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Kristoffer Sellebjerg

Low oil pressure on startup, after oil change.

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Hello!

 

1997 986 Boxster 2,5 automatic transmission.

 

Replaced the oil filter ( Brand is Hengst ) and the engine oil with Mobil Super 3000 5w40. Climate is rather cold - located in northern Europe.

 

When starting the engine cold, it will take around 10 seconds for the low oil pressure light to turn off. Revving the engine slightly helps and turns the light off. When engine is warm, the light is out right after engine start. There are no unusual sounds form the engine when the light is on.

 

Oil level is correct.

 

What could cause this? The problem came after the oil change.

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1 hour ago, Kristoffer Sellebjerg said:

Hello!

 

1997 986 Boxster 2,5 automatic transmission.

 

Replaced the oil filter ( Brand is Hengst ) and the engine oil with Mobil Super 3000 5w40. Climate is rather cold - located in northern Europe.

 

When starting the engine cold, it will take around 10 seconds for the low oil pressure light to turn off. Revving the engine slightly helps and turns the light off. When engine is warm, the light is out right after engine start. There are no unusual sounds form the engine when the light is on.

 

Oil level is correct.

 

What could cause this? The problem came after the oil change.

 

I would start by checking the car with a proven mechanical pressure test gauge to make sure it is low pressure and not a failing oil pressure sensor.

 

If the oil pressure is good, you should replace the pressure sensor, and I would also replace the oil pump pressure regulator piston and spring with the updated version Porsche released a couple of years back to address low oil pressure issues.  All in, the pump pressure regulator parts will cost about $20 (US), and it is  very worth while update.

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Thanks for inputs!

 

Will check the actual oil pressure and install the updated pressure regulator parts. Is there a guide for this procedure somewhere here? 

 

Still can't figure out why everything was normal before the oil change though.

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13 minutes ago, Kristoffer Sellebjerg said:

Thanks for inputs!

 

Will check the actual oil pressure and install the updated pressure regulator parts. Is there a guide for this procedure somewhere here? 

 

Still can't figure out why everything was normal before the oil change though.

 

Could just be a coincidence, the only thing I can think out that could crap out during an oil change is the by pass valve in the bottom of the filter cannister, these are very prone to failure but the fix is simple: Buy a new cannister as the valve only comes with it.

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3 minutes ago, Kristoffer Sellebjerg said:

Thanks again! Will definitely replace the oil filter housing as well. 

 

Before I get under the car, where do I have to look to find the oil pressure relief valve?

 

All these parts have been superseded with upgraded pieces:

  • Piston 997.107.125.01 
  • Spring 996.107.127.53
  • Gasket 996.107.123.50

So for less than $20 at retail, you get better low RPM oil pressure.  The new piston also has a bevel on its upper edge as well, and the spring is slightly longer

 

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Perfect, thanks - I really appreciate your help.
 
I will update once the new parts are in place and oil system tested.


To piggyback onto what JFP said, I did this on my '99 3.4 996. However, I gently polished the piston exterior with Jewelers rouge prior to install to gild the lily. Instant idle OP improvement. And mine was actually fine before.

Best $20 you'll spend on the car. Especially for warm ambient temps.


Sent from my iPhone using Tapatalk

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Sounds good! Parts are on the way. Will also replace the oil pressure sender, since it´s cheap and apparently tend to fail over time, as I can read. 

 

As I can see, the easiest way to access the oil pressure sender is from the top - with the engine top cover removed. Is that correct?

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1 hour ago, Kristoffer Sellebjerg said:

Sounds good! Parts are on the way. Will also replace the oil pressure sender, since it´s cheap and apparently tend to fail over time, as I can read. 

 

As I can see, the easiest way to access the oil pressure sender is from the top - with the engine top cover removed. Is that correct?

 

Yes.

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Update:

 

Oil filter cup and oil filter replaced.

 

Oil pressure sender (switch) replaced.

 

Oil pressure control piston, spring and crush washer replaced.

 

All original parts.

 

The problem still persists. Actually the low oil pressure warning light is steady on now when the engine is running. Of course I did not run the engine for more than a few seconds, but everything sounds normal. 

 

I cut the old oil filter open to check for metal debris - looks nice and clean.

 

I do not have an oil pressure tester - but I measured on the oil pressure switch to check the oil pressure. When engine is not running, the switch is closed to ground. Engine started - the switch opens and break the circuit. A few seconds after turning off the engine, the switch closes to ground again. I guess this indicates normal oil pressure - as the operation of the oil pressure switch seems normal?

