OM656 Failed Vacuum/Oil Pump and loss of braking.

[Jonathon Heap]

Good news !, hope you can enjoy the car again soon. Apparently mine is now going back together too, fingers crossed.

 

[moj91]

Mercedes called and i collected my car at the weekend, done roughly 100 miles since then. Seems ok, bar an engine bay rattle and it pulling to the right. So i will be popping back in to discuss this with the dealer in due course.

 

[captainkirk]

I thought i had better write up my current situation with my 2020 E400d. (December 2019 build date)

Bought the car in June, 1 year old.
Apart from the boot lid opening itself once in a while and a very occasional issue with the gear stalk not selecting properly (and the 20" wheels getting damaged too easily but that's another story) its been good.

However, mid-November, the car went into limp mode shortly before J15 on the M1 - engine sounded 'wrong' and, a minute or so later as i was getting off the junction, (this stretch is, still, being converted into a "smart" lol motorway, so absolutely no places to stop on the motorway itself) i lost servo assisted brakes quite suddenly, the engine then bogged down to a stall as i stopped at the traffic lights.

MB couldn't arrange recovery for SIX hours, so i was directed, as the car was still 'running', (it did restart after a while cranking) to drive the 7 or so miles home carefully . And believe me it was careful with effectively no brakes.

Car was inspected and recovered in the morning to Mercedes Northampton - after a few days and challenge to get a suitable courtesy car, the dealer called to inform me that the tandem oil and vacuum pump had failed. This at a minimum requires engine out to replace, along with all the associated vacuum components. I was aware of a few instances of this problem in Germany from german forum reports - but with the car under warranty i was less concerned.

No repair took place for the rest of November I kept being told this is due to lack of parts availability and employee sickness (believable) however, i also discussed with them that i expected the engine to be checked for mechanical damage caused by any potential loss of oil pressure.

Two months later the car is still sat in the same parking space behind the dealer, no work having been yet undertaken. Still being told that parts/labour are not available. I was told that i was 'lucky' the car is in warranty as this is 'going to cost at least £12k to fix'.
I do have an E220d estate though now as a courtesy car which is sufficient for the time being.

My issues are:
The loss of braking was certainly dangerous with an otherwise 'running' car, with the nature of the failure i experienced this could have been much more dangerous.
Two months in and no work has been started on the car. Has the dealer identified, i wonder, that the engine is also damaged and they are not telling me, hence the lack of correspondence and fact that the car hasn't moved in weeks? (It is visible from the access road to the retail park)

Can i reasonably expect to claim any compensation from MBUK? I'm paying Tax, finance and Insurance etc. on a car i have no use of.

How many other vehicles are affected by this pump issue? I note that another forum member 'Anko' is in the same situation, but just out of warranty and with a near £6k bill.

I have now reported this experience to VOSA as this absolutely is a safety recall trigger.

Thoughts welcome.

Hi Mo
I have the same car as you, July 2019 E400d estate. I’ve owned the car from new and have covered 30,000 miles.
Last week I got in the car to fill up with fuel and noticed straight away loss of power, as you are well aware these cars are normally rocket ships but mine had nothing.
I had to go away on business on the Saturday so I took my wife’s car.
Returned home on Wednesday night and called MB breakdown first thing Thursday morning where I was told to drive the car some 30 miles to my dealers.
I did this and the car would not go over 50 and wouldn’t change gear above 5th.
Left the car with them and got a courtesy car and I called today to get an update, like you I’ve been told it’s the oil tandem pump.
So I’ve googled this and now again like you I’m concerned about any other damage being done to the car.
Fortunately I’m still under warranty with 5 months left but I am concerned about the fact that this part should have failed at 2.5 years old with a mere 30,000 on the clock.
I welcome any other info you have please.
Kindest regards

 

[Jonathon Heap]

My E400d All Terrain has been with Mercedes since Jan 4th for the same issue. I believe the pump is now sorted but they are now having issues with the fuel injection. Hopefully I'll see it again soon. The tandem pump issue is very common I have been informed.

