Ian Donkin
Active Member
I needed the glow plugs changing on our E-class (mines the OM642 V6 variant) and out of convenience entrusted the work to a mechanic in my local village as opposed to travelling out. I’ve previously seen him rebuild a customer’s Merc 3.0 V6 petrol when the bearings failed and he’s always working on expensive cars, so I believe(d) him to be highly competent.
Long story short with my job, one of the glowplugs had taken a permanent fancy to the surrounding cylinder head that necessitated the removal of the left bank and subsequent machining to remove all the debris - not exactly the sort of costs anyone would wish to incur to change a £10 part, but I was assured that everything had come apart without difficulty and all the components (turbo, timing chain, cams, cylinder bores, pistons, injectors, valves, inlet manifold and flaps, etc.) were perfect so at least I felt happy that everything was otherwise good.
Almost three weeks later my car was ready and now had a sound at tickover rather like a family of crickets having a party around the aux belt area. Once the aircon was turned back on however the sound disappeared, so this noise was attributed to the compressor and I was dispatched on my way (it must be all of 800 yards back to my house).
I turned on to our private road and gave the throttle a prod only to be met with the sound of a boost leak so back to the mechanic we go. I should also note that the pipe from the turbo to the intercooler didn’t look right as there’s now a ‘shiny’ section where the turbo and pipe join together and it looks out of place with the patina on the rest of the aluminium in that area. I suggested that this couldn’t be right and the mechanic agreed, but pointed out that as everything could only fit in one place (fixed bolt holes etc.), it must be correct.
Two days later I get my car back again with a new seal fitted in the aluminium pipe from the turbo to intercooler, but it still felt both laggy and a little flat when accelerating, plus I now could hear a turbo whistle for the first time as it started to produce boost. There’s still a section of exposed shiny metal and the plastic air intake from the filter housings is now broken at the turbo end, so a part of the seal is visible between the jubilee clip and body of the turbo.
Breakages aside, the mechanic had already suggested it didn’t feel right, but to drive it and see what I thought. Fortunately I’d recently had a Surrey rolling road session so went back and sure enough, the car was around 50ftlb down on torque and the plot lagged the previous runs by around 400rpm – boost leak came back the observation from Charlie.
Back to the mechanic for another day and the leak (found where the aluminium pipe connects to the plastic / composite pre intercooler, that hadn’t been seated correctly) is now rectified and I finally have a lively car. However, driving the same 800 or so yards home I experienced a new noise that transpired to be the undertray scraping along the road with three of the four securing bolts missing. To say I’m starting to lose my patience at this point would be an understatement.
A quick fix later and an uneventful commute to work and back the following day I had managed 50 or so miles with the car since the rebuild however it’s back with the mechanic as the mother of all metallic rattles that can be heard over everything else has suddenly started around the fuel pump / timing chain area. He’s offered to pull the fuel pump, investigate with a camera and report back.
His bill included 15 hours labour by the way and I understand the book time for a cylinder head removal / refit is 10 hours so I don’t think he’s been short of sufficient paid time to do the job properly.
Looking to the positives (!) the O2 sensor replacement also carried out (all MB parts were used throughout the job) has removed the dip in the torque curve after peak that my first rolling road session highlighted and the exhaust is less sooty (so much as it can be after 50 miles).
I’m pretty sure this saga isn’t over yet, but what are the collectives thoughts here. Are there lots of specialist tools needed to complete this job that I can ask him to show me (as proof he was correctly geared up to the task), or specific alignment procedures for the timing chain / tensioners / cam sprocket, etc. that he could have got wrong?
I’ve already paid (on the one day it seemed good) and by bank transfer so I can’t leverage a s.75 claim with my credit card, but what is the likelihood that having given him a car that he acknowledged was in such rude health on handover, I should now have problems that I can only believe are related to the work he has done in the same area of the car?
Any appropriately qualified input would be appreciated.
Long story short with my job, one of the glowplugs had taken a permanent fancy to the surrounding cylinder head that necessitated the removal of the left bank and subsequent machining to remove all the debris - not exactly the sort of costs anyone would wish to incur to change a £10 part, but I was assured that everything had come apart without difficulty and all the components (turbo, timing chain, cams, cylinder bores, pistons, injectors, valves, inlet manifold and flaps, etc.) were perfect so at least I felt happy that everything was otherwise good.
Almost three weeks later my car was ready and now had a sound at tickover rather like a family of crickets having a party around the aux belt area. Once the aircon was turned back on however the sound disappeared, so this noise was attributed to the compressor and I was dispatched on my way (it must be all of 800 yards back to my house).
I turned on to our private road and gave the throttle a prod only to be met with the sound of a boost leak so back to the mechanic we go. I should also note that the pipe from the turbo to the intercooler didn’t look right as there’s now a ‘shiny’ section where the turbo and pipe join together and it looks out of place with the patina on the rest of the aluminium in that area. I suggested that this couldn’t be right and the mechanic agreed, but pointed out that as everything could only fit in one place (fixed bolt holes etc.), it must be correct.
Two days later I get my car back again with a new seal fitted in the aluminium pipe from the turbo to intercooler, but it still felt both laggy and a little flat when accelerating, plus I now could hear a turbo whistle for the first time as it started to produce boost. There’s still a section of exposed shiny metal and the plastic air intake from the filter housings is now broken at the turbo end, so a part of the seal is visible between the jubilee clip and body of the turbo.
Breakages aside, the mechanic had already suggested it didn’t feel right, but to drive it and see what I thought. Fortunately I’d recently had a Surrey rolling road session so went back and sure enough, the car was around 50ftlb down on torque and the plot lagged the previous runs by around 400rpm – boost leak came back the observation from Charlie.
Back to the mechanic for another day and the leak (found where the aluminium pipe connects to the plastic / composite pre intercooler, that hadn’t been seated correctly) is now rectified and I finally have a lively car. However, driving the same 800 or so yards home I experienced a new noise that transpired to be the undertray scraping along the road with three of the four securing bolts missing. To say I’m starting to lose my patience at this point would be an understatement.
A quick fix later and an uneventful commute to work and back the following day I had managed 50 or so miles with the car since the rebuild however it’s back with the mechanic as the mother of all metallic rattles that can be heard over everything else has suddenly started around the fuel pump / timing chain area. He’s offered to pull the fuel pump, investigate with a camera and report back.
His bill included 15 hours labour by the way and I understand the book time for a cylinder head removal / refit is 10 hours so I don’t think he’s been short of sufficient paid time to do the job properly.
Looking to the positives (!) the O2 sensor replacement also carried out (all MB parts were used throughout the job) has removed the dip in the torque curve after peak that my first rolling road session highlighted and the exhaust is less sooty (so much as it can be after 50 miles).
I’m pretty sure this saga isn’t over yet, but what are the collectives thoughts here. Are there lots of specialist tools needed to complete this job that I can ask him to show me (as proof he was correctly geared up to the task), or specific alignment procedures for the timing chain / tensioners / cam sprocket, etc. that he could have got wrong?
I’ve already paid (on the one day it seemed good) and by bank transfer so I can’t leverage a s.75 claim with my credit card, but what is the likelihood that having given him a car that he acknowledged was in such rude health on handover, I should now have problems that I can only believe are related to the work he has done in the same area of the car?
Any appropriately qualified input would be appreciated.
