Hey guys, quick question. I'm going to do the first oil change on my RX300. My first oil change was done at the dealer and cost me $60, so I'm doing it myself this time. I was planning on using 5W-30 oil instead of synthetic. Is this ok? How can I tell if synthetic is already in the vehicle? If there is synthetic in there now, will it matter if I switch to regular 5W-30?

Thanks

Lex Luther

 

Welcome to Clublexus. Yes, you can switch oils with no issues, they can mix. How can you tell? I honestly have no idea how to tell if its synthetic.

 

FAQ on Lexus's Website: Use of Synthetic Engine Oil

Question:Can I use synthetic engine oil in my Lexus vehicle during its break-in period?

Corporate Lexus's Answer:* "Synthetic oil can be used at the first scheduled oil change. Please note that the use of synthetic oil does not extend the recommended oil change intervals. Please refer to the Lexus Owner's Manual Supplement for further information regarding the proper maintenance schedule for your specific vehicle. If synthetic oil is used after that time, it should be the same SAE (Society of Automotive Engineers) weight specification and meet or exceed the API (American Petroleum Institute) grade specifications listed in the Owner's Manual. Even if synthetic oil is used, we do not recommend longer oil change intervals. Once synthetic oil is used, it is best not to switch back to petroleum-based oil."

 

If the dealer changed your oil, I doubt they used synthetic, esp. for the $60 price. Most likely the conventional kind.

As 1SICK mentioned, you are OK to switch to synthetic at the end of any oil change interval. Unfortunately, this controversial debate of conventional vs. synthetic oil use has been covered MANY MANY times in the past, and way too many threads to look over from the search engine. There is really no right or wrong answer to this topic, so mind as well go with your instincts or with the flow

 

You can switch back and forth till the cows come home. Also Lexus is behind the times with oll here.

 

I was at my local lexus dealership having work done and my mechanic stated that the dealership would be switching over to synthetic oil in 2006..

 

Stick with Syntehtic in your RX300, that engine does not like sludge and synthetic protects against that since that engine ran hot in years 99-01.

 

I'd stick with synthetic my self personally as well. Use either Mobil 1 or Amsoil (I just switched from Mobil 1 to Amsoil). Good Luck!

 

The only RX300 owners who have ever gotten sludge using conventional oil are those who disregarded Lexus's 6 month / 5,000 mile oil change recommendation.

Another group of RX owners who commonly get sludge are those who get their car care education from the Internet instead of from the Lexus owners manual. These owners let the Internet talk them into using synethetic oil and 10,000 - 15,000 mile oil change intervals.

 

Again saber, if the people use a real group 4 or 5, the oil will be just fine. The sludge issues are from people going longer on Lexus oil (mobil) or thinking a group 3 hydrocracked oil (dino) is a synthetic and can go longer.

The 5K mile drains are worthless UNLESS you use a cheap dio oil. Been doing extended drain for about 10 years. Never had a problem if you use a real group 4/5 synthetic oil!

I have oil test, do you? My tests and many other peoples test show you can safetly extended drain if you use a REAL SYNTHETIC OIL! Oh, the process is over 30 YEARS old!

My 98 Es is a sludge engine but my oil tests are just fine. I do not see high NOX / OXD do you? The TBN is still good also.

Time to get out of the dino age my friend.

 

Actually several RX owners on CL & LOC have had the engine sludge problem when all maintenance was performed on time (and mileage) using dino oil. If memory serves saber, you made comments on their threads as well.

 

Not sure if that's true. If memory serves me well, I've read a total of 4 oil gelling issues here. Three out of 4 were recently purchased CPO, obviously caused by previous owners' neglect. One was reported by a newcomer who claimed to have changed oil "religiously." However, he never disclosed his change interval. Then he stopped posting.

 

I will say this, if you try to go 7,500 miles (per lexus) on a group 1 oil in a sludge engine, you are gonna have problems. Advise, stop buying oil at Walfart.