Mike_Mac

Sounds like a good plan - these engines definitely don’t like dirty oil! Ref carbon build up - so long as it’s being well serviced, I wouldn’t worry too much - all DI engines do it and my only suggestion would be to consider cleaning the carbon out every 60+ thousand miles or so. Plenty of places do walnut blasting, and there is a DIY option if you’re a bit masochistic too!

The DIY sprays, on their own, do very little IMO. You're talking about carbon that's been baked onto the intake and valves over hundreds of heat cycles and nothing's going to do the trick unless it's incredibly strong - and would probably not be good for the rest of the engine! Where they do assist, is when you're using them to aid manual cleaning, which is what I did above. Which is very time-consuming and still leaves remnants. It is cheaper, though, but unless price is the driving factor, I's go for walnut blasting!

As i'm sure all IS250 owners know, the DI nature of the 2.5 V6 engine means that some degree of carbon build up is inevitable. I've just replaced the engine in the IS250 project I have ongoing, from a 183K mile, neglected and pretty beat-up engine, to a 29K mile, excellent history and good condition engine. So, for those who're interested, below is the intake and valves from the 183K engine: Not too nice! And here are the intake runners and valves from the 29K engine: Not as much, the runners are pretty clean, but there's a fair buildup on the back of the valves already. This is what they looked like after a lot of manual cleaning: Not perfect, but a lot of the remaining gunk was quite loose and soft, so should clear even more once running. So! It looks like it's not a bad idea to get your intake off every so often and see if it's worth givign it a bit of a freshen up!! 😄 I would also recommend walnut blasting vs DIY unless you're a bit of a masochist!

As an example - here is a valve I took out of the shagged engine: Here is the intake port: Here is the new engine (before) - much cleaner runners, but still carbon on the valve itself): And here's the result of a bit of manual cleaning (not perfect, but still - a big improvement):

As Vlad has already said, the latest installment has dropped...

Unfortunately the engines already gone - but I do have a few of the valves as a memento and a fair few pictures, so will post them up ETA - Now that i'm back at home (was out walking) - to say the UK IS doesn't have a carbon build-up problem because of the UK's better fuel is like saying you won't get drunk if you only drink low alcohol lager - it just takes a bit longer... I can categorically say that the valves on my 183K engine were carboned up badly. More interestingly, the replacement engine, at 29K and with a good history, also had quite a lot of buildup already - nowhere near as bad, but I still had to clean it out before I put the manifold back on (next video). I have photos of the before and after and it's clear as day! Unfortunately, because a lot of this project was shot at night in poor weather I didn't capture as much as I'd have liked, bu hopefully quality will improve when I get back to the GS and another project I just picked up last week... 😄

If you're looking at eBay for those lower balljoint arms I'd be careful. I fitted one a while back and it din't last long at all - went back to Lexus OE and the quality was significantly better. Ref alignment specs - not sure exactly, but sounds about right. As saidm, though, alignment can be bang on when static, but if bushes are allowing movement under dynamic load then that'll go south rapidly.

Correct. If bushes etc aren’t visibly worn or have play in them it’s fine. Mine was like that initially, but sway bars, new shocks and swapping of key bushes did the trick (sway bars not essential, but they make a night and day improvement!).

It's been a long, long while (over a year!) but I've finally motivated myself to get back into this and document the work done... More to follow (in much quicker timelines!) Hope you enjoy it:

No, it’s not the ARB link - it’s the control arm bushes I’m talking about, which are in diagram 48-02, not that one you added there. See parts 48075 and 48076 on the picture I’ve attached for what I mean. The other arm I mentioned is 43330 and 43340

I’ve been doing a lot of digging on this recently and regardless of what your mechanic has said I would think about replacing your control arm bushes and the small link with two ball joints on it at the bottom of the front suspension. Mine looked ok too… but they were not! Ive replaced those, and a lot more besides, including some in the rear, and it’s made a significant improvement - a stiffer set of sway bars also made a huge difference too. Ultimately these cars are older now and rubber doesn’t last forever. Another thing to check is the subframe braces at the rear. Both them, and the small arm that connects them to the subframe can fail due to corrosion and will make the rear end unstable (albeit your mechanic should have spotted this so it’s unlikely in your case). Hope that helps!!

Glad to hear it’s been sorted! 😃

That’s bad news, but at least you’re getting it sorted and stopping the root cause!

