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My S550 is in the dealer for some routine maintenance and they said that they recommend that the secondary air pump is noisy and should be replaced. They quoted a price of $1,700 for a replacement. Vehicle is a 2011 S550 4matic with 171,000 miles. The price seemed high so I told them to skip for now. However I have several questions:
Is that price high? I suspect that it is.
Any idea how long the pump might last? I assume that a bearing is wearing out.
Is this a simple repair that I could do? I'm far from an expert but have done some work on cars.
What would an indy shop charge for a repair like this?
(YouTube Comment - The V6 (M272) shown in this video is pretty easy. If you have the V8 (M273), you're going to have to remove the top alloy radiator tube bolted to the thermostat(2 bolts, with one more just above the oil cooler), and disconnect the upper rubber radiator hose from the tube to get access to the right most air pump bolt. If you haven't been in there before, it's a good idea to replace both O rings (the thermostat/alloy tube and alloy tube/radiator hose connections, and make sure you spray the rings with silicone before reinstallation so they slide into place and fit back together easily) so they don't leak after all that work. You'll probably need close to a liter of mixed coolant or so to top the system back off.)
Last edited by OldManAndHisCar; Nov 3, 2025 at 10:38 AM.
My S550 is in the dealer for some routine maintenance and they said that they recommend that the secondary air pump is noisy and should be replaced. They quoted a price of $1,700 for a replacement. Vehicle is a 2011 S550 4matic with 171,000 miles. The price seemed high so I told them to skip for now. However I have several questions:
Is that price high? I suspect that it is.
Any idea how long the pump might last? I assume that a bearing is wearing out.
Is this a simple repair that I could do? I'm far from an expert but have done some work on cars.
What would an indy shop charge for a repair like this?
Thanks in advance for your advice!
This is on the easier end of DIY work. $1700 is ridiculous. Buy a Dorman pump from Rock Auto for about $125 and do it yourself.
It is fairly simple to dismantle the Secondary air pump on the bench once it is out. Mine was making a hell of a racket at 77,000mls and was told it needed replacing. I took it out, took it apart, cleaned it thoroughly, re-assembled and it’s still going at 147,000mls. From memory (unreliable as it is) the bushes inside are bronze so I don’t think i lubed anything. Probably squirted a bit of WD-40 on as is my want usually. Could save you quite a bit.
Thanks to everyone for their advice. I received an estimate from a local indy shop thats reputable for $590 vs $1,700 at the dealer. Due to a combination of my lack of mechanical skills and age - 78yo, I'm going to have the indy do it.
As the pump is being removed it is a good idea to inspect the two hoses from the pump going to the two secondary air check valves. The cause of a failing/noisy secondary pump may be from exhaust gases bypassing the check valves and getting to the pump.
The valves can be removed and cleaned very easily by your indy, and if opened up it will probably reveal that the reed is bent in to the open position. Personally I wouldn’t worry too much as they make very little difference to the o2 readings and are only used to warm the cats on start up. The pump blades prevent most of the air flow when driving.
