[OldITGuy]

Have a 2014 SLK 250 a little over a year old now with 6700 miles. Back in mid Nov, as I posted at the time, my wife and I drove to a SE US SLK meet and had a great time. Continued the drive up into NC that day and then home the next. SLK ran sweet until 30 miles or so out side Columbia when, in heavy rain, I kicked it when passing. CEL light came on and we were in limp mode. Made it home, restarted, CEL disappeared and all seemed well. Weeks later when we finally had a free weekend, we tried to take it to see my daughter but the CEL came back on before we got to the interstate. Next week, into the dealer, who updated some firmware and gave it 4 new plugs. Now being a bit gun shy I took the long way home and hammered it. Ran sweet. Last Sat we took it on our trip to Fla to see family. Ran fine for 3 hours until, again in the rain, I kicked it and the CEL light came on. I immediately pulled over and restarted. CEL cleared and off we went... very gently. Was almost to our destination, another 5+hours,(Venice) before I was brave enough to push it a bit. Ran sweet as before. Drove the H... out of it, for the next 7 days including a smoking fast run home almost all top down. Don't you love it when traffic seems to oblige your every whim?. Great fun!

Point of all this is, the two and ONLY two times we've driven our SLK in the rain, we've had problems. Wife is NOT happy to say the least. Dearly loves our SLK but is seriously irritated that we're having these problems. Any one else have similar problems or or any suggestions as to what might be the problem? Obviously water is getting some where it shouldn't but only shows up when under heavy load.

Planning to take it to the dealer in a week or so and avoid rain until then.

 

[jbanks15]

Was the rain heavy? here is my tale from my previous 05 slk 350 in 2006:

http://www.slkworld.com/slk-r171-general-discussion/456-dark-stormy-night.html

 

[OldITGuy]

First time was heavy rain. Second time was very light, on and off, just enough, mostly, to kick the ww on. Second time, standing water was minimal although I'm sure there was some. Both times running 70+ with engine up to temp.

 

[wja96]

Well, if the dealer gives you any hassle, just tell him that these cars are used extensively in the UK where we had to invent the watch because sun-dials don't work

It rains here all the time (pretty much literally all the time) and SLKs run just fine.

I suspect you're missing a bit of trim or something that should deflect the rain water away from an air intake. Or you have the correct deflector fitted but it's upside down or a bad sensor or something silly like that.

I'm sure you'll get it fixed quickly.

 

[OldITGuy]

Happened again. Same as last year, 3+ hours out on the way to Fla in the rain. Now have an answer directly from MB.

Apparently there's a design flaw with the air to air inter-cooler. Applies to 2014 SLK 250s and probably all R172 250s up to 2015. Does NOT apply to 2016 forward. Also applies to some C300s. The problem shows up after long (2.5-3.5 hours based on our experience) in very high humidity (rain/mist/heavy fog...) at relatively high speed (60+ again based on our experience).

Apparently, the design of the inter-cooler allows water to build up somewhere in there to a point that when you goose it a bit, the water is ingested causing the computer to think there's a problem and into 'limp mode' you go. At this time there's a fix for the C300s involved (I 'think' something about drilling a very small hole in the bottom of the inter-cooler) but none for the 250s due to the fact that the inter-cooler is at the bottom of the radiator (Again, if my understanding is correct).

So.... Fair warning.

Note that this is a very specific set of circumstances and that resetting the system clears everything up. Note also that the last two times we've had this happen, we've reset the system and driven another hour or so in the rain without any problems. We're hoping to hear back from MB in the next 30-45 days as to a fix. More as we know it.

 

[jbanks15]

At least you know. where in Floriduh you at?

 

[OldITGuy]

After going around with the dealer & Mercedes, it appears that there isn't a fix and there will NOT be a fix. There is a bulletin acknowledging the problem but it seems Mercedes doesn't feel that it's a safety problem and that since it only affects SLK 250s in the south eastern US it's not worth the effort. Needless to say we're not happy about this. Dealer even low balled us on trade in value saying they'd have a problem selling it. Looking into an alternate solution....

Also, it appears that Ford's Eco Boost (turbo system) may also have the same/similar problem. Many complaints on the net.

 

[wja96]

After going around with the dealer & Mercedes, it appears that there isn't a fix and there will NOT be a fix. There is a bulletin acknowledging the problem but it seems Mercedes doesn't feel that it's a safety problem and that since it only affects SLK 250s in the south eastern US it's not worth the effort. Needless to say we're not happy about this. Dealer even low balled us on trade in value saying they'd have a problem selling it. Looking into an alternate solution....

Also, it appears that Ford's Eco Boost (turbo system) may also have the same/similar problem. Many complaints on the net.

Brabus kit. Bigger intercooler, slightly different location.

 

[OldITGuy]

Checked them out but didn't see anything about a new/different inter-cooler set up. Do you happen to have a link?