Scheduled Maint. Question

[lwebb]

My RX300 has 26,000 mi. on it. I have been following the normal use schedule for my scheduled maint. and using a local lube shop for the service. When I look in my owners manual, I don't see anything that needs to be done on the 30K that my local lube shop can't do. I have never had the transmission serviced. The manual hasn't call for that. Is that something I should have done?

[RX in NC]

If you'll spend some time looking at the posts on this site which discuss the common negative experiences of RX owners and their transmissions, you'll begin to understand that the automatic transmission is the biggest weakness in the RX line-up. Take it from those of us who've been there.

Play it smart and change your transmission fluid every 30,000 miles regardless of what your Owners Manual says. Always use Toyota Type T-IV automatic transmission fluid - allow NO other fluid type to enter your transmission case. You can change your own fluid - it's very easy to do. You'll need a 10 millimeter Allen wrench to unscrew the drain plug, and you'll need 4 quarts of Toyota Type T-IV fluid from your local Toyota parts department (they sell it cheaper than Lexus does). Drain your fluid, and start by filling 3 of the 4 fresh quarts through the dipstick tube using a small funnel. Keep checking your dipstick level as you slowly add fluid from the 4th quart, and by the time you're done you will have used almost 4 quarts of fresh fluid. Be sure to continue to check your fluid level as you drive the vehicle over the next 24 hours to ensure that you've got it right.

Changing your automatic transmission fluid every 30,000 miles is a small price to pay to minimize the likelihood of transmission failure. These RX transmissions are prone to wear out prematurely if the fluid is not changed regularly, and you should bear in mind that Lexus wants about $7,000 for a new (rebuilt) one....

[lwebb]

Thanks for the good info. I'll be sure and change the transmission fluid. I do check the level with the vehicle running, right?

Is there any other service issues I should know about?

[RX in NC]

A couple of other common RX failures involve the exhaust manifold and the multiple oxygen sensors on this vehicle.

The exhaust manifold has a tendency to crack so have it checked for leaks. If you find that yours is indeed cracked, it is a warranty issue and your Lexus dealer will replace it at no charge.

The multiple oxygen sensors tend to begin failing early, sometimes at less than 50,000 miles. You'll see a "check engine" light illuminate on your dashboard, and your best bet at that point is to go to your nearest AutoZone where they will plug in their code reader and determine your trouble code at no charge to you. The trouble code can then be cross-checked to inform you what's wrong. It's usually one of the sensors. Lexus charges extreme amounts of money for these little devices, but you can usually save yourself quite a bit by going to www.oxygensensors.com and ordering them yourself.

Good luck with your RX. This site has provided me with numerous RX maintenance tips and tricks over the past year. That has enabled me to save significant money in maintaining my wife's RX myself. She likes the vehicle but I don't and since I'm the one who must work on it, we won't be buying another one after she wears this one out. Just too many flaws and they're overpriced and underpowered.

[APN]

A couple of other common RX failures involve the exhaust manifold and the multiple oxygen sensors on this vehicle.

The exhaust manifold has a tendency to crack so have it checked for leaks.  If you find that yours is indeed cracked, it is a warranty issue and your Lexus dealer will replace it at no charge.

The multiple oxygen sensors tend to begin failing early, sometimes at less than 50,000 miles.  You'll see a "check engine" light illuminate on your dashboard, and your best bet at that point is to go to your nearest AutoZone where they will plug in their code reader and determine your trouble code at no charge to you.  The trouble code can then be cross-checked to inform you what's wrong.  It's usually one of the sensors.  Lexus charges extreme amounts of money for these little devices, but you can usually save yourself quite a bit by going to www.oxygensensors.com and ordering them yourself.

Good luck with your RX.  This site has provided me with numerous RX maintenance tips and tricks over the past year.  That has enabled me to save significant money in maintaining my wife's RX myself.  She likes the vehicle but I don't and since I'm the one who must work on it, we won't be buying another one after she wears this one out.  Just too many flaws and they're overpriced and underpowered.

