Hi guys,

I had a very disappointing call with my trusted shop that the car's engine will need to be torn to access the oil pump and see what the issue is. They don't have time to do the work but say that it is going to take 25-30 hours of labor just to see what is going on with the oil pressure. Given how expensive and time consuming this will be, I would really appreciate everyone's advise...

Background: I have been noticing that when the car is warm, after deceleration and usually when the clutch is depressed, the rpm's will drop below idle and I will get a Low Oil Pressure light. The light will go away immediately and the rpm's will stabilize at idle. This will happen a few times when the car is very warm.

I took the car into my shop to take a look at it along with a boost leak, and they told me that it was being caused by the boost leak and would go away as soon as that was was fixed. Well, they fixed the leak but didn't check if the warning / idle issue was fixed (it wasn't) and just gave the car back to me.

Fast forward 2 weeks: all of a sudden I am making zero boost. The boost gauge is reading as usual although the car was not making any power and it is clear that there is another massive boost leak. I take the car back into the shop and they replace my diverter valves and the car is making normal boost. No real problem so far.

***Here is where things get bad*** The shop says that they can't diagnose the oil pressure issue and have tried everything they can without actually getting to the oil pump. They say that the oil pressure is lower than normal not just at idle. I can ask them for the numbers as I do not remember them off hand.

Another issue is that one of my turbos is running a lot hotter than it should. And they say this is due to it not getting enough oil from the oil pump. This turbo will apparently need to be rebuilt or replaced (might as well go K16 billets).

So as I mentioned earlier, the proposed solution is to have a knowledgable shop tear down to the oil pump and see if any lines are clogged or if the pump itself needs to be replaced (~$1,400 part). So this going to cost me ~6k+ if I go down this route.

Has anyone had anything similar or can you offer me any help? I really want to make sure this is the right move before authorizing any work on the car. If you need more info from me please let me know and I will call the shop to get it.

Thanks in advance!

Justin

 

Justin,

How well does your shop know Porsches? Do you feel 100% confident you can trust their diagnosis? With what they are proposing, I would consider another highly rated Porsche specialist shop for a second opinion before proceeding, unless you feel they are so highly qualified, there is no question about their diagnosis.

 

john i was thinking the oil pressure sensor but the turbo he mentioned has me thinking it might be deeper into the motor

 

I thought that at first, but that's usually intermittent. And he is only getting the light when the RPM's fall real low, which indicates if the RPM's were not falling low, the light would never be coming on. The low RPM could be something unrelated to the oil pump. So the question I would have is "how low were the readings they measured at higher RPM's?" If they are not far off of normal, I would look further for the cause of the low idle before opening the engine.

 

Thanks for the quick responses guys. I am very inclined to get a second opinion on this as we are talking about a considerable spend here. I am also concerned that the idle dip has not been addressed at all by the shop.

Any ideas on why my idle is doing this? I would think a potential vacuum leak but I am not too familiar with Porsche's to say...

 

My initial impression on your "Trusted shop" is not very good.
Are they a reputable shop that specializes in Porsche's, or just a "good shop"?

They stated that your idle drop was due to a boost leak. If they really fixed the boost leak and the idle is still dropping, do they have an explanation?

I'm with John. You really need to be confident the low oil pressure is not just because the RPM's are dropping too far for the oil pump to keep working properly.

At Bay Area shop rates, 30 hours of labor is ~$4500. With that much $$ on the line, I'd recommend you spend a little more $$ and find a specialist Porsche shop that can confirm the diagnosis. Then you can decide if you want your "trusted shop" or the specialist to do the work.

Either way, good luck!!!

 

Oil analysis time perhaps? Blackstone might be able to give some insight?

 

If only one turbo is overheating, maybe you have a failed cat that is clogging up flow?

 

Do you have a lightweight flywheel?

 

I'd like to know how they are measuring this "turbo overheating" and can you relay the test and metrics that go along with that?

 

this could be as simple as a combination vac leak and bad oil sender. further muddling the issue, since it's two distinctly separate things going on, that would cause ALL those symptoms, albeit intermittently. if bad sender, intermittently is the beginning!

you need a second PRO opinion, stat.

 

If the rpm is dropping lower than it should, and then you get low oil pressure, that sounds like a bearing that's spun or going. I'd drain the oil and check for debris. Either way, I wouldn't drive it another mile. 6k could turn into a new motor real quick if you drop to zero

 

what is the RPM dipping to when clutch is pushed in?
Has the N75 valve been checked/replaced?
Oil pressure sender good/replaced?
Oil filter canister little o-ring good? Oil pressure relief spring ok?
What oil do you run?
Has a throttle-body calibration been done?

 

I was going to say what vg said. Had the same issue on a n/a 996 engine. The oil pressure was rpm dependent. As in at idle there wouldn't be pressure but, when you accelerate the pressure rises. Tore the motor down and all he bearings on the crank were toast.

 

how many miles are on it?
what kind of oil are you running?

if you are going to open the engine up for an oil pump, then you might as well do a full rebuild.