Cliff Hunt

I have searched and read all threads I could find on here - I apologize if someone has had something similar and posted, I didn't find it, and appreciate any help, suggestions.

I have an 08 GL320 with approximately 200k miles.

About 5 mos ago, my problems began. Normal city driving, heard what sounded like an exhaust leak. Come to find out, right exhaust manifold was leaking around the flange. Replaced it. Car suddenly drove horrible with surge from 1200-1800 rpm under very light throttle ONLY AFTER REACHING OPERATING TEMP. Like clockwork, when vehicle reaches 100C (or is it 110?), the surge begins under light throttle. At Highway speeds, engine is like silk. Early on, also had constant high idle 800-1000rpm, that disappeared after replacing AC Compressor (and assorted AC components). I also *seem* to have frequent DPF regeneration, although Xentry shows DPF fine.

NO CODES w/ OBD or iCarScan MB
After reading multiple posts, I replaced:

• EGR Valve
• Exhaust Back Pressure Sensor
• Coolant temp sensor
• DPF Differential pressure sensor
• Throttle Control valve (did have a code in Xentry for this)
• Fuel Injection Pressure Regulator (showing possible issue, disappeared after replacement)
• Fuel Rail Pressure Relief Valve (showing possible issue, disappeared after replacement)
• Hi Pressure mechanical fuel pump (pressure seems fine now)
• Injectors on Cyl 1 and 2 (other 4 showed ok)

Both intake manifolds and swirl valve motor were replaced about 50k miles/3 yrs ago.

Any help? Local dealer is absolutely worthless. My very competent independent has been methodical, but he too seems stumped right now. All parts were quality OE/OEM parts - no cheap third party parts.

Thanks,
Cliff

Congocoles

Did you ever manage to fix this?
I'm having the same issue seems to be right on 1600 rpm but not constant with the gears and clears over 2000rpm, I have replaced turbo actuator and I have ordered an exhaust pressure sensor, I serviced the gearbox and replaced the egr valve with a Chinese cheap one and it seems to be doing it since then but hard to tell.

Cliff Hunt

yes, I did. so, similar to everything you did. changed at least 5-10 sensors, along with high pressure pump, various pressure sensors and regulators, 2 injectors. after everything, was still doing it. replaced entire turbo with Garrett and oe actuator. smooth as butter again. of you open the actuator, you will see there is like no return path to tell the ecu what it is doing. the one one communicates back to the ecu. there is a delicate balancing act. between fuel, air, ecu and turbo. I wasted 9 months and probably 3 or 4k before spending 1100 on a new Garrett turbo. I found dwdiesel had the. best price on Garrett. good luck! I also have a 2007 e320 w211. it had a Chinese actuator for last 3 yrs and had no problems, then aonth after the gl320, the turbo went on the e320. same replacement and it worked fine. go figure.i think the Chinese actuators are good for awhile, but then the problem becomes insurmountable and you must replace the turbo. both failed around 200-205k. literally within 5k of each other.

Congocoles

Thats great information thank you very much!
I have been leaning towards a new turbo but didn't want to spend all that money for it to just be a sensor but I will now take the plunge. I have in the last 1k miles had to deal with oil cooler seals/ snapped glow plugs which lead to one of the heads being replaced, swirl flap linkages, then the egr packed up and then within a few hundred miles it started this new fault. so a new turbo it is, thanks again!

Cliff Hunt

so, lastly, can't remember if this was in original post or not,but first I tried an aftermarket turbo, installed and same issues (think Chinese actuator). had to uninstall and return.
do yourself a favor, and only get the new Garrett turbo.... unless you can find a good low mileage used one that is compatible AND has the OE Hella actuator.

Congocoles

I have bought a reconditioned genuine mercedes Garrett turbo from a company but it's arrived today and it has a Chinese actuator fitted to it which I'm not to impressed about so it looks like I will now have to buy another one! Thanks for your help!

