Lexmex

Hmm, you might hear the sound more often, especially at idle, but I have known a few vehicles my uncle has worked on with piston slap where the sound wasn't as evident.

afpj

Thanks to all who made suggestions. Cylinder scope showed lots o'crap (carbon fouling) THe dang car only has 67K miles on it. Last I recall seeing this was in something over 100K miles (older Dodge). Spousal unit took it in to dealer to get it confirmed, now they have it to clean. I've been away so didn't get to chat long enough for the bottom line. How much does a decarbonizing procedure cost? Obviously, the fuel injector service had no bearing on this issue. My last vehicle with carbon fouling pinged mainly in the hot weather but with hard acceleration, not this cruising scenario. My wallet is hurting already...

erick3

poop in a cup my fault!

lexus114

I would be anxious to know what they think caused this.

The G Man

THese Toyota V6 are known for carbon built ups and sludge problems.

lexus114

What do you think would be the cause of that?,especially with that low of millage?

Lexmex

Keep in mind that as far as sludging, the 2nd gen RXs have better oil passages than those of the RX300.

As far as decarbonizing, I sort of remember something like this running about $125 USD. I had this done about 4.5 years ago at the Lexus dealer in Naples Florida (Germain) and vehicle ran a bit better afterwards. A few times I sprayed some carb cleaner in (and of course white smoke came out the back) when I was in Mexico. On one such occasion, I blew an ignition coil, but that's because I sprayed too much carb cleaner in there (that was about December 2005). Incidentally, when I had the decarbonization done that was also at about the 60K mark (and I was still running my stock air box with filter unlike now).

Some of you who frequent the RX300 forums may remember that I did a crankscase vent filter modification (proud to report vehicle runs very well since doing this), https://www.clublexus.com/forums/sho...d.php?t=372087

A further explanation of the way the system works OEM-wise is in some of my posts here,https://www.clublexus.com/forums/sho....php?p=3706014

The 2nd generation RX works in practically the same way. This is merely for emissions reasons but does cause a lot of the carbon buildup.

afpj

Lexmex,
You were right on the estimate for decarb. It doesn't ping anymore.

The tech said using non tier-1 gas and using less than super unleaded can cause this. I've only had the car for one year, so I'm thinking the previous owner was using Costco or base gas for a couple years before us. So much for cheaping out on gas. Although I had not seen an increase in mileage since we started using super (91 octane), maybe with cleaner cylinders we'll finally see an increase.

The G Man

Using non-tier 1 can certain cause this, but a lot of the non-tier 1 has actually have the same amount of detergent as the tier 1 brands. I pour a bottle of Techron in everyone of my car once a year for preventative maintenance.

Lexmex

Well, I was lucky to be 'blessed' with Pemex for all those years in Mexico and the difference didn't become as apparent until when I would come up to the U.S. and now being back in the U.S., I have been literally sticking to Chevron Supreme Unleaded. I tried BP and also Shell and would on occasion get a pending A/F sensor issue, something I don't get with Chevron. My girlfriend runs 87 octane from any gas station in her Expedition and it runs fine, but the RX300 seems to be real touchy from my perspective...then again perhaps it's because my RX300 is modified the way it is. Other thing to keep in mind is that in Florida, most gas stations are 10% ethanol, something I really can't dig.

The issue with the decarbonization is primarily oil related. Since I've had the Castrol 0W30 I've had less of an issue when checking inside the throttle body, but when I've experimented with oils like Liqui Moly or Redline (the two that came in between using the Castrol, there was a bit more buildup in the throttle body and also in the baffles (that black piece with the accordion-like section that hooks on to the throttle body). Now that is entirely not an issue given the crankcase vent filters I added.

JamesHuang

iTrader: (1)

Does anyone know if Decarbonizing will help with the engine noise that's common in the RX330's?


Or has anyone recently tried BG44K?



Thanks,
James

Lexmex

BG44K is great stuff for the gasoline but a bit overkill the first time around, thus something like Redline Fuel System Cleaner (I usually see this stuff at Pep Boys) is a better bet first.

Decarbonization goes back to what I mentioned in an earlier post about being largely oil related. If you truly have something mechanically wrong, nothing is going to fix it short of repair.

However, I have found with my RX300 and our 4Runner (2006 V8) that as the oil ages the noise of the motors gets louder as the oil thins out. Consequently, that will inevitably affect the combustion cycle given how the crankcase ventilation system works as I mentioned earlier.

Thus, decarbonization can help, but the first (and cheapest step) would be to run the fuel system cleaner. After that, run a better oil. Castrol Syntec 0W30 I have found has kept my engine very quiet. I am currently testing a Pennzoil Ultra 5W30 and while smooth, I occasionally get chatter out of the engine. I have heard from a few others that running a Redline 5W20 (it is almost like a 5W30 given its chemical makeup) is another one good at quieting down the system.

Decarbonization would be a last step. A lot of people like to use Seafoam for this purpose.

JamesHuang

iTrader: (1)

Thanks Lexmex very much for the input.

So in summary your recommended plan would be,

1. Redline Fuel System Cleaner (Pep Boys)
2. Castrol Syntec 0W30
3. Pennzoil Ultra 5W30 (Alternate to #2)
4. Redline 5W20 (Alternate to #2, #3)
5. BG44K - Decarbonization
6. Seafoam - Decarbonization (Alternate to #5)

Thanks,
James

Lexmex

For me, I usually like to run the injector cleaner after my oil change (assuming you are going to do one), if not just run the Redline Fuel System Cleaner (Pep Boys is about only place I see it, sometimes Carquest).

Lubro Moly (called Liqui Moly in the rest of the world) Engine Oil Flush (Napa sells this, but there are tons of other oil flushes out there) before changing out the oil and filter (run it for about 10 minutes before dumping the oil)

For the oil, Castrol Syntec 0W30 (Autozone or Pep Boys is where I have seen it)

In addition, go with a K&N HP-2009 oil filter (readily available at most auto shops as this is oversized compare to the K&N HP-1002)

Run that for a bit and then report back before doing the other things mentioned.

I'd actually run Pennzoil Platinum 5W30 second for now (jury for me is still out on Ultra). Amsoil 0W30 is a very good oil, but tough to find unless you order online and more pricey (Carquest sometimes has it).

However, at the end of the day, keep in mind my original comment, if you truly have something mechanically wrong, nothing is going to fix it short of repair.

jfelbab

Read about the Top Tier Gas here: http://www.toptiergas.com/index.html

Top Tier was developed by several auto manufacturers to avoid just this problem.

I've found that Shell's V-Power to run the cleanest in my RX. The V-Power has five times the detergents required by Federal regulations. If I burn cheap gas, my RX smells of rotten eggs under moderate acceleration and it has been checked by Lexus and found to be running within specs. I avoid this smell completely when I use V-Power gas.

Shell V-Power info: http://www.shell.us/home/content/usa.../about_vpower/