metaron

Hi folks

I know the recommended oil to use for an 2001 RX300 is a 5W/30 but would it do any harm using a synthetic 5W/40?

Someone just burned me on ebay and sent me 5W/40(lexus brand oil) instead of the 5W/30.

Regards

M

Lexmex

Welcome to the Club.

You won't bring any harm to your vehicle by using a 5W40. What you might notice is a slight drop of in your fuel economy since it is a bit of a heavier oil. Does it say anything on the back of the bottle as far as the brand name (likely ExxonMobil).

metaron

Cheers for the quick reply lexmex.

There's just "Toyota Motor europe" on the back with a european address.


BTW I'm in the UK.

Lexmex

OK.

When I lived in Mexico I used to run 15W50 Mobil 1 and later 5W50 Mobil 1. A lot to do with the fact that oils I would find widely available in the United States, weren't available down there. Eventually, I was able to use a Mobil 1 0W40 that was acceptable as long as I used some additives (that was due to the environment and also some of my nocturnal activities ).

You should have no problem running the 5W40. It should hold up a bit longer than the 5W30 due to the effects of oil shearing.

metaron

I've got the MOT in a couple of weeks as well would it affect the emmisions at all do you think?

Lexmex

That shouldn't affect it at all when you go in for your test. The 5W40 should be less prone to get around any potential leak you have by your pistons (if at all), since it is a larger molecule. I use to run a higher weight when I tested when I lived in Mexico City (we don't have the tests here in Florida) and I passed using a higher weight oil, a Mobil 1 0W40.

Generally, when there becomes an issue with oil and testing is when the oil becomes so degraded (from use) that it can do 1 or both of 2 things. One, as I described above, it gets sheared to the point that it is no longer a W40 and can go under a W30 and then seep around the pistons.

Number 2 is what is called the crankshaft ventilation system. That should oil vapor/moisture back into the combustion cycle (there are hoses coming out of both the front and back block) in order to do this. That is part of the vehicle's emissions system. If the oil is old or degraded, more of this vapor/moisture will 'contaminate' the system and the result will be seen in your emissions test.

That is why before you do emissions testing they often recommend you do an oil change.

I have actually done a test at a friend's garage back in Mexico City with a gas analysis test before and after an oil change, and the difference in the readings was approximately 15% better after changing out the oil, more or less.

One other thing to keep in mind, is that there is a Castrol oil that I recomend Castrol Syntec 0W30, that for all intensive purposes mimics a W40 weight oil. Yet we have many owners on here, many of which live in states with testing, particularly the stringent state of California, and they pass without issue.

metaron

Lexmex I want to change the auto gearbox oil as well, what oil would you recommend?

Are there any guides to changing the gearbox oil with pictures?

I've changed the auto gearbox oil in a Citroen C5 before all I done was remove air filter casing then removed tranny sump nut then measured what came out in a measuring jug and placed the exact amount back in, they have 9L of oil but you can only get 4.5L out of it unless you completely take apart the gearbox which I'm not prepared to do. Is an RX300 similar?

If there is no guide online I'll happilly take lots of photos of the process and I'll post them on this site as a how to.

Is there anything else that needs changing? BTW I've never had a 4WD?

salimshah

British English -> USA English
gearbox -> transmission

The search will unearth a lot of information for you ... there should a sticky.

Salim

Lexmex

As Salimshah mentioned there is a sticky, https://www.clublexus.com/forums/sho...d.php?t=220061

So by deduction from your statement above, I assume your RX300 is Front Wheel Drive?

metaron

I presume so.

Lexmex

Take a look underneath and see if it looks like this. If you see that driveshaft that is to the right of the exhaust underneath the vehicle, then you have AWD.