johnatg

Yes - in a word! You can use any wheels with the correct offset (and that doesn't matter too much, within limits), correct PCD of the bolt holes (that does matter!) and correct centre bore (and bigger ones can be reduced with adapters). Any wheel originally used on any IS will be OK. But you must choose tyres which give you more or less the same circumference as the originals - there are various tyre size calculators online to help you do that. Your tyre pressure guide on the door jamb probably lists the correct tyre sizes for different diameter wheels. Certainly the handbook does.

I don't think it's very likely that the aircon pipes have anything to do with it - they don't get any significant condensation. There is a drain from the evaporator, but that shouldn't discharge at all onto the transmission unless it's been damaged or misrouted. I think I might spray a dose of waxoyl over the electrical units on the side of my transmission when I get the chance - it does a good job of protection against damp and in particular the salt in road spray. Do you live by the sea or somewhere that uses huge amounts of salt over long periods of the winter?

Anything is diy if you've got the skills, facilities and test equipment. I think the main problems here will be access - the electrical switches etc for the transmission are situated on the nearside (rh drive cars) of the casing. The neutral switch is mounted high up near the front of the transmission. I suspect that getting to it and the wiring will be one hell of a job and it will be impossible unless you can raise the car safely to more or less head height (ie a lift is going to be all but essential). I think it's a good bet that fixing these issues will fix the gearchange problems you've experienced (but you might want to consider a bit of changing of the ATF as I mentioned before). Yes it's expensive - but I'm afraid that's the consequence of driving a particularly complicated car and despite usual near-perfect reliability, when something does go wrong it costs. On balance, I think that even I would go to a dealer for this. It might be false economy to compromise - but your decision. The car probably has 50K miles, maybe much more, left in it - consider its actual value now and its value to you. Or consider what someone else did recently when confronted with a major expensive problem - ask them how much they'd allow in p/x for it unfixed against a new or stock s/h car? If you're in a position to cope with that!

Hmm - that's all a bit worrying for the rest of us! Not surprised - diagnosis certainly fits the symptoms. It's a bit wally of them that they couldn't find it in the first place - this attitude of 'nothing wrong if there's no fault code' is typical of reliance on 'modern' technology instead of good old fashioned garage know-how. Main dealer labour charge of £100 per hour is pretty average - cheap even if you were in London (which I guess you can't be). I expect most of the loom could be saved, but that might take hours and hours - and anyway, main dealers don't fix faulty (or even dirty) items - just rip it out, chuck it away and fit a new assembly. And (almost) no Lexus parts are cheap. Not that I'm cynical of course......

Yes - but it needs batteries, and they'll be forever flat. I find one like this much better: http://www.ebay.co.uk/itm/PROOPS-METRIC-DIAL-CALIPER-VERNIER-MICROMETER-150mm-15CM-STAINLESS-HARDENED-/351211489820?pt=UK_Measuring_Tools_Levels&hash=item51c5d60a1c And yes - you just need a couple of small hard flat things either side of the disc. OK a micrometer would do the job in one go, but you'll probably only use it once in a blue moon, especially a 25-50mm one. Dial calipers are quite useful for quite a range of things. (eg you can use the depth function for measuring the brake pads!)

Those dimensions are correct. Discs don't wear much and they are more likely to be well grooved and generally not in great nick before they measure less than 25mm. They usually last over a couple of pad sets. Once upon a time they lasted more or less the lifetime of the car, but banning asbestos has meant that pads are much more abrasive now. You can get bigger mikes on eBay or from places like Machine Mart. But don't bother - buy a dial caliper instead. Hold a couple of nuts against the discs and measure the combined thickness with it, then deduct the combined thickness of the nuts. That avoids measuring the edge crud. Dial calipers measure to 0.1mm - all you need. You can get digital ones but they need batteries and if you don't use it much they'll be flat whenever you do want to use it. Mechanical ones are fine. Measure pads from friction face to the start of the backing plate - ie just the 'lining', as we used to call it!

