I recently purchased a 1990 Sierra with a 4.3 L engine. When I changed the oil something close to 6-1/2 quarts drained out. The dipstick is not original so I am not sure what the true capacity is. The engine has an oil cooler hookup from the radiator to the oil filter adapter so that might explain the additional oil. Can someone provide the answer?

Also, where is the casting code and engine pad numbers on the 4.3L engine? I am trying to confirm if it is the original engine or a later generation. I searched in the typical places as on a 8-cylinder SBC but there is a lot of plumbing and accessories in those areas. So before I go moving stuff around, can someone please confirm the locatioss?

Thanks.
Mike

 

The only thing I know is the capcity is 5 qts. .... Sorry.

 

I work at a Jiffy Lube. The oil capacity of a 4.3L is 4.5 qt.