Interesting 'shims' letter in BMW Car Club magazine
- Thread starter mmm-five
- Start date
To cause a 0.2mm variation in the thickness of a 3mm shim would require a temperature difference of over 5000C, well beyond the melting temperature of the steel! To cause a 0.02mm (approximate tolerance range) difference in the shim would require approximately a 500C temperature difference. The issue is the dimensional stability of the whole head due to thermal expansion. Doesn't matter what temperature the shims are at, as long as they can be touched with the human hand without burning.mmm-five said:
When you put it like that it seems to make a lot more sense.So once again, it seems that the temperatures being perfect is not so important.
In absolute terms the difference between doing this in Norway in winter, and Dubai in summer, will be as large as the difference between a hot engine straight after a drive and it's resting temp in a hot country.
It seems fair to say that a car brought in at 9am and checked at 3pm or so, after all the other service items have been done say, would probably be fine!
Bringing it in the night before wouldn't SEEM essential, and so in itself not indicative of the job being done right. They might start the engine and drive it into the shop for a few mins adding enough heat to offset the overnight stay benefits for example!
I think as long as it's not done on a really warm engine (ie, left 3-4hrs) it is probably ok. That is probably what matters most, that big drop from near 100degC down to about 30degC approaching ambient temps where the cooling rate will drop right off (if it's about 20degC ambient in the workshop)
Dave
In absolute terms the difference between doing this in Norway in winter, and Dubai in summer, will be as large as the difference between a hot engine straight after a drive and it's resting temp in a hot country.
It seems fair to say that a car brought in at 9am and checked at 3pm or so, after all the other service items have been done say, would probably be fine!
Bringing it in the night before wouldn't SEEM essential, and so in itself not indicative of the job being done right. They might start the engine and drive it into the shop for a few mins adding enough heat to offset the overnight stay benefits for example!
I think as long as it's not done on a really warm engine (ie, left 3-4hrs) it is probably ok. That is probably what matters most, that big drop from near 100degC down to about 30degC approaching ambient temps where the cooling rate will drop right off (if it's about 20degC ambient in the workshop)
Dave
I imagine the reason for bringing it in the night before is so the car can be set up on the ramps and the work started on first thing in the morning with a cold engine.
I imagine its more a convenience thing than anything - as a dealer will be trying to fit xxx number of jobs in in one day, so having to wait for a car to cool down and/or move it into the workshop without starting would be a bit of a headache, although not impossible obviously.
I imagine its more a convenience thing than anything - as a dealer will be trying to fit xxx number of jobs in in one day, so having to wait for a car to cool down and/or move it into the workshop without starting would be a bit of a headache, although not impossible obviously.
Liverpool
The ambient temperature in any country does not matter one jot.Mr Whippy said:
What matters is that the engine and any other parts used in the measurement are at a consistent temperature when the measurement is done.
If you're in Dubai in summer at 40ºC, (hopefully not that hot in the workshop), then the car would need to be left in the workshop to get it's temperature DOWN to the ambient temperature of the workshop for the measurements to be relevant.
If you're in Norway at -40ºC (hopefully not that cold in the workshop), then the car would need to be left in the workshop to get it's temperature UP to the ambient temperature of the workshop for the measurements to be relevant.
In either case, if the difference between ambient temperature and engine temp is more than xºC then the measurements are useless.
If you simply drive the car straight into a service bay and measure the clearances of a 100ºC engine (Dubai normally doesn't get that hot unless there's a nuke involved) then they won't be measured correctly and the tolerances allowed by BMW will be out. If you let the car sit overnight in a 20ºC workshop (Dubai, Norway or Birmingham) then you have an engine which is likely to be at 20ºC, so the difference between different countries will be minimal.
If you leave the car in the car park overnight in Dubai, it might cool down to 30ºC or less anyway, but doing the same in Norway will bring it down to below 0ºC.
4 or less hours might be fine in the colder climates to get the car down to ambient temp, but in other countries it will take much longer.
The overnight requirement is not something the owner has made up, it's a stipulation from BMW. If the dealer's aren't following one simple rule then who knows what other simple rules they're conveniently ignoring.
If they want to charge me the non-///M price for an inspection then so be it and I'll live with the clearances not being done. But if they insist on charging me my ///M tax and doing them every inspection then I want to make sure they do it, by the book!
--------------------
They've done a similar 'bait & switch' on a warranty in the past where my car has had an MOT and failed on a leaking front strut. No problem I think, I've got MOT cover in my warranty which includes the suspension (as long as the car is serviced at BMW so that they can regularly inspect the warranted items). "Oh no" says BMW, the damper was only 'weeping' and therefore not covered "as they all do that sir" - yet the MOT FAILURE says 'LEAKING'.
So I had to buy 2 new EDC dampers at £600 each (plus springs, mounts, rubbers, etc) to get it through the MOT. Only after I'd got these items replaced and resubmitted for the MOT did the service manager state that the EDC dampers don't have to be replaced in pairs and their service adviser had got it wrong when she told me I needed to do them in pairs.
