Well I am having oil consumption issues with my GL320 and think it is reaching the end of its life. I bought it in March 2020 and it is now sitting at 192,000 mi. For the last 10,000 I have used about 12qts of oil, maybe more. Motor runs fine, no smoke out the tailpipe but I think the dpf burns/filters it to the point there is no smoke. Motor runs great, no CEL, normal fuel economy, but consumes a lot of oil. In my start for a hunt for a new vehicle I wanted to log the cost of ownership and see maybe it's worth keeping and driving into the ground or selling as is to find something new. I would like another GL, but my wife who drives it, is leaning towards a mini-van. Sliding doors would be pretty sweet...anyway here's my ownership cost per mile to the best of my knowledge. We have put 34,224 miles on it and will be using that for the math. I DIY'd all repairs except oil cooler which was done with AEM. I'm factoring in the AEM payment along with what I am hoping to get out of the vehicle when I sell it/part out. Thought it may be helpful to someone.


09 GL 320 bought at 157,776mi - $8,250 / 34,224 = .24/mile


Sales Tax - $500 / 34,224 = .01/mile
3 yrs of Registration - $330 / 34,224 = .009mile
3 yrs of insurance (Liability) - $822 / 34,224 = .024/mile

Fuel - 34,224 / 20mpg = 1,711 gal x $3.89/gal = $6,656 / 34,224 = .19/mile (probably high)

Maintenance / Repairs
Oil Changes $60 x 6 = $360
Oil Cooler Seals - $650
Air Bags (Chinesium) $350
Air/Cabin Filters $100
Oil Filter Housing - $130
Tensioner, Belt, Idler Pulleys - $150
Tires (FB marketplace) - $200
DEF - $60
Extra Oil - $70
Transfer Case Chain - $150
Repair Total $2200 / 34,224 = .064/mile

AEM - $3590 / 34,224 = -.104/mile

Sell - $2000 / 34,224 = -.058/mile

Total cost of ownership / mile = $0.375 or about $12,834 to go 34,224 miles. Not great but, not horrible either considering its a MB?

 

those are great numbers considering it’s a diesel. I’ve got about $.15 a mile in maintenance on my GL 450.

 

Well I'm doing well maintenance wise until you factor in the cost of a new motor.

 

As you know, I commiserate with you. I feel your exact pain. As my 2009 R320 has the same exact oil consumption problem. I am facing the same agonizing decision as you. I think I will have to get rid of the beloved van.
I have no idea how much it would cost to repair piston rings. I definitely don't have time or expertise to DIY that kind of repair. Both of our cars either need new piston rings, or of course, it's probably cheaper to put in a used engine but that is another can of worms, because this problem appears rampant on om642, so who's to know if the used engine won't suffer from the same issue. I am also leaning towards dumping the beloved rhino wagon.

 

I think I'll do some magic in a bottle stuff and some heavier oil weights just for fun but yes I think our motors are unfortunately toast. It's such a shame as this thing has zero rust, especially for a midwest car that's 14 years old.

 

Hold onto it as a parts car for a newer GL450 and you'll come out ok.

 

We are thinking the same way.
I just ordered motul 5w 40 thicker weight oil, it is 229.52 approved, so I am also just going to give it a try and see if the thicker oil burns less. Currently I was using Mobil 1 5w30.

 

I have had excessive oil consumption for a long time, and figured out it is valve stem seals on the intake. I found LiquiMoly Hydraulic Lifter Additive slows the leakage considerably. I believe it does this by swelling the rubber seals.

Whether this will lead to other rubber seal failure due to wear, I do not want to think about.

 

Was the Mobil1 you used the "ESP" version? The ESP version is the special one that ia rated/recommended for the diesel. If the stuff you were using didn't carry the 229.52 rating, it'll be real interesting to see if just changing to the proper oil helps... I think/hope it will.

 

My 09 GL320 has about 200,000km and is having the same issue. I use about 1qt of oil with every fill up of diesel (600-700km). I installed an oil catch can but it mainly catches water and oil consumption did not change. It does keep the turbo intake free of oil residu. I can see elevated exhaust temperatures every other day or so (700C) for about 15-20 minutes using the torque scan app. That's when it probably regenerates and cleans the oil out of the DPF because I don't have smoke or leaks. Normally the exhaust temp is about 250-300C. You have cheap oil there for $60 oil change. I pay about $15cad for 1 qt (1L) of oil in Canada.

 

I have been using pennzoil euro L - 5w 30 which I have found at my local wallyworld for about $26 per 5 qt jug. It used to be about $22 when I first got the GL. It is the older 229.51 spec though which as I understand is not as good as .52 but eh. Then use a $8 hengst oil filter from FCP euro.

https://www.walmart.com/ip/Pennzoil-...uart/495194903

 

Look for the galon container sales of the mobil1 diesel at Canadian Tire. It's a lot cheaper than $15/qt. Granted I run the gasser, but a gallon is 34 but on sale. Or 60 some when it's isn't.

 

the insurance cost is only $140 for 6 month, that is super low.

 

about right for liability only.