Air pump noise after start up?

[dds28]

Hi everyone,

I recently noticed on my 95 e420 the air pump bearing was getting noisier. A few days ago, when the engine is cold, I hear what seems like an exhaust leak, kind of like a hole in the exhaust type of noise from the right side of the engine. After about 2 minutes from a cold start, it goes away. Is this the start of a failing air pump? Should I start looking for a replacement?

 

[gsxr]

More likely it's a broken hose at the air pump outlet, but it could be the air pump itself. Check it out with a flashlight at the next cold start.

 

[dds28]

I'll check that. Thank you sir! If I need a replacement, where do you recommend to buy a remanufactured one?

 

[gsxr]

If it only needs hoses, replace those first.

If the pump itself is noisy due to failing internals, look for a rebuilt / remanufactured one (not cheap).

 

[dds28]

Here is a short video of the noise shortly after start up and after 2 min of idling after clutch disengages, I didn't find any holes in the hose but could have missed it by looking in the wrong places.

 

[gsxr]

Might be the pump itself...

 

[dds28]

Thaks Dave. Does $400 sound about right for a remanufactured one? Would you recommend C&M Hydraulics?

 

[gsxr]

Thaks Dave. Does $400 sound about right for a remanufactured one? Would you recommend C&M Hydraulics?

Yes and yes. I'm not sure who else rebuilds these.

 

[emerydc8]

I installed a C&M pump about 15 months ago and have had zero problems with it. I bought it from FCP Euro. They’ve gone up significantly since then.

https://www.fcpeuro.com/products/mercedes-air-pump-119140178588a

 

[Berglund]

Regarding this air pump
Isn’t it possible to ”bypass” this air pump by replacing the multi-belt with a shorter version?

 

[gsxr]

Regarding this air pump
Isn’t it possible to ”bypass” this air pump by replacing the multi-belt with a shorter version?

If the bearing is good in the pump you can simply disconnect it (unplug the electrical connector).

Completely removing the pump requires replacing it with a bracket and idler pulley, which are NLA from the dealer.

 

[Berglund]

If I want to remowing the pump..
Will it be possible to find a complete kit with bracket and pulley to find after market!
Some one seen or built anything?

 

[lowman]

There is also an airpump delete kit available made by a german company. New bracket/pulley bracket and pulley

 

[gsxr]

There is also an airpump delete kit available made by a german company. New bracket/pulley bracket and pulley

Cool! Have a link?

 

[lowman]

Here is a link for the company. Lots of goodies here. They also do repro rear transmission mounts, NSS for the v8"s, etc etc.

Kurth Classics Autoparts

hier findet Ihr Mercedes Ersatzteile in Original oder verbesserter Qualität

kurth-classics-autoparts.de

 

[lowman]

Cool! Have a link?

yup.Posted a link below..but here is also a link directly to the "500e section" Lots of goodies on there

Startseite

kurth-classics-autoparts.de

 

[Surf Blau]

Agreed, Kurths is great - here's a link directly to the kit as well: Mercedes M119 Ersatzkit Sekundärluftpumpe (Var: 6-Rippen Riemen)

 

[lowman]

And here is for the 8 rib belt version

Mercedes M119 Ersatzkit Sekundärluftpumpe

Bei uns bekommen Sie alles, was Sie für eine erfolgreiche Reparatur Ihres Mercedes Klassikers benötigen

kurth-classics-autoparts.de

 

[JC220]

I plan on making a small production run of m119 air pump delete brackets next spring. They will be well made and considerably better priced than the ones linked above.

 

[JC220]

Waterpump delete?wow..thats interesting

Oops sorry- corrected now

I am typing from a boat in Italy

 

[gsxr]

Agreed, Kurths is great - here's a link directly to the kit as well: Mercedes M119 Ersatzkit Sekundärluftpumpe (Var: 6-Rippen Riemen)

Thanks! Interesting design, it only replaces the air pump, and uses the existing bracket. THis is different than the factory solution but may use the standard belt length (I think the factory setup uses a different belt length). €280 w/VAT, maybe ~€240 without VAT. Probably €300+ with shipping/tariffs to USA, $350-$400 USD total delivered? Suddenly a reman air pump doesn't look that expensive.

