?

There is a lot of grime in this engine, so it may be blocked.

#15 Ross

Ross

    Can't be bothered

  • Members
  • 1,865 posts
  • Christchurch, New Zealand

Posted 10 April 2005 - 12:28 AM

Oh dear...... just took the wagon for the first long drive since i put the oil pressure gauge on..... after a while the pressure was sitting below 20psi at 2500-3000rpm.
I think i might want to stop driving it till i get this sorted.

#16 BlueTrain

BlueTrain

    Subaru Fanatic!

  • Members
  • 477 posts
  • MisSOULa

Posted 10 April 2005 - 12:41 AM

Oh dear...... just took the wagon for the first long drive since i put the oil pressure gauge on..... after a while the pressure was sitting below 20psi at 2500-3000rpm.
I think i might want to stop driving it till i get this sorted.


ya, below 20 @2500-3000 is rather low.. Snowman was right when he said at least 10 per 1000 rpm...my EA82 idles at about 5-10 @ idle, but runs 30-35 @3000rpm when warm..




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users