redaotrosh

Hello Guys, I have S320 99 (Germany Model), I have replaced the air compressor 3 times in 3 years, the fuse and the relay is ok, when I diagnose it by SDS I have found that there is a leak in the line between air compressor and the valve, I have made soap test for all the lines, compressor and valve nothing shown.
My questions: In normal condition without any leaks, after startup the car, compressor must engage for 15 sec, so if I am in stop and go or hills and bumpy road will the compressor engage again or not(every couple of minutes). In highway does the compressor will engage as the same behavior each round of time. Cause I am thinking to replace the valve block but I want to know the behavior in normal condition in order to distinguish the issues early before harming the compressor again. is that normal to replace 3 compressors in 2 to 3 years and how much the mileage of the compressor in unleaky system.

Note: After checking the defective compressor by SDS it give maximum 6 bar, and air pressure valve below 2 BAR (greeen area) while the new one is >14 BAR and the air valve pressure is around 3 Bar, any advice. while replacing the piston ring and the head didnt fix the issue.

Sorry for my English an thanks for patience.

wallyp

"is that normal to replace 3 compressors in 2 to 3 years and how much the mileage of the compressor in unleaky system."

No, it is not normal to replace the compressor that often, and in a non-leaking system, the compressor should last for many years.

My first suspicion is that you have a leaking valve in the Airmatic valve body that is over-stressing the compressors by dumping air constantly at a slow rate. There will be no visible leak, just a small, but constant flow of air from the inlet/outlet hose.

redaotrosh

Yes I guess that too and SDS penumatic test show me that line between pump and valve is leaking but did I need to replace the line or the valve or both

bamberger_1

The times the compressor engages is very much depending various circumstances. The regular pattern does not prevale. Temperature, pressure, road conditions, speed, car weight, .......
I believe you did replace the compressor by a cheap Chinese product. I once did this and it lastet 1y only, pressure dropped from 15 bar to <6 bar after 12 months. The one and only compressor is WABCO, nothing else.
when the diagnosis says the connection between compressor and valveblock is defective, replace it. But it can as well be the worn compressor, piston, piston ring, or the thread of the compressor nipple the defective.

tusabes

If you are using cheap parts it is completely normal to replace that often

Wabco or Arnott with lifetime warranty

redaotrosh

I always replace with Wabco pump since i cant get new parts in lebanon and the last one get it from 2009 car parts

wallyp

Some careful bubble testing should show you whether or not the line or its connections are leaking. If it isn't leaking, the valve block is the next logical suspect. Some valve blocks are rebuildable, some aren't. If yours is rebuildable, that consists of a teardown and inspection, and replacing O-rings.

tusabes

so you are replacing with used parts ? You can’t expect used parts to last long

redaotrosh

We cant find new parts here in lebanon or we can get chinese new part so it is better to get used one(germany parts).the compressor pressure is 15~16 under testing.
tomorrow we will make tests for the line between pump and valve block and I will get another valve(used) for testing.

My town located at hill, and the roads is up and down, sometimes bumpy and most of my trips not more than 1 to 2 mile with stop and go, does the pump engaged more in that situation or it is independent of that. (I notice every startup the car the compressor engaged for 15 second, even if I stopped the car at super market for 5 minute and in inclined road I noticed the pump engaged more).

wallyp

The fifteen-second operation at start-up is normal. The car will usually release air when it rises as weight is removed - that is, when you get out of the car. When you restart the car, it has to replace the vented air.

Continuous operation as you drive the car is not normal, and will lead to an early death for the compressor.

You can sometimes improve the operation of a worn compressor by replacing the single piston ring in the compressor. Replacement rings are usually available on-line at a reasonable cost - a repair kit (piston ring, gasket, replacement bolts, etc.) is about $25 US for us here.

redaotrosh

Hello guys,

kindly find the below analysis by SDS that I did last Saturday.

1. I did soap tests for all the lines plugs at Valve block and the line between between Pump and the block (Negative).
2. Line between block and reservoir there is junction and sometimes it is leaky but by SDS it is under recommendation.
Pneumatic tests done as below
1. Pump test, pressure above 14 after 5 seconds and relieve pressure 2.9 bar and relive valve test the pressured constant at ~2.9Bar.
2.Valve block and reservoir test, Pump enaged for several seconds and the pressure reduced less that 0.3 bar during 120 Sec( MB recommendation <0.5 in 120 Sec).
3.Vale block and Pump, pump engaged for 3 sec but the pressure reduced 2.5 Bar during 120 Second so positive test and there is a leak.
4. Valve block and Struts the leak is below 20 MM in 10 hours.

I checked for several stores in Lebanon but I didn't find any used or new valve block and the air lines to replace the air line between the block and reservoir, so I make a repair for the line and the leaked reduced from < 0.3 bar to <0.15 bar. I can't make a rebuild for the block since I don't have the tools, due to economic crisis in my country we can't transfer money outside and I can't buy from online stores since the Banks decline any international transaction without approve from the bank directly. So what should I do until I can get a valve block and is that leaks will affect the pump directly or not.

Thanks.

bamberger_1

The compressor is built for intermittent operation. So the more often it runs, the larger the wear. As soon as you can get the proper parts you need to consider to replace the compressor as well. BTW the pressure lines are regular 4mm nylon hoses, you can get in any place selling compressors or similar tools. Normally the lines itself are not leaking, most of the times the nipples on the valve block and/or the reservoir are leaky. In order to fix that, try soap water and detach the faulty line, cut the hose 5-8mm, clean the seat, check the O-ring and reconnect the line. Watch out fastening torque is ONLY 5Nm. The hose should go into the nipple about 12-15mm.

wallyp

How dusty are your driving conditions?

Is the inlet air filter in-place and in good condition? It is just a small in-line fuel filter. Are the lines and fittings between the filter and the compressor in good condition?

Based upon my (pretty poor) understanding of your situation, I would be driving the car and enjoying it, and trying to prepare for the next failure.

redaotrosh

Thanks guy I will try my best to find the parts in another stores. hope the pump will not wear until valve replacement.
My driving is 5 KM morning and 5 KM evening during weekdays and at weekend I move around 5 to 40KM(stop and go mostly and each continuous trip up to 5KM) and one to two times per month around 140KM(highway).

Regards,

redaotrosh

Hello guys,

Due to coronoa situation I can't find the valve block. But I am facing an issue now that every couple of seconds the pump engaged for 3 second and ***** sound can be heard so what does the issue is it from the relay or valve block please advice since all garages closed in Lebanon and I am trying not to use the car for more than 300 meter in trip.

wallyp

Where is the "pssst" coming from?

\The only person who can have a chance of finding the problem is you.

redaotrosh

I heard the sound clearly from my side (driver side) maybe from resevoir or like that.

redaotrosh

I have checked it today at STAR.all tests done and checked, no leaks and no issue in airmatic, only the same leak issue between valve and compressor with the same value, I had replaced the relay with hella one and I did recalibration for the car. But the issue still the same in any inclined plane up and down the compressor engage and release then engage then air release, enagaged for 5 second then release then after couple of second engaged no idea why please help what should the issue is it ECU or valve block need to be replaced
78

I have a trip next tuesday about 150 km and afraid to worn the compressor

redaotrosh

Guys i checked the car again in my carage, i saw thay the filter hose cracked so I replaced it with new one and filter so I didn't hear hisssss sound again every couple of seconds but now I don't know if the compressor running too much again in my heavy inclined road so any advice