 

[captainkirk]

Hi Jonathan

I spoke with my dealers this afternoon, they have the pump in stock and are just waiting for some other parts that are needed when the engine is stripped down.
Hopefully I will get an update on Monday.
I intend to keep the car as I do love it and it has been the best Merc I have ever owned and I have had a few. I do intend to buy the Mercedes’ extended warranty in July when the car will be three years old, hopefully I won’t need it but you never know.
Cheers
Geoff


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[Jonathon Heap]

It might be cynical, but what you say is exactly what I was told. Waiting for parts, pump arrived, waiting for 'bolts' and now fuel injection issues. Unfortunately , to fit the pump, the engine and box are removed from the car, so its a big job, ( £4.5K's worth I was informed ). I'm wondering now if the pump was the problem, or that Mercedes are simply throwing parts at it until it works properly. It was suggested that its been shipped back to Germany to be sorted properly, by one of my work colleagues. Apparently his friend had a tracker fitted to his Merc and wondered why his car was no longer in the UK, a few red faces I think. Still benefit of the doubt and all that. I too love the All Terrain, and would have kept it , had the Marco Polo not been seen as a solution to our holiday aspirations. Just hoping that the Marco Polo doesn't have a poor reliability record.

 

[Jonathon Heap]

Collecting the fixed E400d tomorrow after its marathon warranty work. Just hope its as good as it was before.

 

[Jonathon Heap]

Car collected, what a joy to drive it again !. Only slight hiccup, someone had decided to steal my number plates. Mercedes Solihull soon made up new ones and fitted them.

 

[DSK]

Car collected, what a joy to drive it again !. Only slight hiccup, someone had decided to steal my number plates. Mercedes Solihull soon made up new ones and fitted them.

I’d report it the police, get it on record, criminals do this to commit crimes whilst not getting caught, yet the one whose been cloned gets all the fines and knocks on the door.


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[sonic]

Car collected, what a joy to drive it again !. Only slight hiccup, someone had decided to steal my number plates. Mercedes Solihull soon made up new ones and fitted them.

Report it to the police, if stolen they will be used in crime. Police will put a marker on PNC so you might get stopped as well.

 

[Jonathon Heap]

All sorted thanks, called WM Police straight away and it's being investigated. Last thing I want is being stopped or getting a knock on the door.
The good aspect of this claim however is that Mercedes have issued a full recall on all 400d engined cars. At £4.5 - £12.8k per car its going to cost them dear for a relatively cheap component, which is clearly poorly designed. As a recall I guess all cars outside of a warranty will be fixed FOC, wonder if those who have had to pay will get a refund ?.

 

[Jabez]

My E220 2019 was just out of warranty when engine warning light came a week ago. I immediately booked with Mercedes for a check which costs ca. £300. Yesterday, the diagnosis revealed that there is an oil and coolant leakage to the tandem oil/coolant and vacuum pumps. I was told that this may cause the vacuum brake servo to fail at any moment and thus the brakes. Preliminary estimate of the cost for the repair is in excess of £10k with two months waiting time (as they are fully booked). They explained that they will have to remove the engine to replace the damaged oil/coolant and vacuum pumps and associated components thus it is a 3 or more days job. I do not feel any performance or braking issue with the car but I am now afraid of driving it as I often have to drive on motorways. I have no possibility of paying this much for the repair as I just bought it from the first owner less than 2 months ago. The thing is the car is my livelihood as I drive it as a taxi and it has 300 000km in just 3 years which is normal for a taxi. I live in Sweden and here most taxi cars from other car makers reach 300 000km without problem but Mercedes or Volvo cars are preferred (despite their hefty prices compared to the other brands) as they are believed to go much further without major issues.

I just read a security alert by Mercedes which I believe is to be related to these issues. It is not a recall but I am wondering whether to contact them as this clearly is a 'design' and not a 'wear' issue. What do you think?

Safety Gate: the EU rapid alert system for dangerous non-food products

ec.europa.eu

 

[Phil2]

My car has the same problems described in these posts - namely loss of power and car stuck in gear or inconsistent gear changes, over-revving, manual paddles stop working. MB have just told me that the Tandem Oil and Vacuum Pump needs replacing. Thankfully the car is still under warranty but reading these posts it sounds like I will be without it for a little while. I just wanted to ask if the repair has fixed the problems that you were having and your car is now running well - Jonathan your issues sound identical to mine as it was all transmission based and the brakes were not affected. I have 6 month warranty remaining and I'm minded to trade this is in before it expires.

 

[Jonathon Heap]

The warranty work has returned the car to as good as it was before. Few niggles, as in low coolant level, which should have been sorted after a road test and a rattle in the dash. Car works perfectly though and is again a joy to drive. My warranty is almost up now, so I will buy an extended warranty for 12 months to help the new owner , as I will be selling the car in a few months when my new one arrives

 

[Phil2]

The warranty work has returned the car to as good as it was before. Few niggles, as in low coolant level, which should have been sorted after a road test and a rattle in the dash. Car works perfectly though and is again a joy to drive. My warranty is almost up now, so I will buy an extended warranty for 12 months to help the new owner , as I will be selling the car in a few months when my new one arrives

Thanks Jonathan. That’s good to know. I’ve had Mercedes for 10 years and I’ve always found them reliable but in last 6 months I’ve had a tail light replaced. A new master cylinder and then this. I do like driving the car and don’t particularly want to change it so I will look into the extended warranty.

