BMW 728, 1997. Any issues?

Only general observation is 7 series tend to get all the latest and therefore not fully sorted toys - you have to get a later 5 series to get the same toys with reasonable reliability.

So saying Autocar raved about their 728 when it was new.

Waterpumps and thermostats/housings can be dodgy on this engine so *stop* if you get any signs of overheating. The head can warp if you ignore it. Idler pulleys can fail too. None of this expensive to fix, though. If you can find out if they've been replaced and when so much the better.

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What to Watch Out For Build date from 2001 shown on engine compartment label on top of front nearside wheelarch.

Be very wary of M60 730i and 3,982cc 740i V8s (the engines that were dropped in 1996). Some unsold 'P' platers still had the old engines. 728i may also suffer bore liner degradation.

Check all electrics, computer (see 5-Series) and aircon system carefully.

Check for duff cats, condensation corroded rear silencers from chauffeured cars. Chauffeured cars also most likely to suffer premature bore wear due to long periods spent idling. Solved by replacement block with steel-lined bores. UK imports from March 1998 fitted with steel- or Alusil-lined bores, but grey imports from other markets may not be.

Automatic transmission specialists don't like the 5-speed autobox.

1998: new 7s built before Nov '94 recalled to fit new radiator cap (very few cars involved, because new 7 not launched until August 1994).

Failure of seals of rear tail lights lets water in which causes the contact between bulb holder and bulb to erode and contact to be lost. BMW replacements from a dealer are £280 a side, fitted. 1998-2000 rated average for problems and faults, poor for breakdowns in 2003 Which survey.

General Warning about Automatic Transmissions: Many BMWs have "sealed for life" automatic transmissions (this applies to all of the E38 series with the exception of the 730i and many 5 series and also current cars). Regardless of whether you have a full BMW service history, the dealer will never change the auto fluid. Many of these boxes are failing around the

120-150k mark - often well outside of warranty and to a cost of £3.5k plus VAT. A good independent or automatic transmission specialist can and will change the fluid for you (and any good BMW independents will recommend this anyway), but the job has to be done properly with the ATF at the right temperature. This is commonplace in the US and means the box should last the life of the car rather than being the cause of it being written off. General advice is ensure the fluid is flushed out every 60k or more preferably at each Inspection II.

Poor throttle response in a 728i may be due to faulty camshaft sensor.

Nikasil problems were caused by high sulphur fuel which hasn't been around for many a year. Unless it's a barn find any Nikasil engines still around should be fine as it means they were never run on this 'cheap' petrol.

Apart from the petrol issue Nikasil gives longer bore life than steel.

They don't seem to be a source of problems. Check out Ebay prices - they're not in demand.

Mine - AMC of Tooting don't. And they're one of the best independents around. My view is the jury's out on this. I've not seem details of an ATF analysis at high mileage that proves it needs changing. It's likely a US thing - many across there think all oil should be changed every 1000 miles. ;-)

It is of course impossible to do a fluid change in the ordinary way since so much is retained in the torque convertor. Some say to do it with the engine running and open a line to the fluid cooler - so the pump forces the fluid out while you fill with new. But with the cost of the correct ATF you're in for a very large bill.

Crank position sensors go too. But same on any make.

I found a good bet was to let the engine idle with the door wide open. If the end of the door seems to jump up and down then the idle is rough enough to consider the car as a walk away.

Also even if the engine is trouble free, it's a good bargaining point to get the price down.

I'd agree. the 5 speed boxes are not ones that the auto specialists seem to slate, most of them reckon with changes of fluid and the filter on the pan every 24k they will go for a long time. An electric drill operated pump makes chaning the ATF a doddle, but you only get about a third out each go.

Depends on the make of the box. If it's a green label box it's pricey - black labelled boxes use ordinary Dexron. I just open mine and drain the pan, drop the pan and swap the filter and clean the magnets in the sump pan (usually very little deposit on them)

Then refill with the appropriate volume of lost fluid. If you catch it all, then you know exactly how much has to go back. Check the level as per the handbook.

Think a '97 528 will have the 5HP19 with the lifetime fluid. Earlier 5 speeds ordinary Dexron.

Thanks for the ideas on things to look out for folks. The one I was looking at got sold before I got to look at it, but I'm keeping my eyes out.

Unless there is an affordable engine workshop for 528 engines, I think I'll give them a miss. I've just been browsing through eBay at 528's Of the 43 cars it's brought up I've found five with engines that are either completely blown or overheating and smoking.

AND the owners of the broken crs STILL want more than a grand. OK, so a subject change, see new thread.

Don't buy a broken one, that still leaves 38 non obviously knackered ones.

True, but thats a high percentage of that engine knackered, which doesn't make for confident motoring.

That's the ones that are for sale though, equally there's some good 535s still out there.

The 528 was the first of the all ally engines. And like many of the ilk doesn't take neglect kindly. But it's basically the same as the ones in current production.