Low Oil Pressure At Idle
 

Low Oil Pressure At Idle ? Is there any way to increase idle oil pressure ?Can the gears in the oil pump be replaced. Is the only recourse to replace the motor.Oil pressure off idle is fine . Only when stopped with hot motor will oil light blink.Motor runs great.No noise.

How many miles on the engine? Oil pumps almost never wear out. Bearings do and there are a whole lot of bearings in these engines. And past experience on other engines has taught me that low oil pressure at idle indicates a worn engine.

Sorry. I think you need a replacement. Or just live with the low oil pressure for a while--it could last for years.

I agree with the wear, so. Aluminium oil pump housing running hardened steel gears. Low pressure is only at idle as soon as rpm increase so dose pressure. So why couldn't it
be the pump walls are slightly wore. At low rpm pressure is lost between gears and pump wall ?I cant believe no one has tried to re build or replace the pump . If it had low pressure across the entire rpm range then yes rod and main bearings shot.Or knocking rods .

Can't agree. These engine's are known for weak or weakening oil pump oil pressure relief valve springs, Porsche even released an update kit with a spring and updated piston to address the problem, retail cost around $20 and 5 min. DIY to change.

Before thinking about replacement engines, I would:


1. First check the actual oil pressure with a known gauge, you wouldn't be the first with a bad sender.
2. Get the updated parts and install them.

Gabe, are you using 0-40W oil? since you live in Houston you may want to try 5-40W next time to see if it helps with the low pressure at idle..?

Thank you guys I am using 5w40 royal purple.Porsche was not happy with my chose.I have seen the updated spring and plunger . My only concern is the new piston has a chamfer on one end . I would assume the chamfer edge face down.but dont know for sure? You guys and this forum rock..!

I just had this problem last summer. See post below. Not saying that is your problem and I'm sure there are other things that the cause low oil pressure like worn bearings etc...

http://986forum.com/forums/boxster-racing-forum/67743-accusump-install-2.html

For me, it ended up being a valve spring that broke, taking out the hydraulic lifter and valve keeper debris being swallowed through the bank 2 scavenge pump and main oil pump. This in turn damaged the oil pump gears and aluminum pump cassette walls. So the moral of the story for me was that I tried different oils, installed the upgraded pressure relief piston and spring etc... to no avail, until I dropped the oil sump to discover the debris. The oil pump and cassette are about $500 and probably a PIA to replace with the engine in...

http://986forum.com/forums/uploads02...1515668412.jpg

First thing I did when the indicator light blinked at me was drop the pan.I thought the pick up was clogged . No clog or debris found. I added a 2 quart sump and changed from 0-w40 to 5w-40 . Maybe the thicker oil is hard to pick up at low RPM ?I ordered the spring and piston, a new sending unit for a 996 ,and a separate oil pressure gauge .I will put the bypass and gauge in soon .It would take little wear to lose oil pressure between the oil pump gears and walls of the pump at idle.I wonder why you cant get the gears.My 72 AMC jeep's 401 V8 had the oil pump in the timing chain cover .And a rebuild kit was available.

Have you checked vacuum at the oil cap. This could be caused by a failing AOS. According to Dr. Raby there are two failure modes for the AOS. It can fail in a condition that pulls oil from the oil pump pickup, sometimes accompanied by a high pitch squeal from main seal(s). Since max vacuum occurs at idle it's a possibility.

See discussion attached http://986forum.com/forums/performance-technical-chat/21752-looks-like-aos-but-engine-woes.html

Cap can be removed easily ,when removed car runs bad .Put cap back runs ok again.

The oil pump pressure relief valve can be damaged or have debris stuck in it. That would be consistent with the symptoms. When the oil flow is low the leakage through the valve would be significant enough to lower the pressure. At higher RPM, and thus higher flow rates, the leakage would be insignificant enough to not affect the pressure.

amazing this has to be raised given the seemingly decent technical knowledge here, but a 5w-40 and a 0w-40 are the same weight when the car is at operating temperature (setting aside slight cst differences between brands).

The number before the w is the COLD viscosity.

Bypass spring
 

Can the bypass spring be replaced with oil in motor ? Thank you all so very much..!

Yes. There is only a few ounces that will drain.

A Porsche mechanic asks if I have replaced my I.M.S. bearing I say no . He says that can cause low oil pressure at idle. How is that possible when the bearing is not fed oil from the pump ?

You need a new mechanic.........................

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Really? Once again the IMS is blamed for everything from a burnt out tail light to a flat tire. I think at some point climate change will be blamed on a bad IMS.

