Hi all

I've just treated myself to a 2003 SL55 (only 26K miles) and am loving it! Still getting used to the power, but have noticed on a couple of occasions that the power drops off dramatically after I've been driving it hard for a short period of time. Have done some reading on the various MB forums (here included) and it seems that this is a bit of a regular issue, with the culprit generally being a faulty IC pump.

I've rung my local MB dealership up today and they said that the SL55 doesn't have an IC pump (!?!) and to correctly diagnose the issue, they want me to take the car in to hook it up to the diagnosis machine for a minimum of an hour at £100 an hour + tax! They couldn't even commit to diagnosing the problem within the hour!

Am going to speak with a couple of local independent MB specialists on Monday, but didn't know if anyone could offer any advice in the meantime.

The issue can generally be described as a massive drop in power after hard driving. Up to 100mph it's like a rocket, however going past this it seems to struggle to continue accelerating, although it continues to do so (eliminating a speed limiter). After slowing down to less than 20mph then flooring it again, it is very slow to pick up, as if the supercharger isn't kicking in. Drive normally/conservatively for a little while (5 mins) and it's back to normal.

I have also observed that the oil temp seems to be running at 95-100 as opposed to 80 that my old SL320 runs at, even during normal driving. Not sure if this is normal or high - any advice welcomed. To be on the safe side, I'm planning to do an oil & filter change next week as I'm not sure how long the car was stood still before I bought it (I bought it from a finance company - think it was a repossession).

Otherwise, the car's awesome!

Thanks in advance.

On the MBUSA service DVD the official term is "charge air cooling circulation pump." Your car most definitely has one so maybe it's the phrase "intercooler pump" that's confusing the dealer.

Given the age of your car and your your description of the car's performance, it's overwhelmingly likely that the pump is failing. The relevant DTB Order No. is P-B-09.41/22 a, "Check Engine Light On, Low Engine Output." You have the second symptom, of course.

If you are paying for the repair the dealer should be able to quote you a price for removing and replacing the pump. No further diagnosis should be required. A good independent garage should be able to do the same.

If your car is under warranty the dealer may have to prove that the pump is failing but if so the dealer should absorb that cost, not you.

Good luck! Let us know how it turns out.

I'd be a bit wary of a dealership that does not understand the term IC pump and how it relates to a F/I vehicle.

IC pumps have been on these AMGs for quite some time.

Thanks for the answers guys - I'll be speaking with a couple of independent specialists on Monday to see what they say.

I'm not going to be doing any serious mileage between now and then, but do I risk further damage to the engine/supercharger if I keep driving?

Also, my question about oil temperature - is this normal running temperature? If not, could it be a by-product of the IC pump not doing it's job? Not sure if the 2 are connected?

Thanks again

There's not much risk because the ECU is reducing engine power to take care of the extra heat. If you want to be even more cautious you could avoid running WOT until the intercooler pump is fixed.

I'm not sure, either. 95 to 100 sounds a bit high. I'd have to check to be certain but my recollection is that my car runs more like 85 to 90.

What is WOT?

Also, whilst I remember, how much can I expect to pay for the repair. No extended warranty and not sure if they're worth getting in UK (they seem to try to squirm out of paying for most things!), so will be paying for it out of my own pocket.

I appreciate that labour and parts will probably be cheaper in US, but I'm trying to get a feel as to how much it may cost. Maybe easier if you can let me know how many hours of labour are typically involved as well as cost of replacement IC pump.

Thanks again

Apologies for non-obvious acronyms. WOT = Wide Open Throttle.

Do a search for IC pumps on here for more detailed info, but here are the two most popular choices.

1 - Replace your older MB pump (Made by Bosch) with a newer upgraded version that I believe they came out with in 2007.
2 - Replace said pump with a non-MB pump that works...the most popular being the Johnson CM30.

Both solutions should cost around $200.00 (US Dollars) in parts or less and roughly one hour of shop labor.

I don't remember you saying if your car is stock or not, so this solution should be all you need. However, many people also get things for cooling that help a bit more also like a lower temp thermostat (search for PTE Thermostat on here) and their engine cooling fan coming on 10 degrees cooler (search for 10* fan mod). You can also replace your stock heat exchanger (called HE on here) with a larger core to help with cooling as well.

Hope that helps.

Thanks Timeless and jmf003 - good, solid answers.

