To all who would like to help I'd like to thank you in advance. I have a 2003 LS430 with 180,000 miles. I'm having the timing belt change in a couple of weeks. I've had it replaced at 90K a few years ago. I run full synthetic oil, add a Lucas fuel treatment, change/clean my k&n air filter every 6-7K miles but I still feel like I'm missing something. Is there any other recommended maintenance I should do. Oh and I change the iridium spark plugs every 50K. Is the transmission, power steering, and brake fluid necessary as far as following the dealers scheduled maintenance.

 

I would recommend changing trans fluid too. I do mine every year (around every 15k miles).

 

I always follow the recommended fluid changes to the T.

 

On a pre-2004 LS I'd do a complete AT fluid change every 30k miles - dealer has a machine to do this - it replaces all fluid in the AT and cost about $200 bucks.

I would diy change PS fluid using the turkey baster (or small hand pump) method. Empty out reservoir and refill 4-5 times over the course of a week or two. Do it until the fluid in the reservoir stays nice and clear red in color.

Brake fluid should be completely flushed every 2-3 years depending on condition and amount of driving. Definitely have it done immediately if it darkens in color.

 

1) Here is the Lexus (Canada) maintenance schedule for your car - follow all recommended maintenance, and fix other problems as they come up, and your car will last a long time - http://xws.xtime.com/xmmmenu/?varian...&estimate=true

You don't need to change transmission or any other fluids earlier than they recommend unless you have a problem. 2001-2003 transmission fluid interval is 96000kms/96 months. If you have a problem with a component, diagnose and identify root cause first - no sense spending time and money on changing fluid out for no reason.

2) Save your money and ditch the fuel treatment and K&N air filter. If you live in a place bigger than a remote village, you likely are within driving distance to a Top Tier gas station. I think you would have a tough time proving ANY fuel treatment offers any benefit over a Top Tier gas.

The OEM engine filter and intake box/tube is designed for cold air intake from the front grille and is engineered for specific flow and turbulence characteristics. The purpose of the engine filter is to prevent small and large particles from entering the engine. See https://www.clublexus.com/forums/7379032-post9.html for more info.

"Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy."

Independent tests show that compared to the filter paper media in most OEM paper air filters, K&N's cotton gauze filters have been shown to clog more quickly and to let more particulates pass through into the engine. I have also read on several forums that the oil on the K&N filters can end up coating the MAF sensor and other parts downstream.

K&N's air filter is meant to be periodically washed and recoated with oil. K&N offers a million-mile warranty and says its air filters are more environmentally friendly than ordinary filters, since they never need to be replaced and thus do not end up in landfills or incinerators. K&N claims owners can drive for 50,000 to 100,000 miles between cleanings.

Since you are not using OEM filter and intervals, you are not following what the Lexus engineers say is best. Since you are using K&N, cleaning/changing every 6-7k miles, you are not following one of K&N's main selling points either and are likely exposing your engine to contamination. Why spend extra money to intake warm air and decrease power, potentially throw off the readings from your MAF sensor, and to decrease the life of your engine?

3) Changing the OEM iridium spark plugs every 50k miles is a waste of money. Denso (who invented and manufactures the OEM plugs) and Lexus recommend changing at 120k miles. You are changing the plugs at 42% of the lifetime.

4) Regarding the power steering fluid, there is no service interval specified in the manual or maintenance guide. Directly from Lexus: "The power steering fluid does not need to be replaced under regular use. The fluid should only need to be replaced if the power steering pump has failed and there is metal in the lines and power steering rack."

Even the power steering rack manufacturers like Dana, see no need to change this fluid unless there is a significant problem or a massive leak.

5) Regarding brake fluid, you should change it every 36 months or every 48000km, whatever comes first. It absorbs air/water over time, not only use. One of the characteristics of polyglycol brake fluid is that it is hygroscopic, meaning it has a propensity to attract water. Water can be absorbed through rubber hoses and past seals and past the vent in the master cylinder reservoir cap. Moisture in the hydraulic circuit reduces the boiling point of the fluid and causes it to vaporize. In addition, moisture causes metal parts to corrode resulting in leakage and /or frozen wheel cylinder pistons.

6) If you look at the maintenance schedule, rear differential fluid is covered - the interval is every 32000kms. Please read the maintenance guide relevant to your model and year to be sure.

7) MAF sensor and throttle body cleaning - this is not covered in the maintenance guide but I do mine every springtime.

I only change my front and rear cabin air filters when the car is vacuumed and clean but I can tell that the circulating air isn't fresh. I change the seat filters annually/biannually depending if I think airflow through the seats is reduced even after a good vacuuming.

The people taking your money aren't going to be the first to tell you that you are wasting your money. If you don't want to waste money, do your research, understand the mechanical workings of automobile components, inspect your vehicle inside/outside/underneath often, and be guided by the manufacturer's recommendations. Then you will know what to change and when.

 

What about changing the rear differential fluid?

 

Boomer - good point - manual has mileage for that also. Think I did mine at 30k

 

clean the MAF sensor and throttle body