You may note that Magnatec 5W-30 comes in various ACEA specs - commonly A1 (which is mainly Ford spec) and C3, which is mostly everything else. The C3 version was 'developed specifically for engines requiring Dexos2 spec oil' and is also approved by Mercedes, BMW, VW etc (some for long life, others for normal maintenance regimes). Well - forget extended maintenance regimes (for any car) unless you want get rid of your car after 3 years. Dexos2 (which is a specification as well as a specific GM product) is designed for dual use in petrol and diesel engines which means it has high detergency (keeps engine internals clean), and produces few particulates (it is designed not to clog DPFs - but that's also down to how the vehicle is used) But it is also recommended for all GM vehicles except in USA (there they recommend Dexos1 for petrol engines - not obtainable in Europe). I reckon that if it will do for everything from an Adam to a 'Vette Z06 it ain't gonna do our IS250s any harm! Not that I have any particular opinions about GM cars, but they do make a lot of them and one can expect their maintenance recommendations to have some validity. Why pay more? Much of the price of 'popular' oil is down to advertising budgets - especially where the advertising, in whatever form, is going to be seen on multi-million TV sets around the world on programs which 'petrolheads' might be expected to watch!

Just over 6 litres. (6.3 officially, I think) I always use GM Dexos2 (genuine GM, with the hologram on the label and the multi-language booklet on the back). It's 5W-30 fully synthetic. Available on eBay for about £20 for 5 litres and better value if you buy 2 or 4 cans at once. And I change every 5K miles with an engine flush additive and a new filter.

That's due to the torque converter - acts a bit like a slipping clutch on a manual gearbox. Really - nothing to worry about!

It's normal - you've changed down a gear!

S4026 - at least, that's what I have fitted (2006 IS250) - double check dimensions with your fitment. £62.34 delivered from CarParts4Less. (That was in Jan 2013)

It's gonna jerk if it's switched from D to N in motion!

All you can do is to carry on driving it but watch out for cold damp mornings (or some other triggering situation)! Maybe it was a one-off ocurrence - but it could easily reappear!

They are not sealed - there is a drain plug and you can change the fluid. But they hold 7.2 litres and you can only drain 1.0 (or 1.5) litres (info varies) at a time, so it would take a lot of drain/refills to change the majority of the fluid. Probably worth one or two drains at your mileage, but I'm sure it's not the basic problem.

Slipping symptoms - High stall speed. That's when a test is carried out by connecting intelligent tester, pressing hard on brake pedal and accelerating until the engine stalls. It should be ~2550 rpm. Do NOT try this at home! Re moving from N to D or N to R there should be a shock felt - the time lag should be less than 1.2 secs and 1.5 secs respectively. If it's longer, it indicates one or more of the clutches is worn (I think there are 3 or 4 clutches) I still think it sounds electrical - intermittent - dampness in a solenoid, drying out when it gets warm?

I think it's very unlikely to be a problem with fluid level - that can cause jerky shifting, but not like you describe. Sounds electrical to me - solenoids/relays or the transmission ecu.

Not sure what's involved - maybe you can just replace the motors rather than the actual headlights. Or maybe it's something much simpler - some sort of reset? The inspection routine in the workshop manual starts by connecting the Intelligent Tester and using it to drive the headlamps up and down. Followed by possible replacement of the 'AFS ecu'. Then there are whole series (several!) of resistance measurements on connectors and the motors. It looks as if the motors can be replaced. If you have HID headlights there are swivel motors too - removing them involves drilling into the headlight units (eek!)

Sounds as if your self-levelling function got stuffed by the shock from hitting the pothole. You should get it checked out - it might be very expensive to fix. Can you get evidence of an reported-but-unfixed pothole? - sometimes you can claim for pothole-induced damage from the council.

