lexusgal60

RX300 2001 160k miles. About a month ago, my CEL came on and I went to dealer who said I was low on oil. Oil changes are done as scheduled so ???. Then CEL light came on with a code about catalitic converter sensor bank one. Code was reset and has been burning oil. CEL light came on again with 0330 code knock sensors. I have been hearing engine knocking. I've read about starting with high octane gas or replace the wiring harness, etc...all of which are cheaper than replacing sensors.

Can any of these be related to the sudden burning of oil? I have a good mechanic but want to be prepared to discuss intelligently. Time to sell???

thanks

salimshah

Replacing knock sensor is easy but needs lots of hours (labor). @160k miles, it is probably needed.

Burning oil needs investigation ... compression test etc. Check for drips and leaks first. When oil is burnt, you also see thickening/dark oil (there are other reasons too). Do you drive at rpms greater than 3000?

In current condition, only a mechanical savvy person will buy and most likely offer you less.

Salim

lexusgal60

thanks. I would never sell it like it is, what I meant was after the repairs, thinking is this the beginning of the part where it starts having problems...

There are no drips or leaks of oil and when I check the oil, it is clean. I have noticed that it won't shift into overdrive all of the time and this may mean I've gone up over 3000 rpm...sorry, I'm a girl so I usually look at the other guage!! I'm just wondering if this is all somehow related. If the knock sensors are any of the cause of the knocking and/or not shifting into OD, is that any part of burning oil?

Someone said put a bottle of injection cleaner then use high octane gas....recommended?

Thanks again.

hypervish

Yes, the knock sensor will prevent the car from going into overdrive. Once you replace it, the RX will use overdrive (4th gear).

I highly doubt this is the beginning of where it starts to have problems, it's a toyota. This sensor is something that dies overtime, and it'll die easier/quicker if you use regular fuel. If 93 octane fuel was used the sensor may not have died.

salimshah

There are a few posts that talk about burning oil at high speeds (say 80mph + ... specially intercity .. longer distance). So I would suggest slow down and monitor loss of oil [that is if your mechanic does not do a compression test for you].

People sell vehicle "as is" as ethically there is noting wrong with it ... other than inviting low ballers ... and I will reserve my opinion on not disclosing the status.

I suspect you are thinking how long before you see the next problem? A question that is very hard to answer. Personally if you have low compression, you are approaching a need for engine overhaul. The money you put into fixing it up, may not be justifiable .. but that is just me.

As far as knock sensors, they have a life (and support harness). 160k miles is not bad while 90k is a bit premature. By using premium you can reduce the knock. Keep in mind the knock sensors do not sit inside the chamber (they do not get cleaned out by additives).

Salim

hypervish

My RX is mostly used on highway road trips to Michigan monthly, and I'm usually going about 85-95 mph to be honest...lol It doesn't burn any measurable amount of oil. But, my RX reaches redline every single time i drive it (once fully warmed up of course).

I think driving it hard once in a while is good for the engine, all Toyota's I've owned have been beat on hard, and none of them consumed oil except for the 89' van it started at about 250k, and it was only about half a quart every 2k, and the oil was changed every 3k.

Check your pcv valve, as that can cause oil loss at high speeds.

carguy07

Like he said above, check the PCV valve and hoses to hopefully track down the oil consumption. If it is consuming oil, it will likely knock since burning oil = detonation. Wondering if there is a chance that the sensors are fine and reporting excessive detonation due to the oil consumption?

hypervish

Even though it is a 2001, there could still be a chance of sludge just like any other car would if the oil changes weren't done on time, and/or if the car was abused...

lexusgal60

oil changes were done on time and car was not abused. mainly to work and soccer mom. no racecar driver wannabes.

autox250

unfortunately race car or soccer mom... the 3.0 - 3.3 family is a sludge builder. anywhere from the old ES's to the last of the 330's RXs & ES'. I had a similar case to yours on another RX300. You definetly have some extent of sludge, the consumption starts when the PCV gets clogged and on cruise it build up crank pressure and increases blowby. later on more of that starts to accumulate on the piston rings and then you have constant consumption at any driving range. That consumption WILL make the 300 ping and set off the knock sensors... enough abuse and the sensors will fail internally eventually. The wiring harness is a short 12" pigtail that has the connector for both sensors. What i've done in my case, I had bank 2 pinging.. I replaced both knock sensors, PCV, pigtail and performed the top engine clean that we do on the IS250s IS350s for rough idle concerns followed with vacuum fed BG solution thru the throttle body. Car runs great now

autox250

pictures after the RX300 clean up, 140K
1st pic, ports
2nd pic, lower manifold
3rd pic, upper manifold

lexusgal60

Wow! You lost me at PCV, but I'll share this with my mechanic. I'm trying to avoid the dealer repair costs and he's done a fantastic job so far. Just wondering if you think I should go to the dealer for repair or is this something a good mechanic should be able to do?

Lexmex

Amazing photos

autox250

the dealer wont go this in-depth, they'll quote you for a short block (the bottom half of your engine). I do work at the dealer, the short block only route is because they can 'warranty' the part or labor. I took it upon myself to offer the service writer another option other than a 20hr+job + parts (maybe 2-3k). Your mechanic can totally do it, infact have him change the PCV regardless.
If you'd like to share with him what I've used is, GM Top Engine Clean & BG Induction Cleaner. I ran them both through the throttlebody @ 2,000 - 3,000 RPM.
Maybe your knock sensors aren't bad yet & with the cleaning alone no more codes!

I'm doing it to my IS250 again when I hit 60,000.. its only 5k away.. now THAT has carbon buildup lol

salimshah

I needed to replace the knock sensors at 140k miles. The engine has no sludge issues. Based on other posts here, the knock sensors start going bad around 100k.

Salim