[calumski]

Evening all,

I'm new here and in need of some help. I've just taken ownership of an 89 560SEL - beautiful car!

I only plan on getting the car MOT'd and then getting shot of it but therein lies the problem!

I've had a mechanic look it over and all looks sound apart from two main things - the vehicle idliing at 1600RPM which (after some extensive reading) I'm maybe thinking the ICV and secondly the suspension isn't rising.

Soooo. I'm reasonably handy with some tools and a multimeter and would like some assistance in diagnosing the suspension. From what I've read up on, it's SLS with the pull knob next to the lights.

Can someone point me in the direction of a good technical description of how to troubleshoot the suspension and how it works? And also where I should start with diagnosing the fast idle?

Just looking to get the car MOTd and get shot of it so I would appreciate it if someone could give me an idea of it's worth.

There's no service history, last MOTd four years ago and from what I remember, 110K on the clock. Bodywork in good condition apart from some rust on the offside front wing. 18" AMG wheels and all electrics working.

Thanks for the help in advance. It'd be good to talk to someone technical about the car so if you have some time and would like to help a novice (!), send me a PM please and I can give you a shout.

Cheers all,
Calumski

 

[et7724]

i think the high idle could be the overload relay (OVP relay); just search for that on here and you'll get lots of hits...can't help ya with the SLS; never worked on one; i would obtain the mercedes factory manual

 

[TalkieTime]

This is where I purchased my 126 Service Library, a copy of the 2 CD set from Mercedes Benz:

Mercedes Service Repair Manual SD SE SEC SEL All W126 | eBay

Other than purchasing the CD set, I have no connection to the seller.

 

[LongHauler]

TalkieTime, Does that CD set cover the 560 engine?

 

[bondavi]

If the car has a knob next to the lights as you say, you have the 4-wheel hydropneumatic suspension which is a different setup than SLS. Similar system to what was used on the w116 6.9's.

MB_Mike has experience on such a system from his euro 560SEL. But first, let's confirm what you have first.

You should also find a switch on the center console above the climate controls that controls height adjustments. Also a pulley driven oil pump in the engine compartment.

Do you find these items?

 

[calumski]

OK, sorry for the confusion. Thought the SLS and the hydropneumatic were as one. I do have the knob next to the lights and also the ride height adjustment switch in the centre console.

So...

Where do I find the reservoir to see if the suspension is empty? And do I rish running it dry if there's no oil in there or is the same idea as aircon on the VW where there's an electric clutch that only kicks in if there's enough pressure in the system?

Thanks again...

ET, thanks for the info on the OVP, I'll go look.

 

[bielefeld280se]

Hi, congrats on the car first of all! Nice to see another member from Scotland on here as well. Any pics of the car?

As for the idle, might be best to taking your ICV out and giving it a clean up with some carb cleaner. Pretty easy to get at. I gather a high idle can be quite tricky to diagnose sometimes. Also if you need second hand parts I can recommend Rob Parker Three Pointed Parts

If you stuggle with it yourself, there are a couple of garages I can recommend in the Glasgow area that know old Mercs.

 

[ianrandom]

The idle should be easy enough to get down. OVP sounds about right at that idle speed.
Suspension might be a bit trickier, very cool option though so i hope it works out for you.

 

[mramay]

The high idle can also be an open in the Idle Control Valve (ICV) solenoid. Pull the plug and read it with an ohmmeter. It should be under 10 ohms, IIRC around 4 ohms. If it's open, no resistance reading, then it's bad. The ICV can generally be repaired so if that's the problem, don't go spend a lot of money on one yet.

 

[TalkieTime]

TalkieTime, Does that CD set cover the 560 engine?

The set was originally produced by Mercedes Benz North America. It includes most everything except transmission repair/rebuilding. This set would be helpful for use with North American and European models but is specifically for NA models so it doesn't address differences between NA and European models.

 

[ianrandom]

^ Yeah tool me ages to realise why certain stuff isnt right for my car in those service CD's. Its just that some of its different on Euro cars.
They're still extremely useful though. Do they have the full hydro suspension in them though? Cant remember.