By the amount of bitterness and cynicism I have, what do you reckon their response was when I suggested some sort of recompense :thumbsdown:
--------------------
Despite spending on average £1500 every time the e34 went in for an inspection (2-3 times a year at about 12,000 miles between them) I've had services (obviously not all at the same dealer, as they'd get a couple of chances before I hightailed it to another, unfortunately equally useless dealer) where:
- there's been no (or very low) coolant in the system, despite the checklist showing the apprentice technician & supervising technician ticking the relevant boxes.
- the oil filler cap has not been fitted, and me ending up 10 miles from home with oil blowing out all over the car.
- they've not replaced oil, air, cabin filters.
- they've ignored my specific request to replace a leaking timing chain tensioner (emergency unfortunately, otherwise it would have gone elsewhere), and left the car on their ramps for 2 weeks with no sump on to 'investigate my leak' after I'd told them where the leak (1l per mile) was coming from.
- taken out my perfectly legal (and original) spare wheel & tyre and replaced it with a half-worn one (it was easy to see as I had 18" wheels on with a 17" spare and they'd put a 18" spare - not even an e34 one) back in (but I believe that time it was an honest mistake and they'd simply taken the spares out of two cars next to each other and picked up the wrong one when they went to put them back in).
I could go on, but even I'm starting to believe that BMW couldn't have been that bad and I've just made most of this up
But then I remember a certain dealer I've had problems with a lot more recently and realise some are still up to their old tricks (not David Holmes Stockport I might add, who've done a lot to help my on the path to forgiveness).
But as aerobod said, the variations are tiny within the range of temps given... fluctuations in temp from one part of the engine to another are probably bigger than those possible on a 'fairly' cold engine left for four hours... the engine isn't a homogenous object with a constant overall temperature.
I agree though, if the book says overnight, then overnight it needs to be, why else pay such large amounts. But I'm sure it's like that in the book to avoid any doubt on engine temperature.
Also, just from a 'reassurance' point of view, taking it in the night before doesn't assure it's not then driven the next day to get it into the workshop or something like that.
Totally agree on BMW shenanigans... if they try giving me any s**t I'll tell them straight that I won't ever be using them again and advising others to do the same. Bad garages, in any way shape or form, need to either sort their act out or shut up shop. There is NO excuse for being s**t!
Either do a job right or don't bother is my motto!
Dave
I agree though, if the book says overnight, then overnight it needs to be, why else pay such large amounts. But I'm sure it's like that in the book to avoid any doubt on engine temperature.
Also, just from a 'reassurance' point of view, taking it in the night before doesn't assure it's not then driven the next day to get it into the workshop or something like that.
Totally agree on BMW shenanigans... if they try giving me any s**t I'll tell them straight that I won't ever be using them again and advising others to do the same. Bad garages, in any way shape or form, need to either sort their act out or shut up shop. There is NO excuse for being s**t!
Either do a job right or don't bother is my motto!
Dave
LOLeasty027 said:
aerobod, interesting info you have posted.
Just had inspection 1 done. The mechanic came out to discuss the car/issues with me while I was picking up the hire car. He ran the engine to listen to it 'hot'. He then put it into the workshop while I was there so it was ready for work in the morning. 
He said he thought it sounded fine and that a little tappety was good in his opinion. 'Rather have them a little loose' than 'too tight'. He phoned me the next day when he'd stripped off the rocker cover to confirm two exhaust valves were 'slightly loose' but he didn't think it was worth doing them as then they would be 'a little tight'. He asked me if I was happy to go with his decision which I was.
In the end I trusted this guys opinion. He had just sold his E46 M3 and he seemed to know what he was talking about. Very impressed with Batemans, price and customer care. I've posted on the dealer feedback site if you want to read more.
.
He said he thought it sounded fine and that a little tappety was good in his opinion. 'Rather have them a little loose' than 'too tight'. He phoned me the next day when he'd stripped off the rocker cover to confirm two exhaust valves were 'slightly loose' but he didn't think it was worth doing them as then they would be 'a little tight'. He asked me if I was happy to go with his decision which I was.
In the end I trusted this guys opinion. He had just sold his E46 M3 and he seemed to know what he was talking about. Very impressed with Batemans, price and customer care. I've posted on the dealer feedback site if you want to read more.
.Gorbash12346
Member
problem is some dealerships i.e. my old one would tell you to just change the rocker cover gasket... i refused to take the shortcut and got a bollocking for taking too long, my current dealership does ask for the cars to be left overnight however and it gets done properly (though admittedly some people moan about the car being so quiet that it doesn't really need it.
it's not too bad a job to be honest and it's easier on the z4 than on the M3 but the actual changing the shims etc is a bit fiddly and tbh to get it just right it's quite time consuming
if someone pays for something to be done to their car then they should have it done and done properly as i've been on the recieving end of this kind of stuff too
it's not too bad a job to be honest and it's easier on the z4 than on the M3 but the actual changing the shims etc is a bit fiddly and tbh to get it just right it's quite time consuming
if someone pays for something to be done to their car then they should have it done and done properly as i've been on the recieving end of this kind of stuff too
flimper said:
You want to be careful with Sunningdale - always ask them to check with the technicians and tell them the facts you know.
Ive had to do this on various things....
You know its needs to go in overnight - so tell them that - dont be allowed to be fobbed off!!!