SLK.........Diesel vs Petrol, some advise please.

[Reggie-rock]

Hi all, I am still considering buying a 2012-2015 SLK but should I have petrol or diesel ? the majority of my journeys are around 12 miles or under on country roads where the speed limit is 60 mph. I go down to london every 6 weeks or so which is over 100 miles on motorways but is that enough to consider a diesel ?
So far I have been considering petrol engine SLK but as the diesel is only a 2.1 litre, should I consider it as it is a small engine to warm up on the shorter trips I do.

 

[Tiim533]

From all the stuff I've read, Petrol for you!

 

[Chrishazle]

Diesels take noticably longer to warm up than petrol. With my C220 I'm about 4 miles away before the engine is up to temperature and the heater working well, whereas with the 968 cab it's quite a bit less than a mile. I'd go for petrol.

I've also been thinking about swopping the 968 for an SLK, but for my money it would have to be a petrol 320/350 (management won't allow me a 55AMG ) which I guess is the model before the one you're thinking about.

 

[steve333]

Hi my wife has had all 3 of the slk shapes,a 230k petrol,200k petrol and a 250 cdi(2014/64).We test drove a petrol 200(2014) but chose the diesel as it was a better allround drive and better fuel consumption(always averaged 48mpg over a tank)-the petrol version was actually noisy like a diesel(fuel pump),drive both and see which you prefer.

 

[markjay]

You should also consider the dreaded DPF issue on low-mileage Diesel cars.... and the cost of other potential repairs, which on a modern Diesel engine can be very high (ask how much a high-pressure Diesel fuel pump cost....).

So if you are not planning on 15k+ annual mileage, Diesel will have no real advantage for you.

As for fuel consumption, if your overall annual mileage is low, then the saving from using the more-frugal Diesel engine will be very low in absolute figures anyway (especially if you factor-in the highest cost per litre of Diesel oil).

And last... with Diesel becoming the 'fuel of Satan', it is likely to escalate in tax and possibly also suffer lower residuals in future.

Said that... if you are planning on towing (well probably not with an SLK...), or you just like the low-rev torque of the Diesel engine, than that's a factor in favour of Diesel.

 

[GeeJayW]

Firstly, there is no approved towbar for an SLK, so if you did have that in mind forget it.

A neighbour had the SLK250 CDI and liked it, but not enough to get another at the end of his deal. He's gone with a VW saloon/coupe thingy the name of which escapes me at the moment.

We had the R171 SLK200, but that had a 6-speed manual box. Enjoyed that for the seven years it was in our possession and it averaged mid 30's mpg over the time we had it, but would do 40+ on a longer journey. Drove the R172 SLK250 petrol with 7-speed auto when it was launched. I thought the auto box let the car down from a driving perspective.

However since 2015, we have had a C-class coupe and now our current car, both diesel and 7-speed auto and have enjoyed driving both.

If I were looking for an SLK again, I'd retry the auto petrol version especially if mostly doing shorter journeys. The fuel economy/sports car discussion doesn't work for me. The only reason for me to for the diesel version would be for the low down torque. Diesel and short journeys is not a good combination.

 

[Deleted member 6183]

The Mrs has had 2 petrol SLKs.

The first was a R170 320 which we both enjoyed, surprisingly good on fuel on a run, plenty of go and very reliable.

Her current is a R172 250 with the utterly pointless AMG style body and suspension. At first I liked it a lot, nippy and comfortable enough. WShen sourcing it I found that all the 250s that I spotted had good spec and the AMG bits.
As time has gone on I'm a little less impressed, the ride is too hard, the engine too noisy, it leaks, it's bloody black and cannot be kept clean.
On the plus side it has that cute analogue clock on top of the dash and the magic sky tinted glass roof.

 

[E53AMG]

Sports cars and diesel to me are a contradiction. Diesels are good in boats, tractors, lorries and long distance saloons but if you pull up in your sports car, roof off but engine rattling away it sort of detracts. Can you imagine a Ferrari, Lambo or Masser chugging away at the traffic lights?

Ok the above is a bit tongue in cheek and my Jag XF 3.0l diesel went like a bat out of hell but it was still rattly on tick over and not refined enough for a sports car.

Sent from my SM-G955F using Tapatalk

 

[PobodY]

^Especially with the top down. - It makes me slightly sad to hear/smell a sleek car like a SLK with a diesel lump in it.

There's more to life than fuel economy.

 

[Eddy77]

Petrol for me. But I think that with a regular 100 mile motorway trip, you shouldn’t suffer DPF blockage issues. Our family car is a diesel. Spends most of its time short trips around town. But every two weeks it does a 70 mile motorway trip. Never had a dpf light in 8 years of ownership. 100 miles every 6 weeks might be pushing your luck if lots of short journies in between but you may be ok...

That said, personal preference is petrol for a cabriolet!

 

[Piff]

Contrary to the above, we had a 250 diesel SLK and it was a great car. Easy to drive, loads of torque and around 200bhp. Good fuel economy and no dpf issues despite the majority of journeys around 4 to 5 miles.
Wanted a runaround for SWMBO and went for a 2008 facelift 280 with all the toys & very low mileage. It’s a lovely car but quite “heavy” to drive. No doubt good on a track, but for day to day road use no better than the diesel. V6 has a nice sound though, particularly with the roof down.