 

The wire from the switch to the cluster ( White connector, pin no. 6) is fine - i checked that. Could this be a bad cluster issue?

 

 

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5 minutes ago, Kristoffer Sellebjerg said:

Update:

 

Oil filter cup and oil filter replaced.

 

Oil pressure sender (switch) replaced.

 

Oil pressure control piston, spring and crush washer replaced.

 

All original parts.

 

The problem still persists. Actually the low oil pressure warning light is steady on now when the engine is running. Of course I did not run the engine for more than a few seconds, but everything sounds normal. 

 

I cut the old oil filter open to check for metal debris - looks nice and clean.

 

I do not have an oil pressure tester - but I measured on the oil pressure switch to check the oil pressure. When engine is not running, the switch is closed to ground. Engine started - the switch opens and break the circuit. A few seconds after turning off the engine, the switch closes to ground again. I guess this indicates normal oil pressure - as the operation of the oil pressure switch seems normal?

 

The wire from the switch to the cluster ( White connector, pin no. 6) is fine - i checked that. Could this be a bad cluster issue?

 

 

 

I would put a mechanical pressure gauge on it before doing anything else; you need to know what the actual pressure is before doing anything else.

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Got the oil pressure tester today and hooked it up. Oil pressure seems good. 6 bars idle, cold engine. 2,4 bars idle on warm engine.

 

As mentioned the pressure sensor is replaced with no luck. Wire to the cluster seems good.

 

Any suggestions on how to move on from here?

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1 hour ago, Kristoffer Sellebjerg said:

Got the oil pressure tester today and hooked it up. Oil pressure seems good. 6 bars idle, cold engine. 2,4 bars idle on warm engine.

 

As mentioned the pressure sensor is replaced with no luck. Wire to the cluster seems good.

 

Any suggestions on how to move on from here?

 

This is why I suggested checking the pressure with a known mechanical tester before moving foward.  When you say the wire from the sensor to the cluster is good, how did you check it?

 

It is entirely possible the cluster gauge itself is bad.  If it is, I don't know of anyone that repairs individual gauges, so you would be up for replacing the cluster, which is coded to the DME, so you are going to need access to a factory computer ( PIWIS) to complete the replacement.

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Yes - when it comes to oil it is good to be sure. 

 

I checked the wire for continuity with a multimeter, and checked that it is not grounded (Will make the oil light illuminate). Might be worth to try with another piece of wire from the sensor to the pin on the cluster just be sure it is not the wire making the trouble.

 

 

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Just tried to connect a piece of wire directly from the sensor to the cluster. Problem still persist. I guess next step is to get the instrument cluster checked somehow. The local workshop claim that no coding is needed to replace the cluster on a 97 Boxster - except for the milage. Is this true?

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5 minutes ago, Kristoffer Sellebjerg said:

Just tried to connect a piece of wire directly from the sensor to the cluster. Problem still persist. I guess next step is to get the instrument cluster checked somehow. The local workshop claim that no coding is needed to replace the cluster on a 97 Boxster - except for the milage. Is this true?

 

Up to a point, you still need either a PST II or PIWIS unit to set the mileage as long as the odometer mileage on the replacement cluster is less than 30 miles.

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Posted (edited)

Thank you. So a swap will work with no coding. Only needed for setting the milage. Will see if I can find an extra cluster and check if this will fix the oil pressure light issue.

Edited by Kristoffer Sellebjerg

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1 minute ago, Kristoffer Sellebjerg said:

Thank you. So a swap will work with no coding. Only needed for setting the milage. Will see if I can find an extra cluster and check if this will fix the oil pressure light issue.

 

You can temporarily hook up the new cluster just to check the oil pressure before installing it.

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Could the problem conceivably be the result of restricted flow of cold oil upon start up due to a Hengst filter as opposed to a Porsche filter?

Just a thought.

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4 hours ago, wizard said:

Could the problem conceivably be the result of restricted flow of cold oil upon start up due to a Hengst filter as opposed to a Porsche filter?

Just a thought.

 

No.  The factory filter set up has a seperate by pass valve in the bottom of the plastic cannister which would open if the filter was somehow blocked.

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16 hours ago, JFP in PA said:

 

No.  The factory filter set up has a seperate by pass valve in the bottom of the plastic cannister which would open if the filter was somehow blocked.

Ah, OK. Good to know.

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Update: 

 

Problem is solved. It turned out to be a bad instrument cluster that caused the low oil pressure warning light to stay on permanently. Also I had a spoiler fault light on permanently - which was also caused by the cluster.

 

Replaced the old one with a used instrument.

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