W123 240D is getting a bit difficult to start
 

My daughters 1981 240D is becoming a little bit difficult start. After the glow cycle, I have to give it a tiny bit of throttle for it to start. Since I am entirely new to diesels I could only guess at the fix. The car is not down on power, it's not smoky and it runs pretty much perfect once it's started.

Any clues? I have a pretty honest mechanic, but I'd like to know generally what he will be talking about when I go there.

Thank you

Make sure the valves are correctly set.... always the first thing so you have a base line to go from.... they should be set once per 15,000 miles I think....

Basically the first thing as mentioned is a valve adjustment, and new filters. I'd also check to see if all the glow plugs are working correctly.

Do each thing and check for the results..
otherwise you will not know what fixed the situation the next time you have those symptoms...

You are aware of the idle set device on the dash? Set too low on some examples will hinder staring substantially.

Does a 1981 even have an idle set knob?

Try waiting 2-3 extra seconds after the glow plug light goes off... the timing relay for the glow plug light does not actually know when the glow plugs turn off. Wait a bit longer, see if that makes it easier to start...

I'm going to take a stab at your valves being too tight, or the cranking battery power being too low.

My Ford 7.3 liter V8 PowerStroke diesel absolutely will not fire if the cranking RPMs from batteries are too weak.

I'm not a mechanic either, BTW.

Yup..........all accurate.

Set valve clearance on a cooled off engine.

It has an idle set knob and I know how to use it. (Didn't have a clue WTF that thing was till the mechanic showed me)

I don't know when the valves were last adjusted, prior owner died and took that information and all the service records with him.

Been cycling the glow plugs up to three times before starting, doesn't help.

The battery seems to have plenty of cranking power.

Sounds like adjust the valves, change the filters then check the glow plugs if that doesn't get it done.

Thanks everyone.

I just noticed it's miles and color combo. If it's been garaged/cared for - you've got a definite lifetime keeper! I love that color Orient Red!!!

When I was 17 yrs old, my Dad bought his first MB. A new 1969 220D. Tobacco Brown. Auto Trans, AC. The first of several! :)

I switched to driving exclusively MB diesels in Dec. 1991.
The best, or nothing!!!

The car sat inside in a living collection for many years, it's a Knockout. The original owner babied this car, all repairs were done with OEM parts by a professional. There was no deferred maintenance whatsoever when I pulled the car out of the warehouse, just the vacuum trunk lock actuator needed replacement from sitting. It's a keeper, too bad I don't have a garage for it though.

I just looked at the only receipt I have, it shows the valves were adjusted in 2013 at 154,250 miles. I purchased the car in 2016 with 154,400 miles. Crazy huh? I didn't realize the valves had been adjusted, it's a small note on the work order.

I sold grey market MBZ new in the early 80s, not many orient red cars came through the dealer. I sure do like the color.

I would have loved finding a 220D for my kids, even slower!

Having to give some throttle to start it seems like a minor issue. Even recommended if the temp is cool outside.

LOL, so you're sayin' it's normal! Hahahaha! I like that answer best.