Hi all,

Have had the P38 now for a few months and now want to give her decent service, for which I have all the bits ready to go. I am wondering whether it would be wise to put a can of engine flush through before draining and then some additive during refill? Not being over familiar with the BMW engine, I don't want to upset it!
Secondly, with 127,000 on the clock, I am looking to also service the auto box. I brought the filter kit when buying the other filters but have been told it's not as straight forward as an engine service and as such am opting for the garage route. I have phoned around local garages, with the local L/R specialist quoting £120 stating that half the ATF stays in the torque converter and can't be drained, which seems like half a job - mixing new oil with old?? Another garage quoted £150 but stated that all the fluid would be changed as the torque converter can be drained. Confused and not wishing to be mugged off....could someone advise me please?

Many thanks
Rob

The first garage is correct....and so is the second!

A fluid drain from the gearbox sump will drain about 60-65% of the oil, the rest will be in the torque converter. And is no more difficult than an engine oil drain, except refilling is best done with either a long hose and a funnel, or a pressure sprayer type of thing...as the refill plug on the later vehicles and the diesels is on the side of the gearbox....not an esp. hard job just fiddly to fill.

The second garage are no doubt talking about a machine that will suck and flush all the fluid out of the gearbox including the torque convertor...often called a Megaflush.

Trouble with a megaflush is that ATF is a very good detergent, and replacing all the fluid at once can lead to 'new fluid syndrome' this is were the clean fluid strip cleans the box of all the dirt and debris that is harmlessly sitting in nooks and crannies in the box minding its own business....this sudden release of the dirt can either contaminate the interior if the box or clog the filter or both....

Whilst a megaflush is supposed to clean all this out during the flush, sometimes it can take a few hundred miles for the crud to loosen off and cause some issues like clogging the solenoid valves etc.

Not common but not a rarity either.

But, that said....only changing 60% of the fluid is better than not changing it, and if you really wanted to do a good job....do a couple of fluid changes...this way you are changing 60% at a time, so after 3 changes you Re approaching almost 100% clean oil whilst avoiding potential new fluid syndrome.

Thank you Saint.V8,

Definitely gives me a little food for thought on the matter regards to tackling the oil change myself and even if I do decide to send it into a garage, I'm a little more confident that I'm not be ripped off.

On the other matter......is engine flush a good idea?

Cheers
Rob

Personally, I wouldn't bother with the engine flush, just change the oil and filter with good quality oil, and do it again in a few hundred miles if you think it needed a clean out.