The 1997+ R129 500SL/SL500 which has essentially the same M119 DOHC V8 uses an electric air-pump, rather than the belt-driven air-pump of the pre-1997 500SL's and W124 500E's.

The cost of the "belt-driven air pump" ($900+) vs. an "electric air-pump" ($280) including all the necessary hardware, brackets, and different length serpentine belt ($300-$400 in misc. hardware) for the M119 DOHC V8 engine seems to be a bolt-on replacement.

Moreover, it seems the "belt-driven air pump" eventually goes bad AND gets more expensive, but the "electric" version is in some way simpler and cheaper in the long run.

I would think since the belt-driven air pump had an electric clutch, I could use that signal to "turn-on" the electric air pump replacement, and have a relay controlled 12VDC power source made up.

Any caveats? Any other insights or opinions?

Anyone do this? It would also remove some parasitic pulley-loss.

The 500E's "Check Engine" comes on almost every other month due to the air-pump clutch going bad, and you just can't replace the clutch!

Thanks,
:-) neil
1988 360TE AMG
1993 500E

First off, thanks for bringing this up-mine makes noise, but doesn't throw a code, yet.

Now, what does that pump do? Is it just used for cold starts to "improve" the emissions of the car (I assume by adding air to the exhaust mixture)? And if so, are there any states that check cold-start emissions?

This is a thread to watch...wish I could offer some answers, but only questions this time!

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"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Michael- unfortunately I do need it, because of the visual, functional, and dyno checks here in California.

It's also annoying to have a code thrown randomly because of it, and I just hate the sound it makes. What's worse, since my wife predominately drives it, that "Check Engine" light just scares her. With a baby in the car, I really can't convice her to do the LED pulse count test when "CHECK ENGINE" comes on.

BTW- the 1997+ M119 electric air pump is the same part number as the electric air pump on my C36/M104 engine.

:-( neil
1988 360TE AMG
1993 500E

I would think a fused/relay circuit would be fine using the clutch ECU sig.
But you may want to check the whole electric pump system as the belt drive pump also uses the same ECU sig to operate the
SOV that controls the air control valve between the eng and pump [ a parallel circuit].
There is also a check valve involved , so you may want to see if these are incorporated into the electric pump or still have to be retained from the Belt system.

Neil: While this isn't M/B-500E specific, it is related to the AIR pump. My Impala SS was getting the CE light, AIR fault code. It is an electric version. Pump fills with water from exhaust condensation, caused by a faulty check valve. A new pump is $500. This check valve which goes bad on ALL Impalas, would have been an expensive repair for GM, so-it was determined that the AIR pump was not actually needed to reduce emmissions. GM reprograms the PCM for no AIR pump and therefore the CE light does not illuminate. They place an EPA sticker on the car that allows for the AIR pump to be disabled-even in CA. Maybe this EPA variance applies to ALL vehicles?
The car passes NY state inspection even though the AIR pump is inop.
That said, switching your car to an electric version may be more involved than adding a relay because the computer may be looking at other sensors/parameters that would also need to be modified. It might be worth checking out the situation with the EPA to see if they still require the AIR pump, because your car certainly does not.
Gary

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00 Silver/Black AMG E55
96 DCM Impala SS
94 Admiral Blue ZR-1
81 Candy Apple Corvette Cpe

Neil,

Did you or anyone else ever go with the Electric Air Pump swap out?

It's about that time for mine to be replaced and I would consider the more reliable Electric option.

Ross, I traced my air-pump issue to a cracked rubber vaccuum elbow on the back of the airpump, so while the bearings are noisy for the 15-30 seconds of usage, I'm not going to change it out until it really howls.

I'd ask Donnie if this is a good swap or not.

:-) neil

Thanks Neil,

The pump noise on startup is starting to get really annoying. Looks a rebuilt unit runs about $300 from CVJ.

Has anyone found a better solution for V8's?

I wonder if there's enough 500E owners to arrange a group buy. Mine's also making the dreaded bearing noise on startup and it's only a matter of time before it needs to be addressed. Any thoughts or opinions on a group buy? I can check my sources (Dealership for an OE).......or are we better off buying rebuilt or OEM?

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Afshin

Current:
02 C32 AMG

Previous:
92 500E
84 190E 2.3 5 Spd

Just a few questions. Is this belt driven pump capable of 80 psi? Is the electric capable of the same? Does anyone know or can you estimate the horsepower required to power the belt driven pump. I'm asking for this reason. The 300 SEL 6.3, 1969 - 1972 vintage has a belt driven air compressor powering the air-ride leveling system. If this can be replaced by a trunk / boot mounted electrical pump system, I would estimate 10 addition horsepower could be available for "more usefull" services. More importantly, you could shift weight from front to rear coming very close to 50-50 and make a space available for a secret project that could yield 200 additional horse. If this can be arranged, the mighty 6.3 will once again rule the highways. Any replies, thanks in advance.

Dan The electrica airpump would go up in smoke if you tried using it for a self leveling suspension. It only stays on for less than a minute I believe. I would not try it for this application.







Neil hi there how is the east coast. You enjoyinh your new life out there.


So you got me think on this air pump deal.

You know the airpump has a K28 which is the realy that powers up the pump. Pretty much the same on all like say 97 and up cars. You know where that pump mounts. Is where the distributor caps used to be. Since our engines have that distributors drives. I don't thin you can mount it right there. Were you think of mounting it where the driven pump is now. Totally different brackets for a SL500 97 and a E500/500E.

I worked on a 97 SL today. I checked it out. So hmm get back to me I'm curious.


Guido

__________________
500E Sold
2006 Mini Cooper S
Modified,pulley,injectors,suspension
2009 E350 Sport AMG package

Guido- I couldn't tell from the EPC if the electric pump is in the same location as the belt-driven one.

Since you had a 1997 M119 engine that uses the electric pump and noted that it needs the distributorless to clear, then clearly this mod would not work as a simple bolt-on, unless it could be made to fit the belt-driven bracket.

What do you think?

:-) neil

LET ME FIND ANOTHER SL500 1997. i'LL BRING MY DIGITAL CAMERA TO TAKE PICS. bUT iF WHERE i SAW IT LAST/IT WONT BOLT UP. THE ORIGIANL AIRPUMP USES A LONG ALLEN BOLT AND A LOWER SECURING BOLT. THE ELECTRIC ONE USES LIKE A RUBBER GROMMET THAT GOES AROUND THE PUMP AS A BUFFER THEN A OVAL KINDA OF SHAPED HOLDING DEVICE TO SECURE IT. IT BOLTS TO WHERE THE PLSTIC COVERS THAT HIDE THE CAM COVERS GO


KEEP YOU POSTED



GUIDO

__________________
500E Sold
2006 Mini Cooper S
Modified,pulley,injectors,suspension
2009 E350 Sport AMG package