Newbie. SL advice needed.

[Pcn1]

Hi,

Been thinking of a 90's SL for some time now. Have viewed a couple with some help from posters over on PH. Would like some more advice on buying a SL from this era, is there any website's I should check out?
Have been told the 320 is the best of the engines (280 a bit underpowered and the 300-24 is a little revvy) Also at this age they all need head gaskets doing if not done already!
One other question is are the early 90's SL's different from the late 90's SL's?. I find the early one's can ask more money for a similar spec car so was not sure if they are more desirable for any reason.

Thanks

 

[BTB 500]

Hi and welcome.

Do some searches here - this is quite a common request. The model you are interested in is the R129.

IMO the 'best' engine is the 5 litre V8. It's a 2 tonne car, and there's a lot to be said for having a big unstressed engine. Even if you do significant mileage, the difference in fuel consumption is not that great compared to the smaller engines. Properly maintained, the V8 is extremely reliable.

The R129 SL had a major facelift around 1996. Facelifted cars are generally more desirable (better interior, 5-speed gearbox as standard, etc.). There was another facelift around 1999.

 

[IanA2]

What Bills says.. except I think the early 90's models were better built.

 

[Pcn1]

Thanks for the feedback so far. I kinow you guy's hear the same questions time again so apoligies to all.
This would only be a weekend car for me and I dont feel any desire to try and get any facelift models. I run a 1992 Porsche 944 S2 as well and like the thought of driving around in a cars you dont see on every street corner!
Would you turn down a SL280 if the price was right or are they just best avoided?

 

[BTB 500]

Would you turn down a SL280 if the price was right or are they just best avoided?

I wouldn't want one. 10 secs 0-60 and still only 23 mpg (combined).

 

[IanA2]

I wouldn't want one. 10 secs 0-60 and still only 23 mpg (combined).

I'm sure I get more than that from the 500....

 

[BTB 500]

I have had a whisker under 30 mpg from my 500 (over a tankful, with a lot of motorway cruising). It's cheaper on fuel than the Vito - MPG is about the same, but diesel costs more.

 

[IanA2]

I have had a whisker under 30 mpg from my 500 (over a tankful, with a lot of motorway cruising). It's cheaper on fuel than the Vito - MPG is about the same, but diesel costs more.

Sounds about right to me, I always guesstimate it to be between 25 & 30. The M Class delivers 19.8 ! (it's got a computer thingy), havn't got a clue what the 60 does....probably between 20 and 25.

 

[Stratman]

Forgive me for going off at a tangent but this discussion has in it a perfect example of something that has been bugging me for years.

Two SLs driving along the motorway side by side doing the same speed. One, a 500 is doing about 28mpg and the other, let's say a 300 is doing about 35mpg. Same speed, same car, same air resistance so they are producing the same power, but one is burning 25% more fuel to achieve it. What's happening?

 

[IanA2]

In fact I think the 300 would be using more petrol. Smaller horse pulling bigger cart needs more oats!!

 

[BTB 500]

Two SLs driving along the motorway side by side doing the same speed. One, a 500 is doing about 28mpg and the other, let's say a 300 is doing about 35mpg. Same speed, same car, same air resistance so they are producing the same power, but one is burning 25% more fuel to achieve it. What's happening?

As Ian said, the cruising fuel consumption would actually be much, much closer than that. Things like the age of the car would probably be more significant than the engine size (all manufacturers have improved engine efficiency over the years).

 

[Pcn1]

Are the 5 Litre V8's bullitt proof ? Do they need head gaskets at this age allowing for average mileage ? Are they cam belt or chain engines?

If there really isn't much in it for running costs then I would consider one

 

[kth286]

Forgive me for going off at a tangent but this discussion has in it a perfect example of something that has been bugging me for years.

Two SLs driving along the motorway side by side doing the same speed. One, a 500 is doing about 28mpg and the other, let's say a 300 is doing about 35mpg. Same speed, same car, same air resistance so they are producing the same power, but one is burning 25% more fuel to achieve it. What's happening?

Two major factors are:

1. weight difference

2. internal friction of engine, which is significantly more in a V8 engine.

 

[IanA2]

My 500 is a J reg, I've had it a few years now and have had to spend very little on it.

Chain.

 

[BTB 500]

Never heard of head gasket problems on the V8 (commonplace on the I6). As Ian says, they have a cam chain.

 

[BTB 500]

Two major factors are:

1. weight difference

2. internal friction of engine, which is significantly more in a V8 engine.

The small weight difference would have no significant impact on steady-speed mpg. It's true that more cylinders generally means more friction, but as a small percentage of total work expended I think the impact on cruising mpg would be slight.

 

[Pcn1]

Sounds like the 500 is a little gem of an engine. Not much difference in mpg ( I only do 8K a year split between 2 cars ) and unless you suffer a major component failure its a low maintenance engine.
I assume its 2 valves per cylinder?
If its a cam chain does that mean we are talking about a good old fashion push rod engine?

Thanks

 

[vincenz]

The small weight difference would have no significant impact on steady-speed mpg. It's true that more cylinders generally means more friction, but as a small percentage of total work expended I think the impact on cruising mpg would be slight.

Weight is a significant factor in MPG, but really between the two vehicles it may be at max 100kg

Internal resistance of extra cylinders, in theory yes but in the real world f all

Age of vehicle, yes again a slight factor but if its been well serviced it is only of small significance

The MPG boils down to the efficiency of the engine and power train,
Firstly you can get V6's that are more efficient than V8's and the other way around, no-one here has stated the efficiency of the 300 and 500 engines, from memory I think the most efficient internal combustion engines are only 40% efficient

Couple this with a drive train, at a given speed a V8 may be in a higher gear and lower revolutions than the V6 and vise versa giving a different output

So its not as simple as its burning an extra 25pc of fuel, change the speed and the 500 may return a better mpg than the 300

 

[ianbee]

The SL500 yr 97 in my opinion is a pretty awesome car. I got mine > 3yrs ago with 58K kms and 2 pevious owners. In Canada/NA this yr had the 4 vave heads w/4 overhead cams with a 5 speed auto. They reverted to a 3 valve desingn in 98 when the dreaded Chrysler bean counters got involved. It easily gets >30 mpg driven sensibly, approx 1700 RPM at 100kms. I have just turned over 80K kms with some problems. One very important thing to check is camshaft ticking noise at idle. There is an oil delivery tube system to each cam lobe that fails and improper lube is the result if not sorted asap, appprox $800.00 per bank to rectify, that's here where labour at a main dealer is "only" Cdn$100.00 per hr. My advice is to look for a good one, I wouldn't bother with the early 90's 4 speed ones though.

 

[IanA2]

I wouldn't bother with the early 90's 4 speed ones though.

They'll be the ones untouched by the beancounters then....