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1993 600sec AMG from Japan that I got in project type condition is finally getting some attention... I’m finally diving into getting some restorations done on the M120 engine first Then the electronics in the car ... I’ve written in previous posts... the engine starts right up everytime but makes a weird screeching noise when it fires... then idles high and stsys high ...
Then when at temp will idle up and down if you give it a good rev in park...
Drives not bad when cold but still high idle .. has a oil leak in the front near the oil cap on the engine and when I checked last year there was oil inside the hole where the spark plug next to the cap is... there is also a strong odor of gas most likely old fuel when the car is running... power steering isn’t working that well maybe just the power steering pump is gone, when u accelerate from a stop there is a banging/knocking sound felt from the middle of the car... I have a lot of questions anyone specialists on these cars pls chime in.

I’ve had a few ppl on the forum tell me to check the spark plugs and a few other tune up things that I will be getting to very soon but wanted to omow
How big of a project do I have on my hands.
 

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Banging underneath is likely either the center bearing mount on the driveshaft, or the flexible couplings at each end of the driveshaft, or both. Don't drive it until checked, because if driveshaft comes loose, it could do thousands of dollars of damage. It could also be broken exhaust hangers, but the symptoms sound like driveshaft.

Oil leaks around plugs means pulling the valve covers to replace gaskets, which means pulling the intake manifold. Vsandvs on YouTube has videos on that job.

High idle indicates vacuum leaks. Do a smoke test on the engine to find leaks. Again, vsandvs has videos on YouTube showing the process.

Screech may be bad bearings on idlers or various belt driven accessories at front of engine. Pull the serpentine belt and turn each item by hand listening for any noise. All bearings should be smooth and silent.

Any W140 and M120 with lots of deferred maintenance is a big project, but the rewards are worth it.

Jon
 

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Discussion Starter #4
Banging underneath is likely either the center bearing mount on the driveshaft, or the flexible couplings at each end of the driveshaft, or both. Don't drive it until checked, because if driveshaft comes loose, it could do thousands of dollars of damage. It could also be broken exhaust hangers, but the symptoms sound like driveshaft.

Oil leaks around plugs means pulling the valve covers to replace gaskets, which means pulling the intake manifold. Vsandvs on YouTube has videos on that job.

High idle indicates vacuum leaks. Do a smoke test on the engine to find leaks. Again, vsandvs has videos on YouTube showing the process.

Screech may be bad bearings on idlers or various belt driven accessories at front of engine. Pull the serpentine belt and turn each item by hand listening for any noise. All bearings should be smooth and silent.

Any W140 and M120 with lots of deferred maintenance is a big project, but the rewards are worth it.

Jon
Jon thank you very much...
 
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