johnatg

You don't need to change the rear brake pads at 4.5mm. Standard rear pads start at 10.5mm and the minimum thickness spec is 1mm (but note that the MoT requires at least 1.5mm). So 4.5mm is about 2/3 worn - plenty of miles to go yet!.

Check the calipers for sticking - either the sliders, which need cleaning and greasing regularly or the caliper pistons.

Is the engine management light on? (It must not be on) Is the EGR valve operating correctly and not blocked? (It must be operating correctly) Is there at least 20 litres of fuel in the tank? (there must be at least this amount) The DPF will not regenerate if any of those are not correct. Does it actually need to regenerate at the moment? I suspect nothing will happen if it doesn't.

Have you got the engine running and up to temperature?

That's the one - I thought all SE-L had a touch screen! Learn something new every day! Sent from my PSP7551DUO using Tapatalk

What does the little sticker just above the driver's door catch loop in the door jamb say?

That sounds as if you have an SE rather than an SE-L. (As do I) I suspect that it would be a major operation to fit a touch screen - I guess you would need most of the centre console and wiring loom (from a scrapper?) Anyway, from reports on here about Lexus sat nav, it wouldn't be worth the bother. You get better sat nav performance from free apps on your phone (eg Maps.me).

Changing oil at 5K mile intervals or thereabouts is fine. Not worth the expense of doing it more often. Don't leave it for much more than a year and don't approach the Lexus interval of 10K miles - IMHO that's too long but is specified to keep apparent fleet service costs down - but would be OK if you don't care what happens after 7 years or 100K miles or so.

Back to 'is there any difference (between brands). I reckon that if you use any 5W-30 oil (or whatever is specified) and it is marked with approvals (ie meets the specs) issued by a number of motor manufacturers such as GM, BMW Mercedes, VW etc and you change the oil within the mileage limits specified by Lexus or whatever car you are servicing you will be fine. There may be some quality differences that might show up if you did a controlled back-to-back test and stripped the engine to measure wear after say 100000 miles or if you drained the particular oil and ran the engine until it seized, but those differences would be slight.. So in extreme circumstances there might be differences. In normal every day use changing oil frequently and more often than recommended by the manufacturer (the single most important thing to do to ensure engine longevity) will ensure that your engine will last for 200 or 300 K miles without problems - at least without problems associated with the oil. And paying more doesn't necessarily get you a better product - a lot of the cost of oil is in the advertising - I shudder to think what all those posters etc at F1 Grand Prix, football stadiums etc cost. I use Exol Optima LSG 5W-30 - comes in a 20 litre drum for £59.95. I use it in my IS250, MX-5 (which is supercharged and has ecu add-ons which enable it to rev to about 7.5K - way beyond the 6.5K normal rev limit - and it is 28 years old), Seat Mii, Peugeot 208, my lawnmower and any other 4 stroke engine I get asked to service. Probably I wouldn't use it in a Ford because they have some particular requirements that I won't go in to here.

Can't really offer any suggestions about the problem, but the Intelligent Tester is a bit of hand-held kit which is used for a whole lot of service procedures. It's not Techstream, and Techstream can;t be used for the things the Intelligent Tester can do. They come up for sale sometimes - they cost about £200. I have considered buying one, but you don't really need it for most diy service things. But Lexus do specify that you need it, for example, to bleed the brakes and change brake fluid - but I think I have done those things successfully without the tester.Maybe I haven't cleared fluid from some of the darkest recesses of the system or something. And there's a host of other procedures in the manual which start off by saying 'Connect the Intelligent Tester.....'. I think it puts the ecu etc into some sort of service mode to override some normal operations or open up access to things like voltages within the system. It is plugged in to DLC3 - that is the OBD11 port/connector.

That'll be silicone spray - rather different from silicon! 😉 https://www.zmescience.com/science/domestic-science/the-difference-between-silicon-and-silicone/

0W-20 is the ILSAC spec. It's specified for fuel consumption reasons. If you want to squeeze the ultimate fuel consumption figure from your car, you would use 0W-20 (less resistance to engine rotation). If you want to protect the engine, you would use 5W-30. The difference in fuel consumption between the two is probably in the order of tenths of an mpg. But that matters in the fuel consumption wars in the showroom. And there's no reason to use anything other than fully synthetic in an IS250 - or any other vehicle for that matter, IMHO. I use 5w-30 fully synthetic even in my lawnmower, for example. I don't understand the people who say you shouldn't use fully synthetic in various, usually older, vehicles. I have never found any disadvantage with using fully synthetic - sometimes people say it's too thin and causes oil leaks - but 'thinness' or 'thickness' is in the viscosity spec - ie the 5W-30 bit.

