overheating

Radiator keeps backing up into the resevior but temp gauge is normal just changed thermastat didn't help even flushed the cooling system 05 PreRunner 230000 miles

 

Maybe the radiator cap is bad and not keeping the system pressurized? Have you checked your fan clutch?

 

Sounds like a cyl head gasket. Sorry!!! Have your coolant checked for hydrocarbons. Look into the rad with the truck running. if you see tiny bubbles in the coolant this is your problem. Good luck! I have had this problem with my subaru forester. If you leave it too long the top rad hose will fill with gases and the system will stop flowing.

 

get the cap pressure tested, or just toss a new one on there.

if not,then have the system pressure tested. 230k miles is ALOT!! nicely done!

 

X2 A good shop will have a gas analyzer just get them to sniff the rad. dead give away.