Michael Smith

I have a 1999 Suburban K1500 with a 5.7L engine. It has front and rear A/C and heat, and I recently did a coolant flush and fill, but I am confused about my experience... I drained the radiator completely, and I took the engine block drain plug out of the driver's side of the block. Lots of old fluid came out, and I waited for it to be completely done draining before I flushed it out and put it all back together.
My confusion is this: the coolant capacity for this truck is listed at 20 quarts. However, I have only been able to get 12 quarts of new coolant (50/50) into the system after this flush. I have gone through several cycles of warming the truck up and letting it cool down in an attempt to "burp" the system, but it just isn't taking any more coolant.
Did I somehow miss getting some coolant out of the system? If so, how do I get a complete drain? The Chilton's manual says to pull "both" engine block drains out, one on either side of the block. I found what might have been another plug on the other side, but it had some kind of sensor-looking thing screwed into it that I did not want to mess with. Could I have missed some fluid by not removing the other drain?
Thanks for your help!
Michael

SabrToothSqrl

you will never get all the coolant out, it's just like oil... it's a numbers game, if you successfully got in 12 new, then you diluted any old with lots of new.

I say it's good 'nuff...

I tried changing power steering fluid... was able to exchange about 1/2 of it at 100,000 miles.

i'll do it again at 150,000....

millenium3

I had the same problem, I was quite puzzled as well. I am sure if the vehicle is not in a certain position it may not be able to drain everything in it. There are a lot of engine components that hold a certain amout of fluid as well and the hoses. I wouldn't be surprized to hear if the hoses contained a 1/8 or more of the total fluid.

Did you flush the system with fresh water before putting in new coolent? This would ensure your not leaving anything behind and as long as your resevoir is full then there sholuldn't be any problems.

Michael Smith

@Millenium3,

Yeah - I first emptied the block, radiator, and reservoir. I then filled it with water and a Coolant system cleaner and ran it for a couple of days (per the directions on the cleaner). I then emptied the block, radiator, and reservoir again. I put everything back together and added approximately 13 quarts of 50/50 Dex Cool.

When I did the flush, I had the front and rear heater cranked up, per the instructions. I'm wondering if maybe there is fluid in the lines leading up to the rear heater core and in the rear heater core itself? Perhaps that accounts for some of the missing fluids.

I did the flush because the truck (which I recently purchased) had the wrong coolant in it. It had the green stuff instead of the Dex Cool. I guess my main concern is if I got enough of the green stuff out to not cause any problems. I've heard that the two do not mix very well.

Anybody have thoughts on that question?

Thank you for your responses thus far!

73shark

If you got 13 qts in then you have a 65% solution which may or may not be as good as a 50%. Check the jug as they usually have a matrix on the back.

I hope you flushed all of the cleaner out before adding the DexCool. The rear heater core probably didn't drain completely which could explain some of the limited refill.