Here you go: https://www.lexusownersclub.co.uk/forum/topic/116346-spark-plug-replacement-again/ I was wrong in that guide about the original plugs being platinum - I think they are in fact Iridium but with an additional platinum pad on the centre electrode. The IKBH20TT ones are 'new technology' iridium TT spec - a more advanced design (they also include platinum). The claimed service life of TT plugs is 120K km (72K miles) https://www.denso-am.co.uk/products/automotive-aftermarket/spark-plug-glow-plug/spark-plugs/iridium-tt/

I wouldn't worry about problems in changing the plugs. Some fasteners are a bit inaccessible, but it's an easy job. There will be no issues in removing the plugs when you get to them (and you can get to 4 of them with minimum dismantling - it's the two under the airbox which need its fiddly removal). My plugs were in for 12 years and 66K miles. I noticed no change with the new plugs (which are Denso IKBH20TT - the current spec by Denso for IS250 plugs and much cheaper than the originally recommended FK20HBR11) The new ones have been in for about 8K miles now with no problems. You may or may not need new gaskets for the airbox - i bought them and because they were to hand used them, but it really wasn't necessary to replace them but it might be different at higher mileage. I wrote a guide to the job - I think the thread is called 'Spark Plug replacement again' - about a year ago. Toyota branded plugs are Denso FK20HBR11

Hmm... I'd suggest you try and make some space and get Torque. Mine just works!

You need ignition on and obviously Bluetooth active on your phone. Are you using a suitable app? I've found Torque to be the best.

Switch the aircon on! Why do you ever have it switched off? Keep it on all the time.

It might be something simple - try replacing the cooling system pressure cap with a new one. But if that doesn't work: If there are no external signs of leaks from the engine (eg pink deposits) I'm afraid that the head gasket is the likely suspect. You won't necessarily notice anything yet - the leak could be quite slight between a water channel and a combustion chamber - that can even help combustion. But that's all temporary - sooner or later it will (probably) blow big time. You could get a cooling system pressure test done - even that may not show anything.

No doubt the sites where you saw that people had it done were US ones. For some reason it seems more prevalent there - no-one seems to know why - maybe fuel, maybe oil, maybe engine settings??? I don't think there has ever been a report on here of actual proof of carbon build up on an IS250 engine in UK. As others have said above, don't get it done unless you experience problems. Incidentally there is an article in this month's Car Mechanics about GDI engines (like ours). Carbon build up is obviously a problem even in UK for some GDI engines (Non-Lexus - lots of makes have GDI engines these days). The clean up cure usually recommended is walnut shell blasting. There is also a comprehensive feature in CM about EGR valves - all you wanted to know! (Heads up diesel drivers!)

I have seen this crystalline effect - and if it develops further it gets to look almost as if there's a brownish web of intertwined material growing inside the lights. But it's all on the surface. Use a metal polish (metal polish which is slightly abrasive, not car polish), rub hard by hand with a cloth or paper towel and it will all go - it needs some serious elbow grease. (I use a liquid metal polish which I bought in Sardinia to rub out scratch marks on paintwork from bushes on a hire car - it worked!). Afterwards use wax polish or wax coating (I use Meguiars three stage wax) and keep an eye on the lenses - you will need to repeat every 6 months or so.

It depends - probably a bit steep for paint, or was he talking powder coat? I was faced with the decision late last year. I went for new aftermarket wheels - about £1200 with Continental PremiumContact 6 tyres (17"). But if you get the wheels refurbed get them powder coated. I had mine painted (with paint) about 5 years ago and regretted it! They just blistered again within 18 months But I bought some well shot alloy wheels for my MX-5 about 3 years ago. I had them powder coated and they still look like the day they came back from refurb (but it doesn't get used in the winter) Sent from my PSP7551DUO using Tapatalk

Yep - min front brake disc thickness is 25mm in workshop manual- not sure what is etched into the rim of the disc but the minimum is always specced there as well. My car has solid rear discs - original thickness is 8mm, minimum 6.5mm. According to Lexus minimum pad thickness is 1mm, but the MoT spec is 2mm and you will get an Mot fail for less than 2mm. 2mm is somewaht lower than where the slot ends, so the slot can (usually) be completely gone before the pads are illegal

I'm afraid I agree with Jack. Almost certainly the head gasket has failed. The fact that the coolant is just water rather shows that this has been the case for some time. It is catastrophic to run a car with plain water coolant - a rusted rad is the least of the worries - it will corrode the engine internals in no time. 'Antifreeze' is not just there for stopping the coolant freezing - it plays a vital role in preventing corrosion in the engine

Well - Lexus - IS-F. OK it's a 5 litre V8. What's the point of trying to mod a 250 - you'd need to update the entire drive train, brakes, suspension, etc. A whole lot easier and better to just trade in the 250 for an F. Sent from my PSP7551DUO using Tapatalk

Did you know: 1) Run flat tyres can be driven on when punctured - but only for about 50 miles max at 30 mph - limits vary with brand but that's typical. 2) Most tyre places follow the puncture repair code of practice - which says that run flat tyres cannot be repaired. (Because running them in excess of the limits above may have damaged the structure, but the potential damage isn't visible) 😦