I last topped off the coolant overflow tank of my SC400 to the proper level about 10 months ago, and I noticed the tank is almost empty today. That's about 1 to 2 quarts "used up" over just 7000 miles- is that normal? The engine seems in good shape, with no coolant in the oil, or white smoke out the exhaust (two tell-tale signs of where the coolant would go if there were problems).

For the time being, I'll top it off- is distilled water a good idea?

And is the "red" coolant the only type I should use? I got a couple of containers of Prestone / Zerex that I'd like to use up, but not if might harm my engine.

Thanks in advance for any advice posted.

 

Replace the pressure cap. If it isn't holding the right pressure, the car could lose coolant under normal operation.

Distilled water? Depends on what kind of public water you have. If it's well water, it may contain minerals that will cause corrosion. If it's snowmelt/mountain river water, it's normally pretty soft and won't hurt anything. But if the coolant is changed regularly, its sacrificial metals will counteract minerals in the water - and that's the point of changing coolant: freeze protection is only part of it, corrosion protection is important too, so good fresh coolant is important even where it never freezes. Coolant wears out in about two seasons.

If you have hard water and a water softener, definitely use bottled water in the cooling system and the battery.

The antifreeze you have on hand may not hurt the engine, but the Toyota stuff isn't all that much more expensive when you only buy it every two years - use the Prestone in the Ferrari -

 

hmmm that seems like a bit much of coolant loss, pressure check your cooling system I'd recommend

I'm in SoCal so I use distilled water because... dude our water down here is hard as hell haha killer water spots

I use Honda coolant in all my cars, Honda makes really good coolant, but you have to COMPLETELY flush out your system because it looks nasty when the red Toyota coolant mixes with the green Honda Coolant

I only use 1/3 coolant, 2/3 distilled water and a bottle of Redline Water Wetter in my coolant- I dont worry about the coolant freezing, I just put enough in to prevent corrosion

 

First off Honda doesnt make coolant they just put there name on it. Second, you shouldnt know how red and green look mixed, cause you dont do it. Third you should use the red coolant, may not last as long but the car calls for it. The green stuff is for Hondas so u should just put it in your CRX and keep it away from a LEXUS.

 

Use the red. The new green stuff may be ok with a alum. engine but i wouldnt chance it. Never take a shortcut like that.

 

hmmmm maybe the reason I said it looks nasty is because I have added Honda coolant to the red Toyota coolant in the past with one of my friends cars

hmmmm so what makes Toyota coolant better on an aluminium engine than Honda coolant?

does Toyota make coolant? or do they just put their name on it?


what kind of shortcut is it using green coolant over red coolant? there is not very much difference in the mixture, both have the same components, one uses a red dye, the other uses a green dye, whats wrong with green?

 

Guyz - Texaco ( Texaco/Chevron ) makes the lubricants for Toyota/Lexus. Very common practice as Exxon/Mobil has made them for GM for years. Just go ask for a bottle of differential lube for your Toyota/Lexus & they'll had ya a Texaco bottle! Nothing wrong with - even though I work for Royal Dutch/Shell, we use lots of their oils for industrial use ( might change now that we bought out Pennzoil ).
As far as the antifreeze goes, just don't mix the older type with the new 'long life" variety. It won't hurt anything but will render the new stuff useless as far as the long life expectancy goes ( it'll still yield standard protection equal to the older "green" stuff ).
The color change was implemented to differentiate between the 2 types ( Texaco's uses red coloring while the GM & Prestone stuff is orange ). Personally, I use distilled water in every water-filled reservoir in the GS ( radiator & windshield washer ) to minimize the mineral deposits. The Redline "Waterwetter" seems to work especially well in older cars which run hot. I've seen a temperature drop of 5-8 degrees in a high compression small block Chevy. Might be overkill in the Lexus but figure it can't hurt. I've been told that the Redline product works by reducing the surface tension of the water so that it flows easier in your cooling system
As for the radiator cap, don't have an SC shop manual but the cap for the 1UZ-FE motor calls for the cap to hold pressure in the range of 13.5# to 17.8# with replacement if the pressure falls below 11.4#. Either check your cap or replace it anyway ( pretty cheap insurance, IMO ). Good luck!