monarch

The thermostat gasket on Toyotas typically fits on the thermostat itself; therefore you may not be able to seal the thermostat housing to the engine if you remove the thermostat. If I owned your car I'd be concerned about the rough idle. I'd want to get the engine's compression tested to make you don't have low compression on one or more cylinders due to a leaking head gasket, mechanical engine damage or excessively tight valve clearances, all of which would tend to contribute to the engine's tendency to overheat. If the compression tests out good (high and even on all cylinders) and you have verified the spark plugs and ignition timing are good and that the catalytic converter isn't clogged, then I'd look more closely into restricted coolant circulation . Another idea: Idle the engine for 10-15 minutes with the radiator cap off and watch the temperature gauge. If the temperature gauge rises way above the 1/2 point on the temp gauge dial, but the coolant doesn't begin to boil over then your actual coolant temp is normal (180 degrees) and the temp gauge is faulty.

Based upon what they read on the Internet, even some late model Toyota / Lexus owners are becomng convinced they need to "decarbon" their engines are using Seafoam or Water Injection. Like today on the Toyota 4x4 Pickup Discussion Group a 2003 Tacoma owner wrote: "My 2003 Tacoma with the 2.7 engine is carboned up again. I do not know where to introduce the Seafoam or water. Could someone please advise?"

Your owners manual says to check the engine's valve clearances every 60,000 miles. The tapping noise you describe sounds like some valves that have somewhat loose clearances. These noises are typically a bit louder after an oil change Only API GL-5 gear oil should be used in the differential, never Dexron. You could use 80W-90, or 85W-140 conventional or 75W-140 synthetic. The 80W-90 would be best for cold winter climates and 85W-140 or 75W-140 best for mild winter climates and hot summers.

Here is what a Toyota valvetrain typically looks like after 270,000 miles of running on conventional oil that was changed every 3-5,000 miles http://i5.photobucket.com/albums/y189/mastertech/cor.jpg As you can see, there is just a light, harmless coating of varnish and no trace of sludge.

The Nov. 2005 issue of Consumer Reports has great info and ratings on tires. The Gooyear Tripletred and Michelin X (latter available only from Costco) were tops in ride comfort and quietness and I believe the Tripletred edged out the Michelin in wet traction. The Michelin MXV4-Plus (available everywhere) is very similar to the Michelin X. I consider Consumer Reports better than tirerack.com as a source of objective information. For example, CR correctly reported the Goodyear Comfortred delivers mediocre ride comfort whereas Tirerack.com erroneously reports the Comfortred is tops in ride comfort. I found out the hard way CR was right about the Comfortreds delivering a rough ride.

What is your definition of "Meticulously Maintained"? My idea of "Meticulously Maintained." is following the severe service schedule listed in the owners manual including performing most other required maintenance services more frequently than the minimum intervals listed in the owners manual or scheduled maintenance guide. Toyota owners who follow the severe service schedule are rewarded with low rates of oil consumption for 500,000 miles that are approximately as follows: 0 - 50,000 miles 1 quart every 5,000 - 10,000 miles 50,000 miles 1 quart every 4,000 - 6,000 miles 100,000 miles 1 quart every 3,500 - 4,500 miles 200,000 miles 1 quart every 3,000 - 4,000 miles 300,000 miles 1 quart every 2,500 - 3,000 miles 400,000 miles 1 quart every 2,000 - 2,500 miles 500,000 miles 1 quart every 1,750 - 2,250 miles A dirty throttle plate can also adversely affect oil consumption so it should be cleaned about every 30,000 miles to maintain optimum power, fuel economy and low oil consumption http://www.saber.net/~monarch/tbclean.jpg

Has the clutch pedal freeplay and pushrod play been adjusted using the procedure outlined in the factory repair manual? These adjustments are pretty critical to prevent the car from jerking and bucking when you release the clutch pedal. It can also be helpful to bleed the clutch fluid from the clutch release (slave) cylinder.

Better to achieve what? Both oils are capable of enabling a Toyota engine to last 30+ years or 500,000+ miles, but the vast majority of owners don't plan to or want to keep their cars that long. And most of the owners who do want to keep their cars long term will end up ruining their motors in other ways long before 500,000 miles regardless of whether or not they used synthetic oil. The Toyota engineers understand all this too and that's one reason why they don't equip new Toyotas with synthetic oil. Instead, they try (usually in vain) to get car owners to focus their attention on preventive maintenance items that REALLY matter to engine longevity like using only factory antifreeze, factory thermostats, factory spark plugs, factory air and oil filters, etc, checking oil and coolant levels frequently, having engine valve clearances checked every 60,000 miles, don't mod the engine in any way and to call a tow truck if the motor starts to behave abnormally in any way (uses more gasoline, runs hotter than normal, makes odd noises, misses, bucks, etc).

