I am going to be changing out my enging and was wondering about how many gallons i need to coolant I need to buy to put back in after i put the new engine in.

1990 GMC Jimmy 5.7l

 

i would guesstimate if you buy 2 gallons of concentrated antifreeze (so 4 gallons with water) that should be sufficient. but there are variables sometimes k5 blazers have thin little 1 core radiators and ive seen them with those gigantic diesel 4 core ones that would probably take all 4 gallons.