Cliff Hunt

So, I went down same path - and had to pay for install/removal of first with Chinese actuator. You would be better finding a low mile used one, if possible. The Garrett website has a LOT that are compatible. I am not sure where you are located, but they are out there used. I would just suggest if you intend to keep the vehicle for a long time, get the OE new Garrett (they weren't interested in selling reman Garrett, although according to Garrett they exist). Mine came from: https://dwdiesel.com/home - their website is not so hot, but I emailed them back and forth and the product and price were better than I could find anywhere (US anyway). I chatted with another guy who had similar issues with an S320 in Amsterdam, and the price he paid, incl VAT was less than the US price. His issues were the same, and the turbo resolved his issues, which is why I finally broke down and did it.

The day I picked mine up with new turbo, the mechanic had an article in a trade publication about why turbos fail in diesel (carbon buildup, lubrication of bearings - later diesels had an oil line run to them, and extreme heat). I am still waiting to tear mine down and inspect the cartridge. But, that return of data to ECU must be critical when the turbo gets older - maybe it gets stuck open or closed and doesnt respond to the actuator movement as cleanly. My arms on both my OM642 actuators moved freely, but both failed around 200k.

Hang in there!

Cliff Hunt

One more thing, if you can send me your VIN, I can look up the correct turbo for you from Xentry. Garrett's website is here for ML280. https://www.garrettmotion.com/turbo-...Z&vModel=ML280

Not sure if it works in GB. For mine, I had one Mercedes p/n stamped on the turbo. The dealer said that P/N did not exist (yet it does exist in Garrett). The Garrett part number was helpful, but then later on I realized that really any of the turbos that they list as compatible should work. If you have the Garrett part number, I can help you with that also. I actually took all their online education hoping to better understand why my car was having issues. Didnt really help, but it was interesting. Somewhere they have a chart for deciphering their part numbers. Found it: scroll to end, it was helpful: https://www.garrettmotion.com/turbo-...dentification/

Congocoles

Hi, I'm in the UK and I have found quite a few used turbos but I am unsure as my turbo seems fine on inspection no major play in Shaft and no loss of oil and like you said the actuator arm moves freely so I am a bit dubious to buying a second hand one thats why I bought a reconditioned unit but not knowing it had a copy actuator, I have removed the cover of both the genuine hella actuator and the Chinese copy and like you mentioned they're totally different internally. My vin is wdc1641202a3638230 and it would be much appreciated if you could tell me exactly which turbo I need if you have the time. We really love the vehicle for its engine and transmission combination but after chopping in both our land rovers this year due to unreliability I was hoping the mercedes ml would be more reliable but maybe I bought it at the wrong time and it's all gone wrong at once and now it will be more plain sailing. I will take a look at the Garrett turbo link , thanks for all your help.

Cliff Hunt

So, it seems Mercedes may only publish data in the US on vehicles that were available here. Your VIN comes back as unrecognized in Xentry (their parts platform). Best bet at this point is to get the Garrett part number (like 765155-5008 or GTA5006VK) and check it in the Garrett account. Do not rely on the Mercedes p/n (A642....) Attached image is plate from one of mine. The p/n 764381-2 - the 768381 is relevant. The 5002 (or simply -2 in the etching) part is not as important. The A6420900980 was not relevant really. This one is from an E320, but, the GL320's Mercedes part number did not exist according to Mercedes. If you find me that part number or want to send me a photo, I can help find it. Wish the VIN lookup worked.
I did find this in a European EPC. The last p/n is current. None of those 4 resolved in Garrett's website - so I think you will need to look at the plate on the front of the turbo.
5 A6420900780
Replaced By: A6420902080 1 TURBOCHARGER

5 A6420902080
Replaced By: A6420904780 1 TURBOCHARGER

5 A6420904780
Replaced By: A6420905980 1 TURBOCHARGER

5 A6420905980 1 TURBOCHARGER

Turbo plate photo OM642