Newbie Gen3 RX450h owner questions

[Stevo11]

Hi,

I've recently bought a 2010 RX450h, I'm hoping someone could help with a few questions I have...

1) Is Premium petrol worth it with this engine? If so, how?

2) What is the better diagnostics reader to have? I have tried both the cheap and cheerful elm327 + torque app and my Delphi readers, just basic and real-time data available but no system testing with these.

3) This is sort of related to 2) as I want to diagnose the issue. My Dynamic Radar Cruise Control is not functioning, if I am stopped and press the button to start, I can select distance etc but as soon as I release the brake I get the warning triangle and the "not available" message. Is this common? Is there a fix?

4) I'm curious, what is the "T handle on a string" beside the rear seat side bolster for? It has "refer to manual" written on it but I'm not finding any reference 🙂

Thanks!

[Cypry 1]

The first thing that I would do is take out the Lexus 10 year plus extended warranty which is about £550 for a year which is payable by interest free direct debit.

You will be able to do it until 2025  hopefully.

[Stevo11]

Thanks, I'm not sure that's an option in Ireland, I'll check it out.

Also, I've another question 🙂

...

5) Are the top hats on the air suspension struts interchangeable side to side? I've had my passenger side top hat out and it looks like its been repaired with a new bearing so I'd like to "test" to see if its the cause of a knocking noise I have.

[Spottedlaurel]

In answer to a couple of questions:

1) I don't bother. My 2014 gen 3 is getting around 36mpg at present. I've tried premium, my driving isn't similar enough from one tank to the next to see if it makes enough difference to justify the cost, and it runs just as well wherever I get it from (branded or supermarket).

4) Possibly manual release for the tailgate or fuel filler flap? Too dark and cold to venture outside and checkmine at the moment....

[brendangeorge]

I can get about 30mpg in my 2012 model - I get a few mpg more from premium and I think the car runs better.  I am about to start driving more than 500 miles per week so will do some analysis.

The emergency filler door release is under the boot floor - this may help.

 

The emergency tailgate release is at the bottom of the back door - you have to crawl in.  See my post about my recent failure - there are many others.

I have attached a useful document for people who are new to the RX450h - it is the electrical system dismatling guide.  However, it has some really useful info in it.

Regards

Bren

 

RX450_GYL2.pdf

[Stevo11]

Aha, think I've solved 4), this is it

 

From the online manual :

[Stevo11]

Re 1) I guess I'm curious enough to try a tank 🙂 I see the "Best" in the "Past record" screen is 36.7mpg, I've been through a couple of tanks of very mixed driving, 31mpg currently. I'd expect that to climb when temperatures improve tho.

[Illogan]

On 1/27/2024 at 7:58 PM, Stevo11 said:

Re 1) I guess I'm curious enough to try a tank 🙂 I see the "Best" in the "Past record" screen is 36.7mpg, I've been through a couple of tanks of very mixed driving, 31mpg currently. I'd expect that to climb when temperatures improve tho.

My experience is that whilst I only get about a 5% improvement in mpg using premium fuel, (or, now, E10 with a fuel additive), I feel more comfortable hoping that the claimed additive ingredients counter some of the possible adverse effects of E10. And I've convinced myself that the engine is smoother, - (it isn't of course, but I'd like to think so!)

Most importantly,  - my mpg has improved over the few years I've had the RX, not because of magic, but I've learned how to drive it more efficiently in different road/traffic conditions. It helps that I'm never in a scalding rush to get anywhere!

[brendangeorge]

23 hours ago, Illogan said:

My experience is that whilst I only get about a 5% improvement in mpg using premium fuel, (or, now, E10 with a fuel additive), I feel more comfortable hoping that the claimed additive ingredients counter some of the possible adverse effects of E10. And I've convinced myself that the engine is smoother, - (it isn't of course, but I'd like to think so!)

Most importantly,  - my mpg has improved over the few years I've had the RX, not because of magic, but I've learned how to drive it more efficiently in different road/traffic conditions. It helps that I'm never in a scalding rush to get anywhere!

Hi Dave

I drove over 350 miles in the last two days.  The first half of the trip was using E10.  I have been struggling to get much more than 25 mpg lately but I have not been driving much.  With sensible driving I used to achieve 30 ish.

Last night I filled up with E5 and within 70 miles I was getting 28mpg with mixed driving: motorway, town, traffic jams etc.  I think the car runs smoother on E5.

I don't think I am suffering from confirmation or inclination bias - I test things for a living.

I am with you on the driving style - fuel economy and penalty points sorted mine out.

[Mr Vlad]

Hi Steve. The Only diagnostic tool you want is Techstream. It's 2nd only to what Toyota/Lexus use in their workshops. 

From memory when I had the F sport RX450H I never got below 35mpg. I only used E5 and always Millers Petrol Ecomax additive. My driving, as always lol, was with pace. Once when I drove like Miss Daisy I got 48mpg on a run from Rochdale to Leeds. I miss that car 😞

[brendangeorge]

That's impressive fuel economy Vlad.
I have a 2012 and 30 is doing OK.

[Mr Vlad]

It's the additive that adds a few more Ron to the petrol. Makes for a better burn. I recommend it to all petrol and diesel car users. I've been using it for decades and swear by it.

My car was a 62 plate by the way.

[JeffL]

26 minutes ago, Mr Vlad said:

It's the additive that adds a few more Ron to the petrol. Makes for a better burn. I recommend it to all petrol and diesel car users. I've been using it for decades and swear by it.

My car was a 62 plate by the way.

Which additive do you use?

[Mr Vlad]

Millers petrol Power Ecomax 

[brendangeorge]

I'll give it a go - I love magic potions.

Cheers

Bren

[Bluemarlin]

On 1/27/2024 at 7:58 PM, Stevo11 said:

Re 1) I guess I'm curious enough to try a tank 🙂 I see the "Best" in the "Past record" screen is 36.7mpg, I've been through a couple of tanks of very mixed driving, 31mpg currently. I'd expect that to climb when temperatures improve tho.

In my experience I get 3-5 mpg more with premium. That said, not all premium is the same. Esso used to be the best for mpg before they stopped zero ethanol, now Shell seems to be marginally better. Typically on mixed driving I get around 30/32 on premium and 27/29 on regular.

That said, driving style makes a lot difference, especially on long motorway runs. I find 60-65mph to be the sweet spot, and on a run over to France got an average of 40 mpg at that kind of speed. Funnily enough it rarely makes any difference to journey time, as the slower speed is mitigated by less slowing down for other drivers and then speeding up again, whih of course burns more fuel when accelerating. At 60-65 I find that sometimes I can maintain a constant speed for most of the journey with hardly ever having to touch the brakes.

[Stevo11]

My most recent tank (not premium) was 412 miles (53lt), just over 35mpg. Happy enough with that, it was 80% backroads too.

I have an 11hr round trip coming up but pulling a canopy trailer, I suspect I'll be in the 20's 🙂

[Stevo11]

29mpg, 270+ miles with a canopy trailer, not bad.

In other news, I replaced my NSF shock (air suspension) yesterday lunchtime, back to it's magic carpet ride 🙂

Next issue to sort out is the cruise control, I'm suspecting the front badge isn't the original...