RX in NC

You are very knowledgable on this RX300 subject. I had the CEL on my wife's 99 RX300 (84k miles), Autozone read code P0171 (System too lean Bank 1), other discussion pointed me to the Air Fuel ratio sensor. I learned that bank 1 sensor is the one closer to the firewall. I could loosen the mine, fearing breakage I brought it to the local shop (Honest Engine) to have them remove it. They didn't do anyhting special other than forced it out, part of the thread came with the sensor and they made me pay for it claiming that Lexus must have crossed treaded putting it in. So I was out over $1100 for the manifold, gasket, sensor and labor. AND now I still have the same error. Unbelievable !

Can you please tell me which sensor the dealer replaced on your wife's car ? Bank 1 (near firewall) or bank 2 (near radiator). I will never to back to Honest Engine again and cannot afford to feed the dealer at this point. Did you ever clean the Mass Air Flow sensor ? How did you do that ?

(I will not buy another RX either)

Thanks

APN

[RX in NC]

APN,

The dealer replaced our Bank 1 Sensor (the one near the firewall) in August using their "goodwill" warranty extension. This sensor failed at about 68,000 miles. Both trouble codes pointed to this particular sensor, and its replacement fixed this particular problem on my wife's RX.

No, I never cleaned the Mass Air Flow Sensor because the trouble codes did not point to it. Plus, our Mass Air Flow Sensor failed last October and was replaced by the dealer under regular warranty at about 48,000 miles. Damn these multiple lousy sensor components - I've never had an oxygen sensor fail at less than 120,000 miles on any of my other vehicles, and we've had at least a dozen different vehicles (none of them either Lexus or Toyota) since oxygen sensors first came into widespread usage on vehicles in the mid-1980s.

Other RX owners on this forum have described how they cleaned their Mass Air Flow Sensors as part of their troubleshooting process. It typically involves using a can of throttle body cleaner spray as well as a can of compressed air. Check the forum threads from this past July and August and you'll see some excellent details of just how several folks went about doing this. In a couple of cases, cleaning this sensor fixed that individual's particular problem. But you have to take your time, use the cleaning products carefully, and be sure not to oversaturate the sensor components with the cleaner fluid. The canned air assists in creating rapid evaporation of the cleaner fluid so oversaturation is avoided.

Keep in mind that if your particular trouble codes don't point to the Mass Air Flow Sensor, you're probably not going to succeed in turning off your "Check Engine" light on your dashboard by cleaning it.

[APN]

APN,

The dealer replaced our Bank 1 Sensor (the one near the firewall) in August using their "goodwill" warranty extension. This sensor failed at about 68,000 miles. Both trouble codes pointed to this particular sensor, and its replacement fixed this particular problem on my wife's RX.

No, I never cleaned the Mass Air Flow Sensor because the trouble codes did not point to it. Plus, our Mass Air Flow Sensor failed last October and was replaced by the dealer under regular warranty at about 48,000 miles. Damn these multiple lousy sensor components - I've never had an oxygen sensor fail at less than 120,000 miles on any of my other vehicles, and we've had at least a dozen different vehicles (none of them either Lexus or Toyota) since oxygen sensors first came into widespread usage on vehicles in the mid-1980s.

Other RX owners on this forum have described how they cleaned their Mass Air Flow Sensors as part of their troubleshooting process. It typically involves using a can of throttle body cleaner spray as well as a can of compressed air. Check the forum threads from this past July and August and you'll see some excellent details of just how several folks went about doing this. In a couple of cases, cleaning this sensor fixed that individual's particular problem. But you have to take your time, use the cleaning products carefully, and be sure not to oversaturate the sensor components with the cleaner fluid. The canned air assists in creating rapid evaporation of the cleaner fluid so oversaturation is avoided.

Keep in mind that if your particular trouble codes don't point to the Mass Air Flow Sensor, you're probably not going to succeed in turning off your "Check Engine" light on your dashboard by cleaning it.

Thank you for your time. I will do that and report back to everyone.