Power steering

[porschedavid]

2005 Porsche 996 4s
Just got car out of garage after being stored for 8 months.Checking levels and found no power steering fluid in reservoir.Cant find leak anywhere.Any idea lads

[Van B.]

Could be contained within the boots on the steering rack
Did fluid make it to the ground?

[porschedavid]

Hi
No fluid on the floor

[Van B.]

I say pull the boots loose on the rack. But watch out in case my guess is right

[porschedavid]

Already checked.Dry as bone

[Van B.]

I realize I forgot to ask if you inspected the top of the engine for pooling? My bad. So first things to check would be at the pump. Check for reservoir cracks or attachments loose/ bad o-ring, power steering lines at the pump are secure and free of splitting.

Since fluid can pool on the top of the motor, get your hand or a camera in there. Pulling the alternator is my go-to for quick access large enough to reach in.

[JFP in PA]

About 3/4 of the cars we saw for regular service either had no or extraordinarily little fluid in the steering reservoir the first time they came in. The tank is small, in a very warm place, and in a spot very few owners ever get to, so finding them low on fluid was a pretty common sign of poor maintenence.

[Van B.]

That’s a real interesting bit of experience. I can’t remember the last time I had to add fluid to mine. Ive got lots of experience working on the 996.
I guess to be more accurate, I should say, “I’ve got lots of experience working on one 996.” Lol

[porschedavid]

Thanks
JFP.
Are you saying it can evaporate.

[JFP in PA]

Originally Posted by porschedavid

Thanks
JFP.
Are you saying it can evaporate.

Yes, it seems to.

[Van B.]

Sorry guys, but I just don’t buy it. Much more likely that it’s leaking down.
There is ample room for fluid to pool on the top of the short block and none of it would ever hit the ground.

[JFP in PA]

Then provide an explanation to how all the ones we have seen short on fluid, not one of them had traces of fluid anywhere on top of the engine or underneath the cars. Just dry dust, no fluid….. Did Scotty beam it up?

[Van B.]

Originally Posted by JFP in PA

Then provide an explanation to how all the ones we have seen short on fluid, not one of them had traces of fluid anywhere on top of the engine or underneath the cars. Just dry dust, no fluid….. Did Scotty beam it up?

Lol, YES! That’s exactly what happened!

Pentosin 11S has a service range from -40F to +266F. So, evaporation is just not likely unless it was being cooked off as it leaked. So for me, there must be a leak somewhere. Evaporation would run contrary to the tens of thousands of cars running 11S that have fluid year after year. Mine included… and I’ve only ever changed fluid because I got concerned about how old the fluid was after being in there for years. Further, disuse would make evaporation less likely, not more likely. Higher temperatures would make evaporation more rapid.


In my sample group of one car over 9yrs of ownership, I had to change reservoir o-rings once because they started to weep. That’s a leak, even if it’s slow and doesn’t leave drips.

In the case of a car that sits far more than it moves, you can dry out of rubber hoses and seals, contraction of fittings, and unmonitored fluid levels.

JFP, I’m sure you’ve become a bit jaded in your years in the business and on this forum… and you’re from PA so, I know you won’t avoid a good argument lol. So, I want you to understand your observations are appreciated and valid in my opinion. But I’m going to insist that there’s a leak, even if the end result looks like evaporation.

And as for the OP, fill it up, drive the car, monitor for leaks, and either take better care of it or sell it.

Van

[JFP in PA]

You might think the loss is all from leaks, but we know it isn’t. First of all, with these engines coolant running in the low 200’s F, the fluid is always near the upper end of its published service temp range because the pump and tank is in a very hot location, which is why a lot of people discover how quick the pumps die when you put the cars on the track for any period of time. Several aftermarket companies sell power steering fluid coolers to try and extend the pump’s life for any serious track rat. So overheated fluid is a real issue with these cars.

Second, we were curious enough to run some experiments to see if there really was leaks somewhere. First thing we did was to add a UV dye to multiple cars which were then monitored over time (the slightest leak of hydraulic fluid with UV dye lights up like Christmas). Nothing showed up. Then we took two cars that regularly had fluid level loss and rigged up a pressure testing rig that put 150 PSIG on the system and let them sit for hours. The pressure did not drop.

So I’ll ask again: If it isn’t evaporating, where is it going?

[Van B.]

I think more to the point is why don’t all 996/997s have this problem? They all use the same fluid and run at the same temps.

Your story is wild and I believe every word of it by the way!

[Van B.]

Ok, I just looked up the SDS on Pentosin 11S:

Flash Point - >302F (so that’s a no go)
Evaporation Rate - Not Determined (not helpful)
Miscibility in Water - Fully Miscible

That last data point is significant for the evaporation theory. If enough water were absorbed over time, and since it will remain in solution, then evaporation could/would likely occur even under normal operations. And if exposed to air, would occur during storage.

I think, I’ll remain skeptical regarding the likelihood or commonality of this occurring. But, it seems a worn o-ring on the filler cap would be enough to begin the process over a long enough period of time or under extreme temperatures.

Thanks for sharing the stories JFP!

Van