Please help - 2012 ML350 Bluetec Oil Leak
12-22-2020 | 02:26 PM
#26
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Joined: Dec 2020
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ML350 bluetec sport
Oil leak on ML350 bluetec sport.
Hi. We have the same problem in our car. The mercedez garage said first that they have to change the fuel cap and the gasket that's their finding but not even a day and the problem is still there. So how they said it's the turbo charger. Its so frustrating because we have paid nearly £500 for changing the fuel cap and gasket and now we are going to get charge again for more God knows how much. It's ridiculous how much they charge for the labour £140/he.
Thanks guys for the input. I’ve cleaned the bottom of the oil pan as suggested. If it’s the oil cooler seal, where exactly should I be looking for the leak? How does the oil cooler seals leak from the back of the engine? I called a mechanic and he suggested rear main engine seal which requires the transmission to be dropped - is that even a common leak for these vehicles?
Cheers
Cheers
12-22-2020 | 04:04 PM
#27
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Joined: Oct 2009
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former- 10&14 ML BlueTecs, 20 GLE450 E-ABC, 15 Cayenne D, 17 Macan
The most likely culprit are the oil cooler seals, and yes, the oil runs down the transmission bell housing. While the third revision of the seals - the first ones made from Viton - was introduced in 2011, MB was still using whatever old silicone-based 2nd gen seals they had in stock at various production plants well into 2013 (I've seen 2014 MY MLs with the old 2nd gen orange seals). The 3rd gen seals are less likely to fail but they still do. The fourth gen seals (also purple Viton but with a larger surface area) were introduced last year. Regardless of where you get this serviced, make sure you get the 4th gen purple seals... the aftermarket ones are even worse than the orange ones.
Sometimes, when the air cleaners are changed, those seals can be crushed upon re-installation. The seals SHOULD be replaced when they are disturbed, but that may not have happened.
12-22-2020 | 11:35 PM
#28
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From: Toronto, Canada
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, C5 Z06 & IS300 race cars, EQE 4Matic+ on order
Hi. We have the same problem in our car. The mercedez garage said first that they have to change the fuel cap and the gasket that's their finding but not even a day and the problem is still there. So how they said it's the turbo charger. Its so frustrating because we have paid nearly £500 for changing the fuel cap and gasket and now we are going to get charge again for more God knows how much. It's ridiculous how much they charge for the labour £140/he.
While the turbo feed (pedestal) can leak, there's a good chance that it's not the turbo feed but the the oil cooler seals. Both are known issues with the OM642 engines in the ML350s, but the oil cooler seals are usually the culprit. I don't know how much faith you have in this shop (dealership? independent? Mercedes specialist?), but based on the first diagnosis and attempted repair that didn't work, I would definitely ask a lot of questions first. If they can't positively convince me that they know these specific cars, I would take it elsewhere to someone who specifically knows their way around a diesel ML350.
Agreed. Seeing as it is a rather laborious process and involves taking apart and removing a lot of stuff that's in the way, I would change every seal on everything in the way as a matter of routine. There are ~25 gaskets, o-rings and seals that Mercedes replaces during that job, not just the two $5 oil cooler seals. And, while they're in there, I'd also get them to change the fuel filter and PCV valve and replace both the oil and coolant. The cost of the new parts is insignificant when you take into account the cost of the labour, and they can prevent more costly repairs down the line.
