High mileage RX450h owners: what kind of maintenance is required?
 

I recently acquired a 2010 RX450h with 197K KM (122k miles) on it. Full dealer service history, but it seems like the previous owner skipped the scheduled spark plug service @ 192K (which is probably one of the reasons why they traded it in).

Should I get the plugs replaced now or wait until ignition issues arise first? How long do the OE plugs last?

What about the water pump & serpentine belt? Should they be replaced at this mileage as well? AFAIK, there doesn't seem to be any leaks yet.

What other high mileage maintenance items are there?

Thanks in advance!

Recommended maintenance is based on failure rate analysis and convenient service intervals. No one can tell you when the plugs will fail and when they fail and depending on how they fail, how they impact the coil-pack.

My view is, once you go past the recommended interval you are on borrowed time and failure may happen at the most inopportune time. For long-life items, you also dont gain much. I expect you will change the plugs once [maybe twice] in your ownership time. Unlike other services that you may gain 7 out of 10 by stretching the interval.

I am all for following the manufacturers [not necessarily the dealers] recommendations. If you want to exceed, that is all unto you and open to discussion.

Salim

All we can say is follow the maintenance schedule. If you want to know if you can push something then have a good mechanic inspect and tell you about the specific condition of your vehicle. Even then, a good mechanic isn't a fortune teller.

With a high mileage vehicle without a known history of maintenance, these would be the maintenance things that I would personally get sorted:

1. Replace ATF fluid in the hybrid transmission, and rear differential (if equipped with AWD) - I'd only use Toyota WS genuine fluid. I called this out as the first item because the dealer doesn't touch the fluid at all, so it's probably the original fluid from when the vehicle left the factory.
2. Replace engine coolant and hybrid coolant - I'd only use Toyota Super Long Life coolant which is pink in colour. If the vehicle has been fully maintained, then check to see if this has been done - there's a possibility this might have been skipped by the owner during a major service interval.
3. Replace all 6 spark plugs and replace ignition coils on the rear 3 as well, and keep the old ones as spares in case the front coils fail.
4. Do a load test on the 12 volt AGM battery under the cargo floor, and if it fails, replace it. If it passes, I'd put it on a battery charger for 24 hours to top it up every 3 months, especially during the winter months. The dealer doesn't do such tests during a service, so the battery is usually a weak link that will let you down during the colder months.
5. Get brake fluid flushed if there is no evidence of this work carried out during dealer servicing.
6. Replace HVAC filter if it is dirty - another commonly forgotten/neglected service item.
7. Replace wiper blades
8. If tyres are not wearing evenly or vehicle is pulling to one side or steering wheel is not in the center position on a dead straight level road, get a wheel alignment.

That's about it, I think!

Thanks for the input guys. Fortunately, everything suggested so far has been done on schedule according to dealer records. I'll probably take out the front 3 spark plugs and check the gaps manually since it's the only way to be sure.

I have a 15 yr old Sienna with 240,000km I bought new way back. I also skipped the spark plug change for it too. The 3.3L engine still runs strong and smooth, although the rest of the van is fairly beaten up now with my daughter mostly driving it the last few years. If I ever need to use it, I have to take a garbage bag out to clear a zone that makes it comfortable enough for me to sit in it. Anyway, at this point, the cost of replacing spark plugs made from meteorites is almost what the van is worth, and I think it involves partially lifting the engine out of the bay. I'm more worried about what problems a major disturbance like that would cause vs just let it go and see what happens. I will face a similar decision with my RX in the near future, if I think it's worth the investment.

I have a similar experience. 2002 Camry V6 with 175k km had a leaking rear valve cover so I got the mechanic to do the spark plugs as well since it takes a lot of time to remove the manifold to access the rear bank. I analyzed the old plugs and there was no measurable wear on the tips, it could've done another 100K for sure.

The problem with anecdote is that it doesn't really apply to the RX450h because the old 1MZ/3MZ engines in the Camry, Sienna & RX300/330 are very easy on everything in the combustion chambers due to having such low compression ratios (10.5:1) & low air to fuel ratios (Rich running engines are cooler than lean engines).

By comparison, the 2GR-FXE in the RX450h has a 12.5:1 ratio running in atkinson cycle lean burn mode which increases combustion temps. On top of that, it's a hybrid so MG1 puts a high load on the engine at all times to boost thermal efficiency.

I did my plugs at 115k. It can be done by just removing the windshield cowl and wiper stuff to make room. Much faster and easier than taking the intake manifold off. There is a video on youtube where i got the idea to try this method.

Plugs were also cheap at the dealer.
As already mentioned, I recommend you do the plugs and CVT transmission and rear diff (if optioned) fluid change with Toyota ATF WS.
Other than that everything should be regular maintenance and easy to check and replace when necessary. (Filters, Tires, Brakes, etc)

How bad were the plugs on your RX450h @ 115k? Did you notice any mpg improvements afterwards?

Thanks for the input

[QUOTE=HKPolice;10200641RX450h has a 12.5:1 ratio running in atkinson[/QUOTE]

True, but the 12.5:1 ratio is only a physical ratio. Atkinson engines typically don't experience the high compression pressures found in regular high ratio engines in most every day driving because they limit the intake volume. That is the whole purpose of atkinson, less intake, but more physical room for the combustion process to squeeze out a little more energy for a given amount of fuel. The high physical ratio in atkinson engines is really just meant to be able to bring up the low intake volume to more reasonable compression pressures for ignition.

Just like a turbo charger artificially increases compression pressure for a given physical compression ratio, atkinson decreases compression pressure, you could call it an anti-turbo charger. This is why atkinson engines are more efficient, but greatly lack the torque of equivalent sized engines (and in steps the beefy electric motor to make up the torque).

Good to know. I have 143k miles on our vehicle with original plugs and fluid. I will endeavor these shortly. It is good know that the plugs can be done on the 450h without removing the intake.

Plugs looked decent for their age, I didn't notice any major improvements in mpg, if there were any it was negligible atleast to me.
The maintenance guide calls for plugs to be replaced at 120k, so another 5k probably wouldn't have hurt but it was more convenient to have mine done when I did.

According to the maintenance guide, it recommends spark plugs at 120k miles. The plugs themselves were actually pretty cheap from the dealer (at-least in the US), it's the labor that makes the dealer charge really expensive. It's actually not that hard and you can save a lot of money if you DIY. With plugs that last this long, there is always a risk that they seize into the block, that is something you definitely don't want which is why I like to make sure they get done.

I always leave them well past the recommended change before I change them myself. Never had a problem. I liked the confirmation that someone has done it without removing the intake.

:thumbup:
Hopefully you never have a problem, working at a mechanic shop for a couple of years, I've seen too many to know it's not worth running the risk of having to pull a cylinder head off to fix a seized spark plug that cost a few dollars just to get a few more thousand miles out of it.

It's not worth the risk to me, I prefer to change them early, but to each their own.