Low Oil Pressure

etcwhitlock · 10-23-2016, 03:56 PM

I have tried to search the forums, but cannot find anything directly related -

I start the car, and get 4-5 on the oil pressure gage. After the car warms up, the pressure starts to fall off, so that it finally settles at 2-3 on the gage when at full speed. At idle, it is less than 1 on the gage, and the oil light comes on, unless i give it a little gas to bump it up.

Not sure what the problem is, since I have no oil leak that I can determine.

Any ideas? And please, do not tell me to take it to the dealer to have it checked out.

Thanks!

Ed

Jeff Alton · 10-23-2016, 10:11 PM

What vehicle?

M. Murphy · M. Murphy's Garage

Sounds like a 944 to me.

etcwhitlock · 10-25-2016, 09:17 PM

Sorry that i forgot to put the car info. It is a 1999 Boxster 986. 2.5liter manual transmission.

thanks again.

Ed

M. Murphy · M. Murphy's Garage

I'm new to the Boxster (1998 base). Is this being read with an external or aftermarket oil pressure gage? I think all I have is an idiot light. Is there an electronic oil pressure display I'm unaware of?

mikefocke · 10-26-2016, 04:35 PM

Quote:

Originally Posted by M. Murphy

I'm new to the Boxster (1998 base). Is this being read with an external or aftermarket oil pressure gage? I think all I have is an idiot light. Is there an electronic oil pressure display I'm unaware of?

Not unless someone put a 996 cluster into the car.

etcwhitlock · 10-26-2016, 06:11 PM

Yes, i put a 996 cluster into the car. Did the modification from the tech article here.

I installed the 996 oil sender and I get the red warning light when the car idles halfway between the 0 and 1.

It seems that I only have low oil pressure when the engine is hot, not cold.

Ed

DCinVA · 10-27-2016, 06:52 AM

I would start by changing the oil and filter, and assure you are using the correct weight oil.
If that does not fix it, you will need to determine if the issue is engine related or electronics related.
Find a mechanical pressure gauge and plumb it into the sending unit opening. Run the engine with the mechanical gauge attached to confirm you do indeed have low pressure. If indeed the pressure is that low, that could indicate a mechanical issue with the engine. If the mechanical gauge reads OK then start checking the sending unit, and the gauge.

Hopefully the problem is a simple one.

etcwhitlock · 10-27-2016, 02:45 PM

I changed the oil and filter last weekend, with no change in pressure. I installed the new oil sender unit when I did the cluster upgrade, but I was getting the oil pressure light long before I changed it out.

mikefocke · 10-27-2016, 06:36 PM

Any lights or CELs with the original cluster? How do you know that the oil pressure reading wasn't the reason the cluster was offered for sale?

JFP in PA · 10-28-2016, 05:44 AM

Quote:

Originally Posted by etcwhitlock

I changed the oil and filter last weekend, with no change in pressure. I installed the new oil sender unit when I did the cluster upgrade, but I was getting the oil pressure light long before I changed it out.

You need to pull the pressure sensor and temporarily install a good mechanical gauge to check the actual pressure. That is the only way you are going to know if it is a mechanical problem, or something wrong with the cluster/sender.

etcwhitlock · 10-28-2016, 02:43 PM

Quote:

Originally Posted by mikefocke

Any lights or CELs with the original cluster? How do you know that the oil pressure reading wasn't the reason the cluster was offered for sale?

I was getting the oil light when at idle with my last instrument panel.

etcwhitlock · 10-28-2016, 02:44 PM

Quote:

Originally Posted by JFP in PA

You need to pull the pressure sensor and temporarily install a good mechanical gauge to check the actual pressure. That is the only way you are going to know if it is a mechanical problem, or something wrong with the cluster/sender.

I am going to do that this weekend. If mechanical, can I replace the oil pump with the engine in the car? Is there a diy on this?

JFP in PA · 10-28-2016, 03:24 PM

Quote:

Originally Posted by etcwhitlock

I am going to do that this weekend. If mechanical, can I replace the oil pump with the engine in the car? Is there a diy on this?

The oil pump is in an external cassette next to the water pump. Would suggest getting access to the OEM service manuals for the how to as there are a few things in the way, and you would want to replace the oil pump drive shaft (an investment cast unit prone to failure with the $20 LN Engineering chrome moly unit).

DCinVA · 10-29-2016, 02:41 AM

What brand and weight oil are you using?
Using oil that is not the correct viscosity can cause low pressure.

Just trying to eliminate the simple things before tearing into the engine!

etcwhitlock · 11-14-2016, 07:17 PM

Quote:

Originally Posted by JFP in PA

The oil pump is in an external cassette next to the water pump. Would suggest getting access to the OEM service manuals for the how to as there are a few things in the way, and you would want to replace the oil pump drive shaft (an investment cast unit prone to failure with the $20 LN Engineering chrome moly unit).

OK, bought the Bentley service manual for the 986. Went to the Lubrication Section, and all it tells you is how to replace the oil cooler. Nothing in the thing tells you how to replace the oil pump! It just mentions that there is an oil pump in the engine! Ugh! How do you replace the oil pump? I have one, just want to make sure that I don't mess anything up!

JFP in PA · 11-15-2016, 03:22 AM

The Bentley, while a decent manual, is not comprehensive. You need the factory service manuals.

DCinVA · 11-15-2016, 04:14 AM

Take a look in PET to see what it looks like.

http://www.porsche.com/all/media/pdf/originalparts/usa/986_USA_KATALOG.pdf

etcwhitlock · 11-15-2016, 05:39 PM

Quote:

Originally Posted by etcwhitlock

OK, bought the Bentley service manual for the 986. Went to the Lubrication Section, and all it tells you is how to replace the oil cooler. Nothing in the thing tells you how to replace the oil pump! It just mentions that there is an oil pump in the engine! Ugh! How do you replace the oil pump? I have one, just want to make sure that I don't mess anything up!

OK, well I found a factory Service Manual for sale. hope this is what I need.

Thanks!

etcwhitlock · 12-01-2016, 01:42 PM

Quote:

Originally Posted by JFP in PA

You need to pull the pressure sensor and temporarily install a good mechanical gauge to check the actual pressure. That is the only way you are going to know if it is a mechanical problem, or something wrong with the cluster/sender.

what is a good oil pressure? i am getting 10psi with the car warm.