What does this pipe do ??? 300CE 24v - PeachParts Mercedes-Benz Forum

Larry Smith · #1 05-03-2002, 07:22 AM

I'm confused
I posted a query a couple of days ago about my power steering hose pressurising and depressurising at 4 second intervals when the engine is running..

Having taken a second, much closer, look the pipe in question it is not a power steering pipe.

However, it does appear to connect to the power steering pump under some kind of shield plate under the fluid reservoir on the side furthest from the engine.
It is solid at this point approx 1/4" dia but as soon as it leaves the pump it becomes a black rubber hose and goes across the front of the engine above the top pulley and then goes back to the bulkhead adjacent to the steering box and then becomes solid again. At this point it then joins two other pipes, one the same size 1/4" and one slightly larger 3/8" coming from the ASD system oil tank the three pipes disappear together down beside the steering box and then go down under the car towards the back of the vehicle.

I still have the fault where this pipe in question is pressurising and the rubber section goes rigid and then it relieves somewhere and relaxes and then repressurises over a 4 second cycle. You can hear this as a thumping noise sat in the car with the engine running. This is how I found it in the first place.

I've looked at pictures in the Haynes manual for the 24 valve engine but this pipe does not exist on their vehicle.

Help in identifying this pipe and fixing the reason why it keeps pressurising and relieving would be much appreciated
Larry

Gilly · #2 05-04-2002, 12:17 AM

Yeah, I saw that post, I had no idea what you meant. Now I do!
That's the heater hose! The reason it pulses like that is due to the heater valve opening and closing (pulsing).
Gilly

Larry Smith · #3 05-05-2002, 03:10 AM

I'm confused here, if this pipe is a heater line then why does it run underneath the car to the rear of the vehicle alongside the ASD pipes. Also why is the solid section 1/4 inch pipe .
This seems to me to be a pressure line of some sort but for what system ,I do not know.
I suppose my for my next step I will have to put the rear wheels on ramps and depanel the underside to see where it connects at the other end.
Larry

Gilly · #4 05-05-2002, 01:36 PM

Larry:
Do the hose ends connect to the metal pipes with plain hose clamps, or does the metal ends have those crimped connectors?
Gilly

Larry Smith · #5 05-05-2002, 08:21 PM

One thing I forgot to mention in this popsting that was in the previous is that the car is a RH drive UK model therefore the steering box is on the RH side of the car and thats where the pipe in question is.
Larry

Larry Smith · #6 05-05-2002, 08:25 PM

Its crimped

Gilly · #7 05-06-2002, 12:25 AM

Larry:
I'm completely stumped. If you will humor me, check this out one more time, but make sure the climate control is shut off (O button is pushed). It sounds so much like what the heater hose does when the heater valve is pulsing that I'm wondering (no offense) if you are somehow following the routing incorrectly?
Gilly

Larry Smith · #8 05-06-2002, 04:51 AM

The routing is from the pump on the LH side of the engine (above A/C compressor) It connects to the LH side of the pump underneath the fluid reservoir. Just clear of the pump it changes from 1/4 dia to rubber and then goes across the front of the engine very close to the top pulleys and then goes to the rear bulkhead changes back to solid and then goes down underneath the car along side the ASD lines to the back of the vehicle behind the under body panels.

Please see the attached pictures.

Larry Smith · #9 05-07-2002, 05:51 AM

Does no one have any ideas ?
Please see the pictures I have added
Larry

400E · #10 05-07-2002, 08:47 AM

Larry,
Glad to see I'm not the only one scratching my head over this one!

After doing some detective work in the repair CD, I bet you've got automatic level control. If so, you have a "tandem pump" in which the power steering pump and the level control "oil pressure pump" are driven by a common shaft. Do you have a separate oil reservoir under the hood? If so, you've got level control. That would explain why a pressure line would originate from around the PS pump and head towards the rear of the vehicle.

I don't know what to make of your symptoms, but I did see in the CD-ROM a nice algorithm for checking out the system. It's in section 32-0501 in the Chassis and Body CD.

Larry Smith · #11 05-07-2002, 11:01 AM

Thanks for the reply but I dont think I have the auto level control. I dont think that was fitted to the Coupes and it is not in my handbook.
Is it something to do with the ASD system? That is fitted to this car, however I think that uses an electric pump.
Maybe the next step is to depanel the back end underbody and take pictures of where the other end of the pipe connects
Thanks for your efforts
Larry

rbn3 · #12 05-07-2002, 11:01 AM

Coolant is routed to the windshield wiper to melt snow and ice from the base of the arm. Could this be the pipe you are pointing to?

Larry Smith · #13 05-07-2002, 11:07 AM

I do have a seperate oil reservoir on this car but I'm pretty sure it for the ASD system

Larry

ke6dcj · #14 05-07-2002, 12:24 PM

I agree, the connector & hose looks like the self-levelling hoses in our wagon and 500E.

HOWEVER, it could also be ASD. Check your rear suspension.

If you have struts that have a hose/pipe going to them, then you have self-levelling.

If you have hose/pipe going to the differential, I believe that's ASD.

:-) neil
1988 360TE AMG
1993 500E

Larry Smith · #15 05-07-2002, 01:08 PM

I definately have ASD on this vehicle but my understanding was that this was pressurised by an electric pump to lock the differential.
Does the ASD system use perssure from the steering pump ???.
Are there two pumps in one here because the fluid is different for both systems

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