How much coolant should I drain before I remove the thermostat?

Thanks

Sorry forgot to mention this is on a 3.0

 

Just enough.........just kidding. It shouldn't take more than a couple of quarts.

 

Well the t-stat is pretty low in the cooling system, I always just drain it all. I don't find it any harder to drain it all vs draining half. I use a large clean 2 gal container and a funnel with a hose on it right up near the drain point. Then going back in I filter the coolant through a little K&N prefilter just in case there was any small particles in it.

 

I just happen to be draining my coolant yesterday so here's some pics of what I was trying to decribe above:







BTW as you are refilling if you pull one of the high coolant lines (like the one going through the throttle body) it lets a lot of the trapped air out of the system:

 

Thanks. Appreciate the help.

 

If the coolant is over a year old, replace it. If it's discolored replace it. If you live in a hot climate and it's over six months old, replace it. Even factory Toyota coolant is less than $20 for a gallon. It's important maintenece that most ppl skip, heat cycles turn it acidic, plus Toyota was kind enough (not) to pair a brass radiator with an engine that has aluminum heads. Aluminum and brass are reactive to each other, this causes accelerated acid formation. And we wonder why the 3.0's have head gasket issues.

 

Good points, BTW there is an aluminum core radiator avaliable now for the 3.0 trucks. I just installed one from Summit:
https://www.yotatech.com/forums/show...&postcount=514

 

Yeah, I was lucky enough to score my runner used with an alloy rad already in it. FYI on aluminum, it radiates heat into the air much better than brass, something like 3 times as much. Thats why aftermarket alloy rads are usually 1 or 2 cores only, even in four core applications.

 

Hey mt goat, how much was the Evans Non-Aqueous Post Drain Prep Fluid? And is it for aluminum only?

Last question, is that the NPG+? Looks alot like water, does it smell or somethin'? I just never seen clear coolant, but I ain't looked for it either so maybe I's naive.

 

The prep fluid is $27.75/gal and the NPG+ is $32.50/gal, both are mostly clear. Yeah they recommend an Al rad because the core tubes are bigger and the coolant flows through it better. It's about the thickness of 10 weight oil so it doesn't flow thought those small copper/brass core tubes as well. Here's a thread about the waterless coolant if you're interested:
https://www.yotatech.com/forums/f123/evans-npg-waterless-coolant-114994/

 

Thanks, that "quenches" my curiousity much.