rkellison

I have not been on the forus in some time. Finished the rebuild of my 99 996 last year ans my son has thououghly enjoyed it. I just purchased a project 2002 996TT. Right now it is various stages of rebuild. Unlike the 99, this one has a good strong engine and needs cosmetic and electrical work. Enough of the story. I have a problem that has me stuck. I replaced the PS pump because it had overheated and was basically fried. I put in the new one and them left the engine for interior work. Well, I came back to the engine after replacing a bursted fuel line in the tank at the pump. The TT starts up fine and purrs like a kitten. In a few minutes I hear a shrill noise and isolated it to the PS Pump. After a few more minutes the pump gets louder and real HOT! I read the posts about the resevior and I have not replaced it but none of the posts describe overheating of the pump.

I am open to any ideas, comments, etc..

ps.. No pictures yet waiting for all the parts to get put back together.

Macster

The shrill noise -- high pitched squeal like sound? -- sounds like, errr reads like the noise my Turbo made when what proved to be a valve in the power steering tank was acting up.

But, the noise was only present after the power steering fluid and in fact the engine and drivetrain was hot, fully up to temperature.

And AFAIK the pump did not get hot, exceptionally hot.

Now the pump probably runs pretty warm even when everything's fine so are you sure the pump is overheating or you mistaking its normally elevated temperature for overheating?

If you want start up the dead cold engine and let it idle a while.

Then shut off the engine.

Carefully feel the power steering pump, lines, the rack, for presence of or absence of heat.

What you are looking for is all the components that make up the power steering hydraulic circuit/system have what feels like reasonable temperature, a consistent temperature.

What you are looking for is the exception, a component, say a line, that is markedly cooler than than it should be.

My thinking is if there is something wrong there is some line blockage or sticky valve that is acting up that is overheating the fluid or causing the pump to work extra hard which overheats the fluid and the pump.

rkellison

Sounds like a good approach. It will take me a day or two to get back at it. Tonight I replaced the rubber "U" hose in the fuel tank on the pump. It ran about 30 seconds before I lost pressure, The high pressure hose that I added was good enough to blow out the other black rubber hose on the pump. I should have known better and replaced both of them at the same time. On well, live and learn but it is an easy fix.

What is the TSB on the PS Tank about? I replaced the pump and looked over the tank while I had it out and it looks like a tank. Nothing complicated or special.

"02996ttx50

if i'm not mistaken the tsb 4897 iirc(?) is about the faulty valve that causes the "whistling" per macsters post. the prescribed fix from porsche was to replace the entire ps reservoir. i honestly can't say or remember if the pump itself got replaced under that, but i don't think so. yours also, does sound like it might be the pump squealing from lack of lube. as opposed the the known "valve" whine. but i know nothing of its mechanics. sorry.

however, if you engage the clutch and the shrill "whistle or "whine" stops, it is in all probability, the valve resonating inside the reservoir. i must be as has been said at OP temp or even HOT for the condition to occur. as i remember this issue, it was more of an annoyance than something about to fail mechanically, but it was covered under warranty so i replaced it.

rkellison

I read that on some of the other posts about this problem. The clutch trick is nice but what do you do if you have a Tip? I have an IR temp reader at work I will grab and get a temp reading off the pump and reservoir. It is a new pump so I would not expect a problem. It is significant to note that I replaced the pump because of this noise. It went away for a while but is now back. Logic would say that the reservoir is the common thread here and the most likely source of the noise.

"02996ttx50

if i had a tip? i'd just trade it for a 6mt ( kidding sorry ) but that would be my guess also. you have more of a working knowledge of the component parts, and how they work together, but, the reservoir issue is well known. at least you're fixing this stuff yourself. points for that! GL

Macster

The TSB I know nothing about but others have covered this.

In the case of my Turbo the pump was not replaced. Just the tank. The valve was bad but Porsche does not sell the valve separately so one buys the tank to get the new valve.

The tech replaces the old tank with the new tank and its new valve. Noise gone.

Be aware the power steering lines require care to disconnect/connect properly.

There's a technique that (IIRC) involves turning the connector and using a special tool to help release the quick release connector. Properly disconnecting these lines is not done using a large screw driver to pry the connectors apart.

rkellison

Thanks for the input Macster. I used a "V" shaped plastic tool to separate the red fitting. I had to push in then pull out.

Has anyone ever diagnosed and corrected the shuttle valve problem as in repaired their tank? Harmonics caused by the hydraulic flow should be correctable. It appears that everyone just replaces the tank.

If anyone has an old tank out there I would be glad to pay the postage and get it to look at before I operate on mine.

Kevin

Please note that there has been a replacement reservoir starting with the 997 part number. If you hear the high pitch whine, it is the hydraulic unloader/valve inside the reservoir/tank. Replace the tank with the updated Porsche 997TT Tippy /GT2/GT3 reservoir.

Macster

The proper tool is more 'U' shaped than 'V' shaped, that is has a 'U' shaped opening which has clearance for the connector and the legs of 'U' are then used to lever the connectors apart helped by a slight bow in the blade, but I think you used the right tool and you used the correct technique.

rkellison

Here is the latest. I got the fuel line replaced and fired her up. The noise started in a minute or two. It was a whirring sound and cane from the power steering pump below the tank. In about 15 minutes it was hot enough to start boiling the pentosin. Revving the engine would make the sound stop momentarily the it would resume. This is a new pump. I replaced the original because it was making the same noise. I know the basics about PS systems but have never seen anything like this.

Any ideas? suggestions? Cool jokes?

"02996ttx50

you have a defective pump. try another one. 996t tips are great! same pumps apparently

Macster

Certainly what 02996ttx50 offers that the pump is defective has some validity.

Obviously, a pump heating the fluid to its boiling point does not sound right at all.

What is the new pump? OE? OEM? Rebuilt? Sourced from a salvage yard?

I can't say with 100% confidence the new pump is at fault. My course of action would be to ensure there is no other explanation for the overheating of the fluid.

If not the pump then a bypass is failed or hard to believe but the hoses are not connected properly and the pump is just thrashing the small amount of fluid in the tank over and over again until it overheats the fluid.

neanicu

When you open up the system air will get inside and will make noise until it bleeds out. That might take a long time and some driving to do.
Does the Pentosin look foamy when you open the cap?
Also,if there's any way it continues to suck air into the system it will continue to make noise. But I suppose if the system wasn't sealed somehow Pentosin would leak thru there and you would see it.
Make sure everything is sealed properly and there are no leaks throughout the system all the way to the steering rack. Check lines,hoses etc.

rkellison

All valid points. The pump is OEM. Since it is giving the same symptoms as the one I took off, I would tend to think it is not the pump. My plan of action is to first look the system over for pinched lines. Confirm all is connected properly (the car is new to me and has not been driven for a while). Remove the return line from the tank and make sure I am getting good flow. Last is to drain the system looking for obstructions like chewed up O-rings and refill. If this does not uncover the root cause, I will go for another pump. More to come...