Lower Rad Hose Question
 

Yes this will sound stupid, but i am new to imports having always owned and worked on domestic vehicles, Although this oversized go-kart is a lot of fun to drive i find mechanically, this car baffles me at times.

I have an 02 Protege 5, 2.0L, 5-speed, after driving for an hour i would expect the lower rad hose to be hot, just as the top one, but this isn't the case, the lower hose is cool, while the top one is hot. this would leave me to believe that, a). either the thermostat is stuck, or b). the flow is out from the bottom of the rad into the engine, through the engine and back out the upper rad hose to the rad.?? (at this point it wouldn't surprise me)

The car isn't over heating, the needle sits at half as it always has, I blew a thermostat on it once and the heat shot straight up, so i am sort of leaning away from a bad thermostat at the moment.

any insight on this would be great, Thanks

oh yea, does anyone know if it is possible to buy metal rear fender sections, or fiberglass if necessary, yes you know what sections i mean, I haven't been able to find any, you would think that is a part they could start making a killing on

The difference your feeling is normal if your cooling system is in good shape, if you would have a water pump issue the top hose would not be hot, maybe warm but not hot. Now you did say COOL and not cold, cool to me means there is heat there but it is cooler than the rest of the system, cold would mean no flow if top is hot but cool would indicate flow. And yes if your thermostat was stuck closed it wouldn't get hot(top hose) and if it was open it would never get hot still(again warm though). Now if BOTH hoses were hot that usually means your radiator is scaled up inside and preventing efficient heat transfer or your airflow through is blocked. Sounds to me like you should have no worries at all with your car's cooling system at the moment, also coolant flows into the engine from the bottom hose and comes out the top hose, old low power cars never used a water pump and relied on the thermo-siphon principal where hot water exiting the top of the engine would pull cooler water in from the bottom of the radiator (also why most old radiators were vertical core and not horizontal core to facilitate this flow) but once power levels went up this system could not remove the extra heat produced so water pumps were installed.

Thanks, i thought i was losing my mind with this thing, when i say cool, it isn't cold, but you can grab it and hold onto it. I'm just trying to figure out where my coolant went,

over about 2 months it lost about 2 liters of antifreeze, i went under and couldn't find any external leaks, i also checked the back of the engine and there was no staining, it was still clean, even the plastic under the engine was clean and dry.

Oil isn't discolored, I'm not noticing any white smoke coming from the exhaust and i don't smell burnt antifreeze, or i haven't noticed it yet, and i haven't noticed a loss in power, I'm not sure if that is just due to having a CAI in the car and it is still able to help compensate,

I'm at a loss as to why i lost antifreeze. When the intake in my bonneville blew out there was a noticable drop in fuel mileage and performance, but i haven't really experienced that yet, or is this just another quirk with these things? Although i still have to pull the plugs and see what color they are.

How long ago was the thermostat issue? Was it two months ago? Did you refill it with coolant and it took 2L? Is the floor inside the car wet at all or do you get a funky smell with a mist on your windshield when you put the defroster on? Try to borrow a coolant pressure tester and test your radiator cap and the system itself, it could just be your cap gasket is bad and its loosing a little coolant from around the seal each time, there is also strips you can buy to test the coolant for hydrocarbons from a popped headgasket (it changes color). 1L per month is a slow leak but there should be evidence of it somewhere. If this coincides with the thermostat change it COULD be just an air pocket came out over time and now you noticed it. Let us know :)