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Posted

My 92 LS400 with 166K makes a mild clicking noise that sounds like sticking lifters or valves. A friend suggested changing the oil, but putting one quart of automatic transmission fluid in place of one of the quarts of oil, then changing the oil again after 1000 miles. He says that ATF is essentially high detergent oil and may clean well enough to fix the problem. He also says that this will not harm the engine and that it is an old mechanic's trick. Anyone know what to think of this? Thanks.


Posted

Atf works, but I wouldn't leave it in for 1000 miles....more like 20 miles. Are you sure that it's lifter tap though?

Posted

The ATF trick is an old wives tale. I wish it would die. ATF actually has very little detergent in it, and it's a hydraulic fluid. Just why some "mechanics" insist on using it in engines is beyond me. Read the label.

Don't do it. Lexus builds engines that are among the best in the world, but silly ideas can kill them just the same.

This is my gentle opinion, based on empirical fact. My emotional opinion you don't want to hear.

Use engine oil in the engine, transmission oil in the transmission.

Posted

I agree with not using it in the engine but it is a high detergent fluid.

Not even close to it being an old wives tale as be a fluid with high cleaning additives and properties.

Posted
Atf works, but I wouldn't leave it in for 1000 miles....more like 20 miles. Are you sure that it's lifter tap though?

Wouldn't swear that it is lifter tap because I don't know much about cars. It is a clicking noise that occurs at about 4-5 beats per second when idling in neutral with the air conditioner off. It isn't obnoxiously loud, though.

I've only had the car for three months, and I'm trying to decide if I want to spend money on it. It has 166k. Doesn't need timing or other belts. Interior is very nice and exterior is good. The transmission doesn't shift as smoothly as I'd like between first and second, but it isn't bad. If it seems like everything is OK, I'll get a full tune-up and a few cosmetics and hang on to the car because I like it. Otherwise, I'll sell it and move on.

Posted
seafoam is cheaper, safe, and essentially what you are talking about needing.

I looked up Seafoam, and it looks promising. Do I have to do the brake booster thing? That sounds like it has potential for me to screw up. Or can I just put it into the engine oil?

Also, is there a chance that using this type of product will break loose deposits that are now providing structure, i.e., could the engine be worse off if I get rid of some of the deposits?

Posted

i remember reading somewhere that the ticking sound we hear is the injectors... #5 and #7 injector to be spacific... is this true? i can understand how it could be the lifters but arent they hydraulic lifters? i just got through taking engine repair in school and i see/understand how hydraulic lifters work... i dunno just a thought...

i also have that iritating clicking noise and i would love to get rid of it... ill look into seafoam as well. my local checkers carries seafoam...

Posted
All Toyota's are known for having the fuel injectors tick as they age.

Is some sort of injector cleaning process helpful? Are injectors easily replaced, like spark plugs, or are we talking about real money?

Posted

Fuel injectors make noise, that's what they do. In the absence of any other symptoms, leave them alone. They are very expensive, and "cleaning" them is not normally needed. Real money for sure. Many folks have them checked for perfect spray pattern, and to match flow rates for high power engines, but if your engine idles well -which means near perfect in a Lexus engine - then leave them alone because they are obviously OK.

If your mechanic can't determine the difference between valve noise and injector noise.....change mechanics.

The idea that oil changes will reduce lifter noise - ATF or otherwise - in an engine with fixed shim adjustment is absurd.

Posted

I agree with everything that srk said about the injectors except the last part .

A sticking anything will make more noise.

Just as changing the viscosity of the oil will change the way the motor sounds .

Posted
Just as changing the viscosity of the oil will change the way the motor sounds .

I agree - using 20W-50 (yikes - never do that anyone!) would make the engine quieter because of viscosity. My point was that changing the oil using the same viscosity would not diminish valve train noises, which are noticeable given how quiet the rest of the engine is. The only way to quieten the valve train would be to reduce the cam to lifter clearance (lash), which is established with shims, and not hydraulically as in domestic engines. In those engines sticky hydraulic lifters could sometimes be fixed by rapid oil change intervals, taking advantage of the detergent qualities of the fresh oil.

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