 

[Reggie-rock]

Thanks all for the great advise and have decided it will be a petrol SLK.

 

[gIzzE]

I bought my self a C220cdi as a cheap run around recently, sorry, but I just don't get 4cyl diesels apart from to save money. They really don't suit what is meant to be a refined German car.

I have mentioned this before, neighbour had the 250cdi and swapped for the 250 petrol, he went from 42mpg average to 37mph average calculated.
Doing 20k miles a year he says it is costing around £4-5 a week more to be in the petrol, he is thrilled to bits.

I think he was expecting it to be like his last petrol which was 6cyl BMW 528i, which was 25 years ago, he has only had diesels since and didn't consider that petrols have probably moved on far more than diesels economy wise.

The gap is so close now it makes very little sense, especially for those buying new.
Normally works out around 3% of overall costs going diesel vs petrol once you consider depreciation, insurance, tyres and fuel on a new car.

Plus with new petrols being turbo anyway, the old forced induced vs na argument is not more either, the petrols drive like a diesel anyway, the main difference is nice sound, more refined and more revs to play with when having fun.

 

[Alex225]

Thanks all for the great advise and have decided it will be a petrol SLK.

Good choice. I would have backed the petrol camp as well.

There is of course the whole point about diesels in a sports car as it does seem contradictory but at the same time the appeal of high mpg if you're doing long drives I get.

Sounds like you're driving is all short journeys so you likely won't benefit as well from diesel. Although not an SLK my old E Class takes ages to warm up and then when on a run returns 45/46mpg. By contrast on the rare occasions I take it the train station for work which is 4-5 miles away, it's indicating 23mpg. As mentioned you also have the DPF issues which don't take kindly to short runs so could completely offset the saving in fuel.

Good luck OP, hope you enjoy your SLK when you've found one.

 

[grimree]

The OP's made his decision so nothing more to say - except perhaps on the diesel/sports car issue - seen the performance figures?

 

[gIzzE]

Although not an SLK my old E Class takes ages to warm up and then when on a run returns 45/46mpg. By contrast on the rare occasions I take it the train station for work which is 4-5 miles away, it's indicating 23mpg.

My E350 S212 3.5 litre petrol used to do better on the 6 mile school run than the E350cdi I had, and on a run would be about 35-38mpg, the E350cdi used to be about 38-42, the main difference was the OBC used to lie more on the diesel.

But that was sort of my point about diesel vs petrol, too many of us buy big petrols to have fun in and small diesel to bumble around in and so drive them differently and then look at the mpg averages and they are miles apart.

I have had so many of the same car in the petrol and diesel version now and to do the same job, slogging up and down the M11, and I can say that the difference between a petrol and the equivalent diesel is somewhere between 10-15%.

That is 3.2fsi vs 3.0tdi, 530i vs 530d, 335d vs 335i, E320 vs E320cdi, E350 vs E350d, 2.0tdi vs 2.4tfsi etc. etc.
I am not talking about a 1999 W210 E320 petrol vs a 2018 C220d, but like for like.

I really wish manufactures were taught to understand this more too, and pass on the info to customers, we would have so many more petrols sold.
Also the new MPG figures may help sell more petrols. The US system for measuring mpg is far better, when you see it says E350d is only 10% better than the E350 petrol in official figures, and figures that are right not hot air, you can see why they sell so few diesels.

Then you have the price points, I see the Mercedes finance figures are showing the E200 petrol is coming in at just over £70 a month less than the E220d on the 10k miles per annum package, for someone doing that mileage. That covers over half your fuel bill, it makes the petrol substantially cheaper to run.

I genuinely see no financial reason for people to buy diesel now.

 

[gIzzE]

The OP's made his decision so nothing more to say - except perhaps on the diesel/sports car issue - seen the performance figures?

SLK 250 cdi 204hp, 0-60 in 6.7 seconds
SLK 250 204hp, 0-60 in 6.5 seconds.

The 0.2 seconds is probably down to kerb weight or gearing.

So similar not worth worrying about, what was your point?

 

[grober]

If you are talking about the R172 second hand your problem may be locating a 4 cylinder petrol as Mercedes pushed/ stocked the diesel version in preference at that time. I suspect because all OM651 diesel engined cars were more profitable engined models [sheer production economies of scale] than their petrol equivalents. The diesel engined SLK/SLC were never sold in the US and Canada.
Mercedes-Benz SLK-Class (R172) - Wikipedia

 

[Mr Filipov]

Sports cars and diesel to me are a contradiction. Diesels are good in boats, tractors, lorries and long distance saloons but if you pull up in your sports car, roof off but engine rattling away it sort of detracts. Can you imagine a Ferrari, Lambo or Masser chugging away at the traffic lights?

Ok the above is a bit tongue in cheek and my Jag XF 3.0l diesel went like a bat out of hell but it was still rattly on tick over and not refined enough for a sports car.

Sent from my SM-G955F using Tapatalk

All I will say to that is Ghibli and Levante

 

[Yugguy]

VW are trying to rescue diesel, pointing out that the latest ones are cleaner than ever. Wether that's true or not I can't say but contrast that with other manufacturers who are ditching it in favour of tiny turboed petrol or petrol hybrids.