No it's not likely your car can be fixed without spending thousands of dollars. In May you made a decision to buy a luxury car with 150,000 miles and no preventive service records. Such cars commonly have severe mechanical wear and tear and are on their last legs. Your car, for example, overheated just two months after you got it and then you kept on driving with the temperature gauge ABOVE the red zone which is like pounding nails into the coffin of an already worn and neglected car. More recently you've been driving around with the motor "knocking/pinging from the engine, heavy vibrating and lots of smoke from my exhaust" which is like which is like pounding even more nails into the coffin. At this point I think you have 3 choices: 1. Spend thousands of dollars to have a good used engine installed + all new emission system componets which were likely burned up by the overheating / pinging etc. This would probably be a mistake since your transmission and other mechanical parts of the car are likely worn too due to years of preventive maintenance neglect and would soon need to be replaced as well. 2. Install new spark plugs to try and get the motor to run half decently so that you can try and sell it to another young buyer who, like you, was willing to buy a luxury car with 150,000 miles and no preventive service records. 3. Part out the car or sell it as is in non-running condition.

You don't have to worry if you are the original owner. The owners who have to worry are the ones who bought their cars used without examining the service records to verify if the oil was changed at least every 6 months or 5,000 miles. If not if would be a good idea to pull ONE valve cover for a peak at the valvetrain. Sludge does not build up in a well maintained Toyota engine.

It's pretty routine for service shops of all types to overfill engines and transmission with oil (that way they get to sell an extra quart of oil). 2.1 quarts drains out of my '91 LS400 transmission (if it is not overfilled) and it is equipped with same transmission as your '94 SC400

Are you intellectually open to using what the Toyota engineers recommend? If so, the weight and minimum API grade oil to use is marked on your oil filler cap. The factory fill oil in all Lexus's is dinosaur oil. If you are not inclined to follow the Toyota engineers recommendations then you can search the forum archives and spend days pouring over 1,000 opinions from over 100 Lexus owners on what oil and weight to use.

It says right on the cap of your PS pump reservoir cap to use "Dexron ATF". So any Dexron II or III automatic transmission fluid will be OK. Yes the factory fill fluid in the PS pump reservoir is clear to light tan in color. Many owners mistakenl think the tan color means the fluid is dirty, but it's not. Even the factory fill fluid in a 2006 Lexus is light tan.

EGR valves do not get badly carboned up and engines do not sludge if the owner buys the car brand new and maintains it the way the factory engineers intended. I agree throttle bodies get gummed up over time. The factory engineers are aware of this and have developed a product to clean up the throttle plate deposits without risk of harm to the engine or emission system: http://www.saber.net/~monarch/tbclean.jpg

Was a genuine Toyota thermostat and thermostat gasket installed? Do the electric cooling fans come on when the temperature gauge gets about 1/2 the way up the dial? Under what driving conditions does it overheat? Is the coolant a mixture 50% antifreeze and 50% water?

I agree. I'm one of hundreds of Toyota 400,000 mile owners http://www.saber.net/~monarch/463.jpg who doesn't use additives. Simply operating and maintaining a Toyota engine the way the factory engineers intended (which means just say NO to aftermarket mods / alterations / products) prevents excessive power robbing deposits from forming on parts like the intake valves, the EGR valve and fuel injectors to begin with. I don't think the pro mod, pro additive owners ever stop to think and ask themselves: "Hey I wonder what the intake valves, EGR valve, fuel injectors and other parts of a Toyota engine would look like after 400,000 miles of being maintained the way the factory engineers intended"?? or "Hey, I wonder why the aftermarket product and additive salespeople won't show show the public photos of Toyota engine parts after 400,000 miles of being maintained the way the factory engineers intended"?? or "Hey, I wonder why the aftermarket product and additive salespeople don't show show the public photos of Toyota engine compression test readings after 400,000 miles of being maintained the way the factory engineers intended"?

Here's what the Asian automakers think of additives: http://i5.photobucket.com/albums/y189/mastertech/nissan.jpg http://i5.photobucket.com/albums/y189/mastertech/nis.jpg

All Toyota oil filters have an extra thick and heavy filter shell regardless if they were made in Japan, Thailand or the USA. I presume this feature is intended to build in an extra margin of safety against bursting during demanding driving conditions that create high oil pressures. I know from reading Motorhome and Trailer Life magazines that there have been some incidents (involving aftermarket filters) of filter shell breaches during demanding hill climbs that resulted in sudden catastrophic loss of motor oil and engine destruction. The PureOne's gasket is not tightly secured to the filter so you can easily pluck the PureOne's gasket right out of the filter using your bare fingers and stick it to the side of any metal or glass surface. It will cling real good to a verticle surface that's oily despite being teflon coated. But you can't pluck the Toyota filters O-ring style gasket out using your fingers and even if you use a tool to pluck it out you can't make it stick to any verticle surface even if it is thickly coated with oil. All Toyota oil filters have had this feature going back 30+ years regardless if they were made in Japan, Thailand or the USA. I feel the many "oil filter study" type websites on the Internet actually dumb the public down by neglecting to tell them about the special features of Asian car OEM oil filters. However, I am not surprized since the people who author "oil filter study" websites don't work for the Asian automakers.

