johnatg

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) 😦

You need Techstream (runs on a laptop). Available for purchase on popular auction sites.

Indeed. Why are you thinking of buying a diesel? The type of toys fitted will be the least of your problems. And stay away from Halfrauds!

Not a lot of response! But it's hard to tell from here. Might well be connected - but might not. Check all the usual things - fuelling in particular - possibility of an air leak in the fuel supply? One or more fauly injectors? Blocked fuel filter? Or a very blocked dpf - but that's not likely if it was more or less OK except for cold running before. Or off-the-wall unlikely things such as timing chain or crank position sensor?

Your car does have an EGR valve and it probably needs cleaning! Sent from my PSP7551DUO using Tapatalk

Yep - sounds like a dpf problem - possibly needs some good blasts to regenerate. You need to do at least something like 20 miles a day on deristricted roads (by limits or traffic) or 50 miles once a week if you drive any modern diesel with a dpf. Sent from my PSP7551DUO using Tapatalk

PS - whether or not it's the correct diagnosis is of course another matter altogether.

IS220D models do have an air fuel ratio sensor - see attached pic. Not sure if it's actually an oxygen sensor as used in petrol models but it is clearly what the first guy meant. From the workshop manual it looks as though you have to remove the front seat together with loads of trim and access the sensor via a hatch in the floor. Don't know if there are easier ways.

I use Comma Engine flush - you can buy a box of 6 on eBay for £15.84 on a current listing. Seems to work well. I don't think there's much to choose between any of the readily available brands of engine flush.

Indeed - I had a rear lining detach like that on a Pug 205 of my wife's years ago - ended up destroying the brake hub in getting it off. So yes - I do agree, they need checking and possibly replacing even on cars where the rear shoes only operate as a parking brake.

The front calipers only have one piston - they slide (and seize) just like the rears. But the slide pins are effectively bolts and have hexagons, so you can release them with a suitable spanner and if necessary a bit of wellie. Also they are less likely to seize than the rears as they do more work so keep moving more. Rear shoes shouldn't wear at all - they only wear if you drive off with the parking brake applied. You never do that, do you? 😉