RX400h

I know this article concerns an LS model but it contains lots of good info regarding control arms and worn bushings. http://www.lextreme.com/bushing.html $1500 seems very excessive and this is something that I believe most local shops can do for less dinero.

Thanks, Steve. I think I'll order a set. The rains are accummin! Dave

Based upon those facts, I, too think one or more tire is at fault.

Katz, I once had Sumitomo tires on our Nissan Quest. They started humming at around 8000 miles or so. My Bridgestone Alenzas that were on our RX400h started humming before they had much more than 30,000 miles. Every single time I've heard this kind of sound it was because of the tires, not necessarily because they were worn out, although in one case, it may have been because the tires were wearing unevenly. An alignment that is out of wack could very well cause this to happen. Hitting a curb hard enough can do this or damage a wheel bearing. I'm assuming this hasn't happened to you but if it has, your alignment could need correction or bearings replaced. How did your Goodyear tire wear? Did you ever have an alignment done? I'd be surprised if Costco has a rule about replacing tires with OEM models only but I never had my tires replaced there so I'm not sure.

Very seldom is choosing OEM tires your best bet when replacing worn out tires. Most will not last as long as good replacement tires (as explained to me by a Discount Tire manager) My guess is that your tires have internal issues - probably a rarity among Michelin tires but entirely possible. I would make a bet with the Costco manager - if replacing the tires with a different model solves the problem, you walk away without paying a dime. If it doesn't, you pay for their remounting cost. Odds are that you would win the bet.

I am considering ordering silicone wiper blades and am wondering if any of you has tried them. Technically, they should last longer by not degrading from ultraviolet rays, although I'm not sure what kind of wear rate they will have. Thoughts?

Jim, do you know if any major tire stores have this equipment?

Isn't there an aftermarket part that will allow the override?

Many "Long life" oil filters have 40-70% more dirt/contaminent-holding capacity. Some of those long-life filters (like Fram Extended Guard) claim that they can last up to 10,000 miles. Now, if that filter can hold 70% more than the average filter, you may be pushing your luck if you think an average oil filter can last 10,000 miles. I suggest that if you do go 10,000 miles between oil changes that you make sure the oil filter you use is at least advertised as a long-life filter.

That's good to know about the extended life filters. My Corvette has an oil life monitor which is much more sophisticated than a miles driven setup. The Corvette's monitor algorythm takes into consideration engine operation length of time, oil temperature data, and other factors. Of course, it assumes all OEM air and oil filters are used. The maximum length of time between oil changes, regardless of the monitor's oil life remaining percentage is 12 months. But I agree that synthetic oil may not be finacially justified if changed every 5 months or 5000 miles (in our Lexus vehicles).

Correct me if I'm wrong but most oil filters, if overloaded with contaminants, will allow oil to bypass filtration to avoid overpressure conditions. If this happens, the oil will indeed contain significantly large particles that could accelerate engine wear.This would certainly be evident in oil testing data.

Don't forget the oil filter. Most oil filters are not designed to hold 10,000+ miles of dirt in them. That is why I'm sticking to a 5000 mile interval, even with synthetic oil. The only way to know for certain whether your filter can go the distance is to have an oil analysis done.

I,too have a local shop but I would not take a sophisticated vehicle like the RX or the Corvette in for "involved" repairs. I feel for those tasks, the dealership is most qualified (in many cases).

I'm a bit surprised your water pump failed at 77,000 miles. Then again, many people have their water pump replaced at 60,000 or 90,000 miles when their timing belts are being replaced. My CD player is back in the "ERROR" mode so I guess it will have to be replaced one of these days.

Horsepower from the ICE dominates acceleration at the upper end of the rev range. The electric motors produce greatest torque at 0 RPM, so while the level battery charge does make a difference in acceleration, octane rating and ambient temperature also play a role that can be felt when the throttle is held wide open.

Actually, it does affect performance. However, your style of driving will determine whether it makes a significant difference to you. If you decide to race a Porsche Cayenne or BMW X5, then yes, you will appreciate premium fuel in the tank. :)

My guess is that your 2011's rated horsepower requires the use of premium fuel. The 2012 may be rated (horsepower, torque, and fuel economy) using regular fuel, which makes sense since most hybrids are rated to run on regular grade fuel. Most higher-end vehicles made since the late 80s incorporate electronic knock sensors that will instruct the engine's ECU to !Removed! timing if knocking/pinging is detected. It is because of these sensors that many vehicles can run on lower octain fuel than is recommended by the manufacturer.

Are you sure this is not happening on the same stretch of road? I feel the same thing on a certain stretch of road in our neighborhood. It dissappears 2 miles down the road.

How many miles are on the odometer?

If you look at the end result of my calculations, you can see that Rey's 255/55/18 tires are in fact, taller by a noticeable 0.86 inches. If the aspect ratio and wheel diameter remain the same, as width increases, so does the tire height (diameter). Of course, the tire width increases as well, so at some point the tire will interfere with a suspension component unless wheel spacers are added. Keep in mind, too, that larger tires are heavier tires and that extra weight may be centered further out towards the circumference - undesireable for a number of reasons.

Here's how you calculate tire height: (Tire width*aspect ratio*2 + wheel diameter (in milimeters) then divide by 25.4 to obtain the height (diameter) in inches thus, 235/55/18 tires = 28.18 inches 255/55/18 tires = 29.04 inches Note: use .55 when multiplying the tire width by aspect ratio

You can get away with lower octane gas when the weather is colder and intake air is more dense. Combustion cannot happen without both fuel and air with air making up a much higher percentage of volume.

Bob, Most tires "feel" good, initially. The real test comes after they have 10,000 or more miles on them.We'll be standing by. Dave

Did the dealership service advisor mention what caused the blockage?

Torrents?