Hey guys

have a 2007 h3 hummer luxury

had the trans cooler blow in the radiator so it’s been
replaced now has an external cooler has new radiator, thermostat and cooling temp sensor. Engine light keeps coming with code p0128 which is running too cold, also the bottom radiator hose won’t heat up. Any ideas what it
could be.

 

Welcome to HF. H3 questions all go in the H3 section.

I see you stated the Thermostat was replaced, but did you do the work? Your problem is the TStat is likely stuck open. Either it is defective, not installed correctly, or whoever did the wok put in the old one or none.

Have you checked your coolant level after the repairs?

 

Air in the coolant system. Make sure to properly bleed all the air out before you install the radiator cap.

 

Will get another thermostat under warranty from mates shop who did the job and see if that fixes the problem,


thanks

 

You came here for DIY advice, and have a shop doing the work?
FIND A DIFFERENT SHOP!

or you could tell your "mates shop" to flush the coolant system and bleed all the air from the coolant system.

Diy Flush:

 

Does sound like the thermostat is stuck open or possibly left off if its running that cool.