Okay, did a search and found some info, but I am still not certain about the correct procedure. Here's what I did, please comment on what, if I am doing an okay job.

1. Unscrewed reservoir cap and that plastic wingnut at the bottom of the radiator. Only about a gallon drained out, so I started the engine and maybe another 1/2 gallon came out.

2. Unscrewed filler plug at front of engine and with engine running I sprayed water from garden hose into the filler hole at front of engine until the water that came out of the bottom of the radiator is clear.

3. Shut engine off, tightened wingnut at bottom of radiator. Start engine and filled water from garden hose until water came out of resevoir cap opening.

4. Tightened filler plug and let engine ran with heater control on MAX HOT for about 10 minutes. My temp gauge went up about 1/2 way. Shut off engine and drained out water as in step 1.

5. Put back 50/50 mixture.

Question is, is this good enough or I did I leave a lot of coolant left?

 

I think you should check your mixture. Because you left a lot of water in the block the level of protection you have may be as close to 50/50 as you think. There are block drain plugs on each side which, if open and allowed to drain along with the radiator pet ****, will almost completely evacuate the system.

George

 

On some engines those plugs are darn near impossible to get at, which is why there are so many posts on alternative methods. I think what you did was good enough, perhaps the next time, treat whatever is left in the system after a few "flush" cycles as water and add enough coolant to make a 50/50 mix.

For example, if the capacity of your system is 10 quarts, on the final drain, try to drain out 5 quarts. Then add 5 quarts of coolant to ensure a 50/50 mix.

 

On the SC400, the block drain plugs are not too difficult to get at from behind the wheel. They are difficult from the bottom. By the way, be careful when you loosen and tighten those drain plugs. They're brass not steel.

George

 

I too had a pretty tough go of a complete flush as well, & I was pretty damn patient!
Ended up with roughly 40% Toyota Coolant / 60% water mix. Could not believe that there was still so much water in the system although I had made sure that it was newly added water,
I'm in Dallas so this mixture percentage will suffice.

To get a 50/50 mixture it is most likely necessary to pull one of the block plugs.

Damon

 

On my V8, I managed to get 50/50 without pulling any block plugs by using compressed air (well, a ShopVac, actually!) to get a final quart or two out. Buuzy said he did a search- hopefully he saw the post where I detailed the procedure.

 

Carpe Diem--I agree with you. I would mix the new collant on the "high" side to compensate for the water left in block. I would go with a 60/40 or 65/35 mixture to get a 50/50 when installed in rad.

 

Well, since he's in Texas and probably has about a 40% mixture, he's probably ok for now since deep freezes aren't common there. The correction for boilover protection should be made before summer.

George

 

What is the correct water/coolant ratio for sunny california? Why do you have to dilute?

 

50/50 is recommended for most US climates. You would only deviate from that if you're living in a place where it get extremely cold or hot. Antifreeze at this mixture both lowers the freezing point and raises the boiling point of the coolant. Go to your auto parts store and look at the little chart on the side of a gallon. That will show the freezing and boiling points for various mixtures.

You mix because it is normally sold pure, 100% antifreeze, and that has a very low freezing point and a very low boiling point. Mix for your climate. Lexus says mixtures up to 70% are ok for very cold climates.

Be careful what you buy. Some manufactures now sell a premixed coolant that is probably 50/50 (and probably cost more than pure antifreeze? go figure). Obviously if you mix that 50/50 with water you get an undesirable 25% mixture.

Also, there are real differences in antifreeze by type and they probably shouldn't be mixed. If you're interested in this, have a look here:

https://www.clublexus.com/forums/sho...hreadid=107045

There a link to a Popular Mechanics article that covers it pretty well.

George

 

On the Ls400, You will have fill the water up at the throttle body. Otherwise, the vehicle will have an air pocket. Have fun flushing the coolants.
JPI

 

how will I know when there are no more air pockets in the system?

 

Until you don't see any bubbles. Have your radiator cap off and have it running for 15 minutes. It would get rid of the air pocket by then.
JPI