What detectable engine wear benefit will a Lexus RX or ES owner gain by purchasing a Purolator PureOne oil filter over a Toyota 08922-02011 filter? I've been using the Toyota 08922-02011 for 467,000 miles and my '92 Toyota 4 cyl engine still performs like new with like new engine compression readings. So what detectable engine wear benefit would the Purolator PureOne have given me? Here are some negative aspects of the Purolator PureOne compared to the Toyota 08922-02011: 1. Purolator PureOne costs $5.99 at retail stores like Pep Boys. Toyota 08922-02011 is $3.89 from 1sttoyotaparts.com 2. PureOne PureOne lacks certain heavy duty construction and thoughful accident prevention features of the Toyota 08922-02011. Features like these: http://i5.photobucket.com/albums/y189/mastertech/fbrick.jpg http://i5.photobucket.com/albums/y189/mastertech/ftread.jpg Toyota is currently phasing out the Toyota 08922-02011 and using the Denso 90915-YZZD1 in its place. I have complete confidence in the Denso 90915-YZZD1 based on the sterling track record of Toyota and Denso parts.

On the black power steering reservoir cap it says "Use Dexron ATF" . That means use a Dexron II or III Automatic Transmission Fluid. Is that what has always been used in the system? Or some other type of product like power steering fluid purchased from an auto parts store? Is the serpentine drive belt old or in newer shape? Is it a Toyota belt or is it aftermarket? Is the power steering pump the factory original or an aftermarket pump? Since all the early 90's factory original pumps have developed leaks by now, you might either have an auto parts store pump, a new pump installed by a Toyota/Lexus dealer or your factory original pump was resealed by someone who bought and installed a Toyota power steering pump reseal kit.

What I'm talking about is the owner who said "I have driven it 3 times with the coolant boiling and nothing happened to the engine." And then other owners agreed with him that nothing happened to the engine including owners who use synthetic oil. The reality is overheating warps the aluminum cylinder heads and compromises the integrity and potential life of the cylinder head gaskets as well as the life potential of other gaskets on the engine. Not to mention cooking the exhaust valves and valve seats etc. These owners who think "nothing happened to the engine" are going to end up finding out the hard way they don't stand a chance of ever becoming a member of the Toyota 400,000 mile club even if they use synthetic oil. And when their cylinder head gasket finally does let go and the engine runs hot again what are these owners going to do? They're going to keep on driving anyway because they think ""nothing horrible is happening to the engine unless the temperature gauge is deep into the red zone and coolant is shooting up into the sky"

Did your RX receive oil changes at least every 6 months or 5,000 miles since the day it was brand new? If so sludge is IMPOSSIBLE. 99.9% of RX's never get sludge. If you are still concerned, pay someone $50-100 to remove one of your valve covers so you can look and see whether or not there is any sludge. If no sludge, then there's no legitimate need to spend $2,000 on an extended warranty. There's no legitimate need to use synthetic motor oil either if you plan on changing the oil at least every 6 months or 5,000 miles. The terrible side effect of spending money on extended warranties is that the car owner considers it like a security blanket and is much less likely to pump money into frequent preventive maintenance. Example: The owner who buys an extended warranty will likely stretch engine oil and filter changes out to the 6 month / 5,000 mile limit instead of using a more frequent interval like 3-4 months or 3,000 - 4,000 miles. And instead of changing the transmission fluid every 15,000 miles they won't even bother with something like that until 60,000 miles or more. And instead of replacing oxygen sensors at 80,000 miles or so they'll wait until they are so worn the check engine light is tripped. End result: the car of an owner who bought an extended warranty will have alot more mechanical wear and tear after 100,000 miles compared to the car of an owner who spent $2,000 over the years on more frequent preventive maintenance.

I'd go with either the Turanza's that wwest recommeded (assuming he tells us which specific Turanza was so quiet) or the Michelin MXV4-Plus (assuming it's available in an 18" size). The MXV4-Plus is probably more expensive, but has excellent treadwear characteristics in addition to a smooth, quiet ride. Lexus fitted some of the 2004 RX330's at the factory with the MXV4-Plus

It's amazing the same owners who insist on using synthetic oil because they think its going to extend the life of their engines are the same ones who turn around and overheat their engines thinking it does no serious harm.

The price is very low considering how well the car was cared for. About the only mechanical problem you'll likely have to deal with is a leaky power steering pump. New pumps occassionally can be found on ebay for $200-$300. If you have mechanical experience, you can buy a pump reseal kit for $30 from a Toyota dealer and redo the seals yourself. It is important to determine whether or not the pump is leaking considerable amounts of fluid (there will be telltale drips of power steering fluid on the floor underneath the car) because the fluid drips onto the alternator, shorting it out and can leave you stranded without warning. I'd also check to see if coolant was ever changed. Neglected coolant has, in some cases, led to a leaky heater core which can cost over $2,000 to replace because of the many hours of labor needed to tear apart the dashboard to gain access to the heater core