Terraclean

[is200 Newbie]

A topic that has been raised before ... anyone had any recent experience with this being done to their Lexus?

[ChumpusRex]

I've been tempted to get it done myself, but it's very expensive, and I've not yet read a convincing testimonial (i.e. a car that failed on emissions, despite a thorough italian tuneup, but then passes after a teraclean). All the testimonials aren't particularly convincing, i.e. emissions fails on a barely warmed up engine, that is used as a city run-around, but gets better after a teraclean (no surprise as a teraclean involves running the engine hot for 1 hour).

I can't even comprehend how this is supposed to do anything. The big problem with the IS250 is the carbon build-up on the intake valves, and there is no fuel based cleaner that can touch that.

If you want to know more about the details of the procedure, here's the patent which gives a detailed description (which in my view is utterly nonsensical).

http://www.google.com/patents/US7674341

The problem with the intake carbon build-up is that short of blasting it off with walnut shells, there isn't a lot you can do about it. Even the big fuel additive companies have essentially admitted defeat.

http://www.oilem.com/turbo-fuel-stratified-injection-tfsi-direct-port-injection-carbon-build-up-problem/

[is200 Newbie]

Two good reads - explains a lot

Looks like there could be a lot of issues in the future over this?

[ChumpusRex]

The carbon build-up on the intake valves is a common problem on direct injection petrol cars.

On the US forums, the IS250 has horrendous problems with this, with many people getting engine replacements. It doesn't seem to be as big a problem in this country, possibly because the IS250 is less common, but possibly because the fuel quality in the US is terrible, whereas the minimum standard for petrol in the UK is extremely high.

It's also possible it is something to do with oil - in the UK, lexus specify 10k mile oil changes and most dealers use a high-end synthetic oil, whereas in the US lexus specify a 5k mile oil change interval, and in order to keep service costs down, lexus sell a special US-edition downgraded oil filter, and most garages end up putting the cheapest possible oil in.

Intake valve deposits are something which is now a specification for new oils - so the oil has something to do with it, and the latest specifications e.g. API SN do require the oil to be resistant to deposit formation. So, I try and use a fully synth SN grade oil where possible (I use the cheap Euro car parts Triple QX 5W30 C2).

[is200 Newbie]

I am monitoring my oil at the moment - not because there's a problem, its just something that I thought I would monitor to see what's going on with colour and levels etc.

I have read up a bit on oil - (not to the depth that you have) but now understand that the oil changes colour as it catches all the gunk in the engine as its designed to do. Basically, you can argue the blacker the oil the better to a point but monitor it for when it becomes saturated and then change.

I can see where the oil can have an effect as at the rate it does turn black in some circumstances may be within a few months use - from my initial change it has changed colour but not to a point where it needs changing but I can see it turning black before the recommended service interval is due. 2 months has seen a change in colour from being practically invisible on the stick to having a slight darkened tint but still transparent.

Its possible that the oil is actually carrying away the carbon built up in small amounts - hence it turning colour. I had a few instances of the carbon build up "shiver" experience the cars give out that are effected but that was last year and after a few doses of the BG44 and two oil changes it has not happened so far this year. I have also been using Shell with the odd occasion at Texaco and Sainsburys.