 

[Jonathon Heap]

I've had, 5 E class cars and only really replaced tyres and drop links . They have been the best and most reliable cars I have owned, even the first old ones costing less than £3k. The dual pump is not really too bad to replace, what makes it difficult and expensive is that you simply cannot get to it without pulling the engine and box. Had it been a 4 pot motor it would be replaced in a matter of hours. If you are happy with your car , I'd keep it, but definitely take out the Mercedes warranty and keep up the Mere servicing. It might not be the cheapest but it keeps you as parts of the assist package and long term body warranty. I think all cars can have problems at some point, but there is a perception that Mercs are better quality and its surprising that a unit such as the dual pump can be so poorly designed, both as a part and its placement .

 

[DSK]

My E220 2019 was just out of warranty when engine warning light came a week ago. I immediately booked with Mercedes for a check which costs ca. £300. Yesterday, the diagnosis revealed that there is an oil and coolant leakage to the tandem oil/coolant and vacuum pumps. I was told that this may cause the vacuum brake servo to fail at any moment and thus the brakes. Preliminary estimate of the cost for the repair is in excess of £10k with two months waiting time (as they are fully booked). They explained that they will have to remove the engine to replace the damaged oil/coolant and vacuum pumps and associated components thus it is a 3 or more days job. I do not feel any performance or braking issue with the car but I am now afraid of driving it as I often have to drive on motorways. I have no possibility of paying this much for the repair as I just bought it from the first owner less than 2 months ago. The thing is the car is my livelihood as I drive it as a taxi and it has 300 000km in just 3 years which is normal for a taxi. I live in Sweden and here most taxi cars from other car makers reach 300 000km without problem but Mercedes or Volvo cars are preferred (despite their hefty prices compared to the other brands) as they are believed to go much further without major issues.

I just read a security alert by Mercedes which I believe is to be related to these issues. It is not a recall but I am wondering whether to contact them as this clearly is a 'design' and not a 'wear' issue. What do you think?

Safety Gate: the EU rapid alert system for dangerous non-food products

ec.europa.eu

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I feel for you especially when your car is what puts food on the table for you! The mental stress I can only sympathise with. So many people buy Mercedes because they think its quality but only the odd model is a quality item in this day and age, the good stuff Mercedes stopped making a long time ago!

As you are in Sweden I am not sure of the laws but, I would strongly suggest speaking to a specialist motoring lawyer who is experienced in dealing with cases where a product is not fit purpose. Also the new Volvo's are not as reliable as the old ones so be warned!

 

[moj91]

I've been quiet for a while - basically just assessing the car for a month.

I've noted since getting it back it seems down on power and seems to be returning a notably lower MPG on long runs. I did a 200+mile trip on Sunday, expecting around 50mpg, struggled to get 40mpg.

I also keep getting a 12v battery warning - i suspect the car being sat/moved around for 3 months has killed the battery. I've done nearly 2k miles since getting it back - plenty of time for it to recover if it will. Still also having issues with the gear selector stalk not reacting or sticking the car in a different gear to the one selected.

I've also been chasing the dealer for a copy worksheet/invoice for the scope of the repairs. They keep failing to provide one. I demand one for my own records considering the significant repair.

 

[Jonathon Heap]

Sorry you are having additional issues with your returned car. Maybe I had a good crew or am just plain lucky that my only issue has been low coolant. Mind you my AT 400d has only returned 48mpg on a very conservative run, and normally averages around the 38-44 mark. I too asked for a list of works for my records and if I pass the car on. I was fobbed off so will chase this next week. I filled in a Mercedes questionnaire a while back and let then know how dismal I thought the customer relations has been ( for a premium marque) I did not receive a reply, but equally will not hold my breath for one. Hope you can get your current issues sorted and enjoy these great cars again.

 

[DSK]

I think you should be entitled to know what was done to the car upon request, as the customer, regardless of who paid the bill. Dealers always fob off but too many people just let them get away with their antics. Just contact Citizens advice, which is free and will take a few minutes. They will give you a ref number, then just write to the dealer quoting it and most likely they will give you the details of the work done. This is usually more than enough to get dealers to do 30 seconds of actual work.

However, with the complications of modern technology and generally poor materials I see, I'd expect the odd ongoing issues as what you experience as its only the quality of workmanship that will make the car run as it was before.