Just been on the E55 forum and it looks like there was a recall earlier this year (https://mbworld.org/forums/2901494-post8.html) - my car falls in the VIN bracket but not sure if it was a US recall only or if it is valid for UK/Europe. If so, then I should be able to get the work done by the stealership without it costing me.

Do you know whether or not the recall applies to UK/Europe?

I order a Johnson CM30 for $145 with shipping.

http://apeusa.com/?jabsco

FWIW, I took a 200 mile round trip yesterday including a few full throttle bursts and my engine temp never rose above 85 C.

The problem that the OP mentions is very typical of an IC pump.

The pumps are cheap and very easy to install yourself, if you are so inclined.

As for driving it now, as said before..... there won't be a problem. There are so many safeguards built into these cars. If it is running hot, the car won't allow the SC to kick in.

You should be back up to snuff without much fuss!

Yep, mine stays at 80 unless stopped for a long period of time and it is 90*+ outside.

All sorted now - runs like a beast again!

I took it down to a local MB specialist who are spot on. Think they're going to be looking after the car (servicing etc.) in the future as they're very switched on and it's nice to keep the MB stamp in the service book. The fact that they were also servicing another 4 AMGs on the same day gives me even more confidence.

Total cost was $450 - new MB pump & relay ($300) & 2hr labour ($150), which included diagnostic check. Not cheap but far from expensive.

Thanks again to all who provided guidance.

I know how u feel, I also just got my IC pump replaced yesterday, My MB charged me $360 for the parts and also the 2 hour of labor. When I purchased my car used I didn't really notice the problem until I started reading about the issue here then I realized I had all the symptoms . So my 55 really feels like a new car now!

Glad to hear that it all worked out for you.

Bringing this back to life, as dont want to start a new similar thread...

Think I have the same problem...went on a few 3rd gear runs from 70-100 or so during some spirited driving, a few 2nd gears blasts as well. I'm all done when all of a sudden a 335i comes up (luckily there was traffic- I would of got blown away) and I put the car in 3rd ....and...and....NOTHING! OMG I looked back down and made sure it was in 3rd and the car wouldnt go at all, pedal floored.

Serious loss of power, I kinda knew, but after about 3 miles or so cruising , hit it and then felt fine. I was able to replicate the problem again later this eve...

IC PUMP?? My car is a CPO so this should be covered correct? thanks!

Sounds like you need an IC pump! Just bring it in and tell them the symptoms and they will know what to do.

There is allot of chatter about using the Johnson pump, instead of the OEM. I have had both and the new OEM was is great, which is what the dealer should install.

150 shot, same problem here. Drove the car hard, made 2 high speed passes then jumped on the bridge to head into Manhattan and a Maxima was tailing me as we got to the second turn i floored it and nothing it felt like the car was bogged down in 4 feet of mud, as the Maxima came screaming passed me i felt my heart clawing its way to my throat as my face became flush with a rush of blood that should have been drunk with adrenaline and vowed this will never happen again. I have the CPO but im replacing the pump myself with a Johnson CM30.

Thanks for the replies, does anyone know if the pump will just fail all together making the car feel like this at all times?? I could live with it for a while as long as I know not to make continuous runs..

I wont be able to bring the car in for about a month due to work, although only drive it a few days a week, just curious?

....why are people saying oil temp????...Surely you mean water temp! Mines done 24000 miles and now has the dms "600" conversion no probs yet but i guess very soon my pump will need replacing, i assume the new pump they put in is upgraded?

The OP had two questions, one about intake air temperature and the other about oil temperature. They're unrelated.

I have the newer Bosch pump and it does seem more robust than the older ones.

If I can make a couple of additional comments...

The SL55's heat exchanger is larger than the heat exchangers on some other 55K engines and it's sandwiched between the radiator and the air conditioning heat exchanger. Because of the positioning it's not really practical to swap it out for an even larger unit. Instead, the normal upgrade path is to add a second heat exchanger in series with the stock unit. The W220 cooling circuit has that second heat exchanger. Take a look at the attachments to see the stock R230 and W220 cooling setups.

Second, although the first generation Bosch unit was pretty lame, the second generation unit seems to work much better. I was able to hot lap 11.4 second 1/4 mile runs with the stock heat exchanger and the second generation Bosch pump. I've since added a second heat exchanger along the lines of the W220 setup and was able to reach 1/4 mile trap speeds of 125 and 126 MPH. In order to produce those times and speeds my engine has to be producing around 650 bhp. The second generation Bosch pump has been able to keep up with that increase in horsepower.

FWIW....