Put in the updated spring and piston .Put a mechanical gauge on it today 10 psi when motor is hot with 5w-40 oil. What would be the thickest oil I could run .Live in the south west.

I use 15w-50 Mobil 1 synthetic in my 2003 in the Los Angeles area. I buy from Wal-Mart ordered from their web site delivered to my door. Free 2 day shipping on orders of $50 or more. 2 5 quart bottles will get you free shipping. You need 8.5 quarts so you need to buy 2

This is what you should use in a warm climate.

Sounds a little low to me but isn't the pressure switch set at 7 psi?
If it were me, I would try a heavier oil, Mobil 1 5W50 or 15W50. 5W50 is Porsche approved in our cars. You'll most likely get a couple (2-3 psi) more at hot idle. How about the oil filter? What is your setup? Stock or aftermarket?

Walmart has Mobil 1 15W50 on special for $27 for 5 quarts.

I have no idea what the sending unit is set at . Its one for a 996 has the warning light and pressure gauge. The electric gauge is not connected yet . For an air cleaner I'm using a cold air kit, Borla exhaust.Thank you all, you guys have been a great help . I have had the car for a little over a year so I think my biggest problem is I probably used oil that is to light from the start . I had no idea what was used in the car. Started with 0w-40...then 5w-40....Now was thinking 15w-50......What would you all think about a 60 weight oil ..?

I think that if you need anything more than a quality 5W-40, something is wrong with your engine.

JFP, are you refering to exesive bearing clearance or a worn oil pump?

It could be either. What is lacking here is proper "hands on" system diagnostics. If the OP has not done the oil pump piston and spring update, which was introduced specifically to address this issue, he needs to do so. If that doesn't raise the oil pressure, he needs to pull the oil pump cassette and examine the gears for pitting or excessive wear. If there is nothing wrong in the pump, the engine has become "loose", and is leaking the oil pressure internally, which requires a rebuild/replacement. But the ONLY way to know what is going on is to start looking........

I am sorry for hijacking this tread, but does the piston and spring update applies to the 3.4 987 as well..? Thanks!

You would have to check that with a good part department; at some point, the retrofit parts became the parts in the car from the factory, but that would require checking the VIN number to be sure.

Thank you JFP!

I will ask Luke at Sunset

JFP Can the oil pump be removed with the motor in the car ? I did do the oil pump bypass with updated spring and plunger .Thanks for your help sir..!

Yes, and as the cassette shares the metal gasket with the water pump, it is a good time to replace the water pump and the oil pump drive shaft which is an investment cast piece of crap that is known to snap. LN has a chrome moly replacement for about $20.

About to replace the valve/spring on mine. After installing is it recommended to "prime" the engine before starting to build oil pressure? Or is it ok to start immediately after install?

Gents,

Is there torque value reference anywhere for the oil pump pressure relief spring and piston retaining plug.....it much like a drain plug with a crush ring.

I am just changing the 986 stocker to the updated spring (996) and piston (997)...yes late to the party.

I can post an image if the item the part(s) I am referring to are not clear.

Yep the bolt/cap should be torqued to 18ft/lbs (or 25Nm)

okay thanks very much....I found a Rennlist post with a value much higher....probably mapped from the stock oil pan drain which is 37 FTBS - 50 Nm. I have not had the stock pan and plug for many years and this seems high to me.

Where the heck is this documented..

When I installed my oil pressure gauge I did some research on what the oil pressure should be, the discussion is posted in this thread.
http://986forum.com/forums/performance-technical-chat/81566-what-oil-pressure-supposed.html
Supposedly the pressure light comes on at 7 psi so you should be OK at 10 psi.

I just completed this modification and tested it. I would highly recommend after testing oil pressure light "out times" and looking at the old piston definately looks like it had been catching/rubbing on the top/leading edge of the piston. A truely awful design.

My research indicated that 50 Nm was the correct torque value.

With the car level alot of oil will drain out so don't walk away and do something else like I did.....So in having to reset the oil level I discovered that one bar above minimum on the dash gauge gives a midlevel reading on the dip stick. This was completely cold and drained as one can be. It looks like the shops I have used in the past have been overfilling the oil.

Edit: It looks like I have used that one bar with some garden driving. Will have to reset again..may try two bars above min. What does this lower level philosophy do yo this ims bearing if anything

Hats off to those able to do this in the car. Maybe a lift gives better perspective. It is tight up in there. Next time I have the firewall cover off I will look at ....but wow!