Hey Scotty. Been watching your channel for a while. I have a '10 Suburu Forester with an overheating issue. The water pump, fans, temp sensor and radiator are all working fine. I have replaced the thermostat several times (part from advanced auto). Is it possible I HAVE to use and OEM thermostat with this model/year Suburu? Me and my mechanic have burped the system after install. After driving it for a while it starts to overheat. The bottom hose is cold and the top hose is hot. Also a radiator is "bouncing". I need help please. I am praying you can help me Sir.
If the top radiator hose is hot and the bottom hose is cold. That sounds like the radiator might be clogged.
if bottom hose is cold then radiator is plugged
Take the radiator cap off when the car is cold. Start the car, allow it to idle until the engine reaches normal operating temperature. Look down inside the radiator neck. If the coolant IS recirculating at the neck AND the bottom hose is cold, your problem IS the radiator.
If the top radiator hose is hot and the bottom hose is cold. That sounds like the radiator might be clogged. You could try testing the radiator without removing it by disconnecting the top and bottom radiator hoses. Then stick a garden hose with a towel wrapped around it into the upper radiator port. Then see if water flows though the radiator and out of the bottom radiator port.
@oskool mechanic said the radiator is good.
OEM thermostats are generally best. Did you check the radiator for clogs? Are you sure you don't have a blown head gasket? It's common on older Subarus.
@chucktobias. No clogs in the radiator, head gaskets are good. We can't figure it out.
@imperator I meant radiator hose
sounds like air in the system
@imperator I understand. I can't get the air out when I burp it. That is why I thought maybe trying an OEM thermostat on this year Suburu might work better. What do you think?
As long as the thermostat opens (which you can feel with your hand), I don't see why it would trap air, but sure you can try it. I would also pressure test the cooling system. Did you test for head gasket failure?
@imperator head gaskets are fine. Def air trapped in the system. Purging(burping) won't help. Car runs fine for a little while then starts to overheat. Bottom radiator hose is cold, top hot. Hopefully it is just in need of an OEM thermostat. I heard those have a bigger opening and overall more reliable. Can't find a blockage anywhere.
if bottom hose is cold then radiator is plugged
You might check out the troubleshooting section of the site FAQ to see if there's anything helpful there for your situation.
seems like the water pump is not circulating correctly. Do u have the ac on?
@bzboyd2 my mechanic checked the water pump, no issues.