I am neither pragmatic, nor sensible, but my 2p (having no direct experience of this issue, to be fair) is that the last two options are both valid, but depend on three things. First, whether it’s just your Torque converter that’s at fault - in which case, replace is the simplest option. Second, whether you can find a used ‘box that you can actually observe working before fitting, which is a big question mark. Third, the deciding factor of cost vs benefit. A used ‘box is cheaper but more risky, whereas with a new converter you have new parts, not used, and a warranty, so more cost, less risk. personally I like doing things once and minimize risk - so would personally go for a new converter. /2p😉

If you clear the codes, you also clear the ECU's check logs of the various sensors, Cat performance etc etc - it'll therefore take a few trips or a certain distance before all the checks have re-completed and the ECU will be able to spot and flag up an issue. From memory, the O2 sensor check cycle takes either two or three trips (and moved from closed loop) before it's complete; with Cats, I believe they have to have been up to temperature for while.

The person owning that would have had kittens if they'd seen the state of my IS250 (when I first got it...) 😄 What a (potential) waste, as said!

In the middle of changing the Front Discs/Pads. I say in the middle because the slider pins are solid (New pins, boots and seals ordered). THe effect of this was to have the inner pads permanently applied, resulting in this: On other news, it's back from getting a new engine fitted (turns over really smoothly and looks like the mileage of 29K is spot on!): And as I started to put it all back together I pulled the Spark Plugs: Spot on! Way better than what came out the other engine!

BTW - Does anyone know it you can swap all the HID bits of a HID headlight into a Halogen one? My LHS one has lots of broken tabs, which I could try plastic welding, but a reasonable used Halogen one is about the same cost as the welder, so it would make more sense, if feasible?

Not the best picture as, despite my best efforts, China couldn't sent me an endoscope with a side camera, despite two attempts (!) so I had to make do with a normal one: However, the prognosis is fairly clear... That is not the worst one, just the one I managed to get the clearest photo of. Just like the UK, I'm now in the middle of 'Plan B'! 😄 On better news, the Alloys and Tyres, broken Tie Rod, Interior and Rear Shade are done or nearly so (because priorities!). Just need to find time to edit and thread it all together, as work has been mental recently and will continue so next week too!

It's taken longer than I'd thought, but the first video tracking my latest (dubious) purchase is below: As I'm trying to do a lot of things in a Car Park at work, the quality will likely continue to be a bit iffy, but hopefully it'll still be entertaining! Currently, I'm still waiting for an endoscope with a side camera to arrive, so I can check the bores (the one I originally ordered is going back - because China!) so it'll be a while before I get stuck into the engine again. I'll tackle the more cosmetic stuff first, just to give more time for daylight to start to come back in the evenings, making any engine work a bit more comfortable. So, much more to come, whether it'll prove a wise purchase or not, I couldn't possibly say yet!

Agreed. Problem is I need to do the WP and HG to do that, by which time I’ve spent a lot in parts… Forgot to mention that the wet results were uniformly 40+ Psi higher.

Although it was sold as a non-runner, it turns out it did start and run (as Copart showed in their pictures). What they didn't notice was that the water pump was totally knackered and had shredded the Aux belt too and I don't know how long they or someone previously had run the engine like that. Fearing the worst, I got it started briefly to get it to set the error codes and then turned it off and did a compression check. Dry results (admittedly for a very cold engine) were around the minimum viable numbers (~140Psi), bar one cylinder which was at 80 Psi... So, the plan is to next do a leak-down test to pinpoint why there is low compression in that cylinder, then get an endoscope in to look for bore scoring (which can be an issue on these engines if the Piston Rings have become stuck from carbon buildup). If the bores look ok, it's be worth doing the Head Gasket (if that's what it is). If they're scored, I'll be stripping this engine and installing a good used one, as it's not recommended to re-bore or hone these engines. I'm not too concerned, as I always had a contingency that it may need an engine, and TBH, i'm tempted to do it regardless, but need to do a lot more digging first (Once i've managed to find an endoscope with a side camera!!).

Connection just chose that time to fail, or the unit popped? Sounds like it should be easy enough to fix - not sure how much that'd cost, though! On other news, my plan to look at the bores has been put back a few weeks, as the endoscope with a side camera I ordered (made of the finest Chinesium) has arrived conspicuously absent one! Couple that with the cordless angle-grinder whose batteries are so loose one of them doesn't even power the tool, and I'm having great fun! I wish the options weren't just 'stupid expensive' or 'shoddily cheap' nowadays - there's no 'decent home mechanic level' option anymore...

Is it returning any codes? Does it crank and not start, or is it just not even turning? What's it doing (or not?)

Sounds like Copart!! 😐 mine is similar in terms of more to do than first appears, and I’ll be digging into the engine over the next few weeks to determine if I just stick a good used one in there (long story). Costs are staying ok so far, though…