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Couldn't remember the last time I'd changed the coolant in the Z, so today I drained everything into a bucket to take a look. As you can see it wasn't terrible, but I'm sure it was time anyway. Bought a bottle of Prestone "Flush and Cleaner," 4 gallons of distilled water, two gallons of Prestone anti-freeze and a bottle of "Rislone Hyper Cool - Super Coolant." Having not done this for a while, the process I followed was to completely empty the system and then refill it with distilled water, and the flush and cleaner. With the front of the car raised to burp the system I ran the car for about 5 minutes with the heater on to get all the bubbles out. The instructions said to go drive the car for 100 miles or so before draining the system again. That's where I'm currently at. Next, I'll drain the system again and refill with a 50/50 mix of coolant and distilled water, and then add the Super Coolant. Hoping maybe the car will even run a little bit cooler. I'll report back.

I can't speak for the Rislone product - but I often use water wetter or VP Racing's coolant additive (can't remember what it is called) and have quite good results.

I recently flushed the SHO's coolant system when I was doing the injectors. Refilled with distilled water and the additive - and have noticed a 10-15 degree drop across the board from the 80k mile coolant that I took out of it.

Also, these are awesome and cheap - and makes bleeding cooling systems quite easy :

https://www.amazon.com/Lisle-24680-Spil ... B00A6AS6LY

I HIGHLY recommend those funnels. I have used them on at least 20 different configurations of cars over the years and they save a ton of headache when it comes to bleeding cooling systems - even on cars with complex cooling systems or customs cooling systems.

Just attach to the radiator or expansion tank with the included adapters, fill level till the funnel is a quarter full and let the car idle till warm and fluctuate the throttle between idle and 3k rpms for a bit. You will be able to see the bubbles, and keep an eye on the level. When done - insert the little plug and pour the additional coolant back into your container.

Now that's clever, Paul. Need to order that set, even if I only do one of my cars each year it would be worth it. I'm saving a sample from each flush to show the progression to clear before re-filling with fresh coolant. The second flush looked almost the same as the first. Will try the third this weekend with just distilled water. Should be much clearer. I'll post a picture when done.

After four complete flushes, this is what the fluid looked like that came out. Though #4 wasn't perfectly clear, as you can see in the picture, I deemed it close enough, and proceeded to fill the system with a 50/50 mix of coolant and distilled water, topped off with the Rislone product. I'll let you know if I see a difference in engine temperature.

You rinsed it 4 times with distilled water?

The first time was just dumping what was in the system. The next three times I filled the system with distilled water, drove 20 or so miles, then drained again. Yeah, I know, not really a flush, more a rinse. Didn't really need to use distilled water, but I had some and bought a couple more gallons at 80 cents a gallon.

Aluminum radiator or Brass?

My Koyo aluminum came with a HUGE warning - warranty void! - if I used any type of "water wetter" product. Nothing but a mix of coolant and water. My Champion aluminum radiators had no such warning though.

Randalla wrote: ↑Fri May 07, 2021 1:49 pm The first time was just dumping what was in the system. The next three times I filled the system with distilled water, drove 20 or so miles, then drained again. Yeah, I know, not really a flush, more a rinse. Didn't really need to use distilled water, but I had some and bought a couple more gallons at 80 cents a gallon.

I don't mean to pee in your Wheaties, but at that point you have done a good job of having only water in the system. Since you can't completely drain the block, adding a 50/50 mix might leave you a little weak. I usually do a 1/2 gallon of straight Prestone and then add 50/50 from there. I have a coolant hydrometer if you want to test and see where you ended up. Probably should be OK since the need for freezing protection is not a worry here.

Gonna run counter to some suggestions and agree with Paul - WaterWetter is indeed a legit product, and I run a couple bottles of it in every cooling system. Also, in AZ, ethylene glycol is only needed for its lubricity and anti-corrosive properties, so I prefer a mix of 75% water, 20% coolant, and a couple bottles of WW.

The titan is a great testbed, considering it tows at 85mph with the AC on full-blast... the cooling system HAS to be top-notch.

Actually, I'm probably more like 50% Prestone coolant, 10% Rislone Hypercool and 40% Distilled water. If I need to top off, I'll be doing it with my remaining distilled water. Doc actually suggested today that using drinking water was better than distilled water because it had trace minerals that had anti-corrosion properties??? Still learning...