Mercedes Benz 4.0 V8 Plastic Oil Drain Plug ? Replace or Re Use?

[daveatthebill]

Hi everyone,


I’ve got a Mercedes with a gas V8 engine that’s a few years old, and I’m planning to do the oil change myself for the first time. I stopped at the Mercedes parts counter in a nearby town to pick up what I needed, and the guy told me, “It says you don’t need a new plug or gasket” — just an oil filter.


When I got home and looked underneath, I saw that my car (and maybe other Mercedes models) uses a plastic oil drain plug. The one on the car looks like it’s in decent shape — no cracks, no signs of damage.


Normally, I’d just grab a new one to be on the safe side, but the dealership is a bit of a drive and I don’t want to go out there again unless it’s really necessary. Maybe the guy was right and I’m just making a molehill out of nothing.


Still, I wanted to check with others who have done this before:
Is it safe to reuse the plastic drain plug if it appears fine? My logic is that if it’s been holding oil all year without leaking, it should still be good — but maybe the concern is the seal or O-ring wearing out from removal?


Is this one of those “replace every time” parts, or can I confidently reuse it if it looks okay?


Thanks in advance for your advice!

 

[ka9mnx]

Plastic drain plug? Wouldn't be my first choice but I'm not a MB engineer.

 

[shortyb]

A plastic drain plug?? Oh no! Keep the plug, but replace the rest of the car.

Seriously, you'll be fine for a couple changes with the plastic one that has the o-ring. Get a couple to keep on hand next time you're at the dealer in case one starts to weep on you.

 

[Astro14]

What year and model?

Does Mercedes specify draining the oil through the plug?

Or by extracting it with a vacuum extractor?

 

[Marcozi]

Plastic drain plug? Wouldn't be my first choice but I'm not a MB engineer.

Yup, that plastic drain plug save 0.3255g of weight! /s

 

[Cujet]

While I've never had any plastic drain plug failures, I know that there have been a good number of 'oil loss' events related to plastic drain plugs. Most of the time it is degradation of the plastic and the o-ring then fails to seal. Leading to a stream of oil down the road and if not caught in time, low oil pressure.

I am very glad my new F150 has a conventional drain plug.

 

[Dr_Dr3i]

+1 on post #4

Pretty sure most MBs are serviced via top-side extraction, therefore the drain plug should not be seeing any "use".

 

[andyd]

Can it be replaced with a metal plug? Or does it snap in? Oh well, I don't like 0W20 either. How much is an extraction thingy? Ive got 50$ tied up in special use Camry oil filter tools, so I can relate.

 

[daveatthebill]

What year and model?

Does Mercedes specify draining the oil through the plug?

Or by extracting it with a vacuum extractor?

My apologies it is a GLC 63 AMG, they do not come with a dip stick or anywhere to suck fluid from in this model. Other model's do get sucked since they have a dipstick portion I was told.

 

[daveatthebill]

My apologies it is a GLC 63 AMG, they do not come with a dip stick or anywhere to suck fluid from in this model. Other model's do get sucked since they have a dipstick portion I was told.

 

[tcp71]

Euros love to "replace" every plug once you touch it. Every drain or fill plug on the Macan calls for one time use...transfer case, differential, gearbox, etc are all metric aluminum plugs with a one time use specification. I would simply re-use it this time, get a spare in the future to have on hand along with a handful of replacement o-rings. As long as the plastic hasn't degraded or broken during removal, snap a new o-ring on there and move on.

Measure the o-ring and buy 50:

https://www.mcmaster.com/products/o-rings/o-rings-2~/oil-resistant-buna-n-o-rings-8/