 

[gsxr]

I plan on making a small production run of m119 air pump delete brackets next spring. They will be well made and considerably better priced than the ones linked above.

Oooo - looking forward to more details on this, Joe!

 

[dds28]

I think my pump is definitely giving up.I can still drive the car and the clutch still disengages. I started smelling what seems like burnt plastic/rubber on start up the other day while I had the hood up. I see some rubber on the grooves. I take it if I do t want to get stranded, I should t drive the car. Other than the rebuilt pump, the hoses, and a check valve, is there anything else that’s needed for the job? What are the part numbers for the check valve and related hoses? Thanks!

 

[gsxr]

If the pump pulley bearing is OK and it's quiet when disengaged, you can drive the car with the electrical plug disconnected. This will trigger the CEL after a couple of cold starts, but it lets you drive the car until you are ready to replace the pump.

The pump R&R isn't complicated, but the factory connection for the electrical plug is buried up against the fender, almost impossible to access without removing the washer reservoir (IIRC). It's Zip-tied in place, you'll have to remove the factory zip-tie. If the plug is easy to access, a previous owner had already messed with it (nobody puts the electrical connector back in the factory location).

Search the forum for hose part numbers. The check valve can probably be re-used, but make sure the pump doesn't require a new one for warranty purposes.

Only thing I can think of to watch out for, if you remove the bracket from the engine, you MUST clean the threads and apply fresh anaerobic sealant to the bolts before installing. Otherwise you'll get a sizeable oil leak afterwards. See photo below.

 

[emerydc8]

Have you tried just unplugging the pump in the mean time to see if it still makes noise? If it’s just making noise on startup when the pump is engaged and goes away when it warms up then the temporary (or permanent) solution is to simply unplug it.

 

[dds28]

I haven't tried unplugging it but I will. Bearing noise noticable but not crazy loud. Does the oil filter housing need to come out to access bolts for removable?

 

[gsxr]

Oil filter housing remains in place, untouched.

You'll have better / easier access to the alternator with the air pump out, so if you need to mess with the alternator for any reason, combine the two jobs.

I forget if the air pump job can be done with the fan clutch + shroud in place. It is likely much easier with those items removed. Haven't done this in years, my memory is foggy.

 

[dds28]

Is this the plug?

 

[emerydc8]

No. The oil filter housing doesn’t require removal to replace the air pump.

I was able to replace my pump last year without removing the shroud. To find the plug just follow the wires from the pump to the passenger fender-well area where the windshield washer reservoir is mounted. Like Dave said you’ll probably have to remove the reservoir to get to the plug if no one has tampered or replaced it already.

 

[dds28]

That's good. Thank you

 

[gsxr]

Is this the plug?

Nope, that is not it. You'll need to trace the air pump wire and find the other end.

What's visible in your photo is the electrical connection to a vacuum solenoid/switch for the EGR valve and/or air pump valve, located nearby where the air pump wire connects.

 

[dds28]

Thanks Dave. I will go look for it again

 

[dds28]

Is this it？

 

[gsxr]

Is this it？

I believe that is probably it. Looks like someone has had the air pump disconnected in the past, or you wouldn't have found it that easily.

 

[dds28]

I agree. Definitely someone routes the wire incorrectly. I just unplugged it and started the engine. Air pump clutch definitely didn’t engage. No CEL I was expecting it to light up.

 

[gsxr]

I agree. Definitely someone routes the wire incorrectly. I just unplugged it and started the engine. Air pump clutch definitely didn’t engage. No CEL I was expecting it to light up.

It make take a couple of cold starts before the CEL turns on. A fault code will be stored immediately on the LH module, but the DM waits to see the fault a couple of times before triggering the CEL. This won't hurt anything, ignore the CEL...