'Idle-up' is perfectly normal when running cold - it's because a richer fuel/air mixture is being burnt. All cars do it - otherwise there would be danger of stalling when any load is put on the engine - maybe you just haven't noticed before! (because the Lexus runs so quietly at normal idle and the rev counter is very accurate) It has nothing directly to do with raising engine temperature, but coolant temp is one of the vital parameters the ecu uses when computing fuel injection quantity. In the olden days, pulling our chokes out (ask your dad!) used to raise revs quite a bit! :eerrrmm:

Ever driven a 'supercar' in snow? - it's like trying to drive a snowboard! Wider tyres, less pressure per sqare inch = less grip in snow. In wet or dry conditions 225s on the rear are perfectly acceptable unless you're indulging in drag race starts - and probably even then most of the time. Rally cars use very narrow (think Morris Minor 1000 apparent width) tyres on deep snow stages. (But with studs usually - don't try that on British public roads!)

I've heard that they make serious deductions from the original valuation for every tiny fault - stone chips, leather creases, trim marks etc - and that's after you've laid out initial fees. Beware webuyanycar!

You can replace all the interior (overhead) bulbs with LEDs - kits available on eBay. That makes it much nicer. Don't think there is much you can do about the switchgear and instrument lighting, but I find it well adequate - in fact I usually turn it down quite a way out of town. Irritating that there appears to be no instrument light in the dimmer switch! (BTW - to replace overhead bulbs, get a set of plastic trim removal levers - avoids damage to plastic parts - easily marked with other tools and they are mostly very tight with tiny clearances to lever into)

I've been using TEC 2000 recently, but mainly because I came across a job lot at a good price. I'd be as happy with STP or Wynn's or more or less any other brand. I change oil with flush at 5K mile intervals - maybe a bit OTT, but it means I don't worry if I go over by 1000 miles or whatever. And I'm obsessive about a clean engine (inside!). An interesting anecdote from Saturday's Telegraph car section - Honest John questions. Someone wrote in to say they had their first service on a Mk 7 Golf 2.0TDI at 19000 miles and the fuel economy seemed to have improved. Response - 'You had the first service at 19000 miles? I hope you're not intending to keep the car for long' !

I always use an engine flush additive before each oil change. I used to have a Saab 900 and I flushed that at every oil change too, with no problems. Flush additive can cause problems if it is used in a very dirty engine, as it can loosen heavy deposits, large particles of which can block oilways. Some Saab engines, and for some reason particularly those fitted to the 9000 and 9/5, suffer from heavy silting - it is very common for the oil strainer on the pick up in the sump to become blocked and this can lead to engine seizure. I suspect that the best flush in the world can't dissolve the crud, and flushing just adds to the problem. Sad, but Saabs are disappearing very quickly indeed! They were a good left field choice, as is the Lexus.

That's true. However, pussyfooting around isn't necesarily the best policy. One of the problems that car manufacturers have is testing for the real world as their test vehicles inevitably get driven fairly hard during the relatively short test period before release. So problems relating to hard driving are found and fixed - but they often don't find problems which might arise with a car which is driven very softly - eg. two miles in the morning and two miles home in the evening, all at 30mph. For example., diesel cars are best suited to use for long motorway thrashes. Then combustion is pretty much complete for the great majority of the time and DPF regeneration gets plenty of opportunity. A diesel car which is used for short journeys, never gets properly warm or never driven at speed will clog its DPF in no time. I'm sure part of the DPF problem generally is that manufacturers didn't find it during development testing. Similarly with direct injection petrol engines (eg IS250). Reading the copious amount of information on this subject, it is clear that carbon build up on the inlet valves is related not only to fuel and oil, but also to how the car is driven. It is more likely if the car is not driven hard. I'm sure a lot of IS250s never get above 2500rpm, especially autos. Use those paddles, hit the red line every so often (or at least get into the orange) and maybe you will never see carbon build up occur! Won't do much for fuel economy, but might save a lot of money and grief over a car's lifetime!