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Flushing Before Oil Change

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Hello!!! Lexus Members~~~

My friend told me that flushing before oil change can much better my engine in the long term...

He also told me that I could add the flushing liquid and drive it for about 500 miles but the instruction on the can states, 5 minutes in idle before oil change...

Is it OK to drive with the flushing liquid inside the engine and would using this cause any engine problems that could void my warranty?

I'm about to get my first oil change and also thinking about using synthetic oil...the dealer told me to use it on my next oil change (10,000 miles) but just wondering if I could change it in my first change...

Is there any additives that can better protect my car in the long run?


Jack 07 RX350

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Not that I'm an expert, but flushing seems to be a completely unnecessary and dangerous step. With today's oil quality and synthetics available, regular 5K mile oil changes should do it. Synthetic oil makes additives obsolete.

When I bought my RX350 it was astounding that there was no break-in period and no break-in oil used. That is how well engine surfaces are machined and how much more refined are the engine materials.

Driving 500 miles with thinned oil and the debris that the flush causes the oil to pick up doesn't sound like a brilliant idea. Bearing surfaces and rings would be subject to scoring and wear. My old VW used to get a quart of Stoddard solvent (it is non-flammible), idle for 10 minutes, and then an oil change every 3K miles. The oil strainer did not really do much filtering back then and oils were not of today's standard. It probably wouldn't be done today even with an old VW with the boxer engine.

How about pouring a quart of diesel fuel down the intake manifold each oil change to burn out the carbon build up on the pistons and valves. That was an old VW trick that should never be tried nowadays. The emission system (and the neighbors) would go insane.

If you must try something that might help, duct tape a cow magnet to the outside of the oil filter to pick up extra-fine ferrous metal. Then the metal is discarded with the filter. Save the magnet for the next filter of course. It works on my diesel tractors.

Also, use the best oil filter you can buy. Wix (aka Napa) filters work very well on all of my vehicles. Toyota/Lexus filters might be of good quality as well but I haven't seen any research on them.


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  • 2 months later...

Greetings, I think your friend was concerned with an issue the early RX300 had as well as Toyota's with the same V-6 engine (1998-1999). The cooling ports in the block for those engines were made smaller, causing the engines to run hotter. With non synthetic oils, the oil would sludge severely causing major engine problems.

Use a good synthetic oil and you shouldn't have any problems. When in doubt and if your car is a keeper, you can always get an oil analysis done from Blackstone or others for about $25.00. You can trend the wear of just about everything doing that.


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