I replaced my radiator and water pump but
was unable to install a fan shroud; will the lack of a shroud cause problems?
Also, is the thermostat located where the upper radiator hose enters the top of the engine, and must I install one?
You will lose a significant amount of air flow when stationary without the shroud, so it could be a problem in stop and go driving. I don’t know where the thermostat is on this engine (it is often at where the top hose enters the block) but you MUST have one for the engine to function properly.
Here is the thermostat page from the Autozone Isuzu online repair guide.
http://www.autozone.com/az/cds/en_us/0900823d/80/18/42/91/0900823d80184291/repairInfoPages.htm
The upper radiator hose is attached to the thermostat housing for the GM 3.1 V6.
Ed B.
Thankyou for the timely response