detroitguy

Sorry for the double post.Thanks vgr that is very helpful.I imagine I would be safe if I had the trans changed at a lexus or toyota dealer; it seems logical they would use the fluid you reccomend.

As for the radiator stuff, my 1st post afew mo's ago was on how the radiator light comes on very briefly.I did add some anti freeze.I followed the instructions on the owners manual so I used the antifreeze mandated by the manual.However I did mix it with tap water.However the overfill reservoir was already practically full so the amt of water probably equaled lees than 1 1/2 cups.

My brother did maintain the car very well(he now has a 99400ls) and it is my intention to treat the car very good as well so I do appreciate the expertise and suggestions from everyone here

Use only Toyota Type T-IV transmission fluid - around $3-4 a quart at Toyota dealers.  You need to buy 3 quarts although the transmission will need only 2.1 quarts if you drain and refill the transmission oil pan.

Lexus engines do not live or die depending on whether or not synthetic oil was used. But Lexus engines commonly die young due to owner failure to perform preventive maintenance on time on the various engine systems (cooling, ignition, fuel, emission, etc.

For example, the exterior of your LS400 radiator probably looks like this:

http://www.saber.net/~monarch/radjunk.jpg 

The interior water tubes of your radiator may also be partly gunked up if aftermarket antifreeze or tap water was ever used in the cooling system.  And the aluminum coolant pipes and passages inside your engine could already be substantially and permanently corroded if aftermarket antifreeze or tap water was ever used in the cooling system.

Your cooling system thermostat could also now be getting lazy now or be stuck open

Concern and attention to things like this make a big difference in engine reliability and durability, not concern about synthetic oil and oil analysis.

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This is my second post although I do read the forum frequently.I have learned quite a bit here but I do have a few points needing clarfication; apologies if this seems like old stuff .

It seems from reading here that what oil to use is debatable.My brother gave me a 94 400ls with 153,000 mi's.The 1st thing I did was have the oil changed.The shop tried pushing synthetic at a much more expensive price.It was not the expense that dissuaded me.It is the fact that the car has run great on regular 5w oil and I saw no reason to change.Any commemnts?

Also the trans fluid is something I will have changed soon; is the world trans fluid recommended on the 94 ls? should the dealer/trans person know this?

Thanks for indulging me all.I simply love my lexus a real driving treat.

My very generous brother gave me his 1994 ls400.The car is in great shape afew nicks here and therethe seats area a bit worn but all in all avery nice car; way out of my league.

I live in a cold climate.When I start the car sometimes the radiator light comes on.If I shut the car off and start it again the light stays off.The car is not overheating and the heater works fine(hot air blowing from heater) Should I be seriously concerned?The resevoir level is fine.

Btw my brother has a 1999 400 now.