The coolant level in my '91 LS is low, and it would save me a trip to the dealer if I can just use the bottle of Peak pre-diluted Antifreeze/Coolant I have in the garage.

Is it ok to mix Peak with the existing coolant to top off the fluid level, or does the Lexus dealer use a certain type of coolant that I need to stick with?

 

according to Lexus, you can use a 50% water/antifreeze mix of any type of ethylene-glycol based antifreeze to top off your system.

However, Long Life coolants (Dexcool types) CANNOT be mixed with traditional ethylene-glycol formulas.

Lastly, they also say never to use alcohol based antifreezes or water alone.

sj

 

You are better off putting in purified water than Peak. I just had my coolant changed by Lexus in San Antonio, and I noticed the temp difference immediately. However, I know several people down here in Mexico City who add the general coolant they buy at the store, and it does not make a difference in their temperature when they are doing a complete coolant change.

 

I had the same problem just last week in my '94 LS, just make sure you use an ethylene-glycol coolant. Mix it with 50% water. I used distilled water because I figured for a dollar, even if it wont make much of a difference, not having those minerals running through the system would be worth it. Adding the new coolant made a huge difference. The temp needle was flucuating everytime I gave it gas. I'm not sure why I didn't catch it earlier.

 

Another thing you may notice after changing the coolant is slightly faster pickup, as the car does not need nearly as much time to warm up, but again depends on where you live and at what time of year.

 

Thanks. It was a lot easier to use the "ready to use" pre-diluted 50/50 ethylene-glycol based Peak coolant I had in the garage than to go to the dealer just to have the coolant topped off.