LS4Lexus

My '91 LS has only gotten drain-and-refill service at the local Lexus dealer for all applicable fluids through 75K miles. I'm approaching 90K now, and was thinking of taking my car elsewhere to have flushes done instead.

I was warned, though, about doing an ATF flush at 90K miles if it has never been done before. The guy also said if the ATF hasn't been regularly changed for an extended interval, it's best just not to touch it at all.

With the knowledge that an '91 LS has only gotten drain-and-refills through 75K miles, which types of fluid changes would noticeably benefit from a flush at 90K miles? Or is it better to simply keep on doing drain-and-refills?

HarrierAWD

Are you talking about a coolant flush or a tranny fluid flush?

LS4Lexus

Coolant, transmission, brake, differential...I'm kind of wondering about them all.

But the specific recommendation I've heard against doing a flush was for the ATF.

HarrierAWD

Correct. Do not flush transmission. That'd push debris to where it shouldn't be. Just drain and fill.

Now, some old ATF will stay in the torque converter. That's fine as long as you drain and fill at regular interval. Some people really love their cars would do it twice (drain and fill, drive around a few miles, then drain and fill again.) It's not necessary. Don't use the AAMCO powerflush, that'll do more harm than good.

Differential is drain and fill.

Brake is "bled", essentially drain and fill. The tech will have to make sure no air bubbles are trapped in the brake line.

Coolant is a flush every 2 years or 30k miles. Some choose to drain and fill because Toyota coolant seems to keep the radiator very clean. I prefer flush because it also pressure test the cooling system in the process. I'd rather spot a leak at the dealer than on a dirt road in wolf country.

LS4Lexus

HarrierAWD - Thanks for the comprehensive post!

Is it also advisable not to do a flush for the coolant if the car has only gotten coolant drain-and-refill through the first 75K miles? Or does that only apply to the transmission?

HarrierAWD

At 90K, I'd flush the coolant. Like I said, it's a good opportunity to pressure test the entire cooling system.

Don't flush the transmission, ever. The only time you flush tranny is when somebody put Hershey's chocolate syrup in it. Of course you should drop that somebody off in the wolf country first.

Bluesman

I decided to go with a flush just before reaching 90k miles. I had the service performed at a Toyota dealer. According to the records of the previous owner, a drain and fill was done @ 75k miles. The ATF was just about black. I haven't had any tranny issues to date (knock on wood). Obviously, drain and fill vs. flush is often debated. If the ATF didn't look as bad as it did, I would have decided to have the drain and fill instead.

I realize that this doesn't give you a concrete answer that you are seeking, but I thought I'd share my story.

saber

Draining and refilling the pan every 15-25,000 miles with the Toyota Type T-IV fluid will keep the fluid and transmission looking and running like new for hundreds of thousands of miles. Service shops will rarely tell you this because they stand to make alot more money for nearly the same amount of labor if they succeed in talking you into a flush job.

Same deal with the cooling system. A Toyota cooling system will stay immaculately clean by just draining and refilling the radiator every year or two with a 50/50 mix of the Toyota Red Long Life coolant and distilled water. Since the system stays immaculate, flushing is never needed. However, the EXTERNAL fins of the radiator can become blocked with dirt and bugs and cause an engine to run hotter. Here's how filthy the radiator of my '91 LS was after 101,000 miles: http://www.saber.net/~monarch/radfilthy.jpg Service shops rarely will point this out.

Lexmex

One of my Lexus dealers had put in a Castrol ATF on a drain and refill. Luckily, my next Lexus dealer caught it and did drain and refill until all Toyota Type-IV, not 100% accurate, but they did their best at 47K. No problems.

I recently did a flush at 70K at another Lexus dealer and no problems to date.

HarrierAWD

If the ATF were black (should be cherry red,) obviously something is wrong with the tranny or the previous owner didn't do jack.

In that case, I'd do two drain-and-fill in a row, not a flush.

HarrierAWD

Just wondering... how did your next dealer catch it? Did they have a way to test it, or was your tranny acting up?

Thanks.

HarrierAWD

Gosh saber, did you ever clean it? I don't want to know what your bathroom look like.

LS4Lexus

How about brake fluid? If I remember correctly, a shop once told me only to change it out when replacing brake pads. Do you guys change it more regularly than that?

bob2200

It depends on how often you change brake pads

Lexus recommends every 2 years. Surprisingly, my local Lexus dealers recommends every 4 years. My last Mercedes-Benz had a recommendation of every year. I changed it out every 2 years with my M-B and am doing it every 2 years with my Lexus.

lexusk8

You don't necessarily need to change out your brake fluid when you change brake pads, unless you're overdue for a brake fluid change (recommended change interval every 30K miles).

However, when you change brake pads, it is a good idea to remove a little bit of brake fluid out as you apply pressure to the brake piston to properly fit the caliper assy to the rotor. As you undergo that action, you want to watch and make sure the brake fluid doesn't overflow.

Here's a useful link to learn how to change brake pads and rotors in an LS: http://www.lexls.com/front_brake_rotor.html