1978 240d Mercedes clutch

When I depress the clutch, there is absolutely no tension and the pedal doesn’t spring back up. In order for it come off the floor, it needs to be physically pulled up.

It’s time to have the clutch hydraulic system inspected for leaks, either internal or external.

Is there any hydraulic fluid in the clutch reservoir?

I haven’t checked the reservoir yet. Truthfully, I don’t know much about cars. But I’m taking my car to the mechanic tomorrow and want to know what he should be looking for.

In addition, is there any way an oil spillage in the engine area have an effect on the clutch hydraulic system? I took my car in for an oil change and the mechanic left off the engine cap. By the time I noticed, engine oil had spewed out the top of the engine hitting the engine hood. This created a rain of oil all over my engine, seeping out of the headlights and grill. (I’m taking it to a different mechanic tomorrow.)

Your first step should be inspecting the engine oil level. If it’s very low you do NOT even want to start the engine up at all.
If the oil level is not showing on the stick it’s possible that you could have some engine damage; depending.

Take some pics of this, document everything, and hit up whoever did this oil change about this mistake.
It could be that they owe you at a minimum a free oil change and auto detail job or something far more serious - engine damage.

I would be hesitant to allow whoever caused this mistake to be the one to inspect it. Their agenda could be to simply whitewash any engine problems or extremely low oil level and tell you everything “will be just fine”.

As to the clutch problem it does sound like failed clutch hydraulics and not likely related to the engine oil leak; unless this was an oil change facility and someone topped off the clutch fluid resevoir with something that should not be in there.

Unlike some cars, your MB engine will throw A LOT of oil out where the cap should have been in short order. I think ok4450 has a good point. If the clutch failed right after that incident, I’d say the wrong fluid (eg oil) may well have been added to the reservoir. I’m guessing it was an “iffy lube” type of place. It wouldn’t be the first time. If that’s the case, ALL of the clutch system hydraulics will have to be replaced. It won’t be cheap, but it should be at their expense.

I’ve had a coouple of 240Ds, but it’s been a while back. I don’t recall if they use the same reservoir for both the clutch and brake systems. If they do, or you find oil in that reservoir too, then your brakes will take a dive next.

That’s a good point. I took a quick look at the parts listing for Benz hydraulic cylinders and it appears they use a common resevoir for both clutch and brake cylinders. SAAB is the same way.
Hopefully, engine oil or whatever has not been added to the resevoir but if a quick lube was involved, who knows.

Just an example of how touchy that stuff can be, I screwed up a clutch master cylinder rebuild on a SAAB one time over a foreign substance.
I had the cylinder diassembled on the bench, honed, etc. and ready to go back together. Someone called me off the job and when I returned to it 30 minutes later, and being in a hurry, I washed my hands off in the parts washer. Wiped them dry with clean shop rags and reassembled the master cylinder.

The clutch worked great - for about 10 minutes. After taking it back apart, and doing some serious brain wracking, it came to me that what happened was that when I assembled the new seals onto the cylinder piston I had traces of mineral spirits on my hands from the parts washer tank.
Those faint traces of mineral spirits rubbed off on the seals and swelled them up horribly along with seriously softening them.

I had stared at those foam-rubbery 50% larger now seals for 15 minutes before it hit me as to what happened. Valuable lesson learned; soap and water on things like this.