I started replaceing my sons 2008 Aura radiator last night. What a pain, have to remove the bumper facia, wheel well liners, job isn't hard just takes time. I but new thermostat and hoses in as well. I like to put a little gasket sealant on the housing just as a precaution in case the thermostat seal some how leaks. My question is changing out the radiator you loose a little transmission fluid how much I don't know and this car does not have dip stick for the transmission. Does anyone know how much transmission fluid should be added?

Thanks, I didn’t want to do a full change, just changed oil last weekend and noticed the radiator leaking. This is my son’s car that he bought and drove from CA, didn’t realize there wasn’t a dip stick for the tranny. I guess I’ll try and just put a couple ounces in to make up for the rad replacement

That should be fine.

So changing radiator was a pain, but I leaned how to quickly remove the bumper and wheel well liners. Bough off amazon a kit with many different size push pins which helps to have on hand ($12.00 for a 240 piece kit). Anyways the radiator, thermastat, upper and lower hoses were replaced. Took awhile to get the coolant filled up takes 9.7 quarts for the 3.5 liter. But I may not of fixed the problem because this morning I went out and had a puddle of coolant on the passenger side, not sure if this was due to overfilling the reservoir or my water pump has a leak. Anyways after jacking and removing the wheel well cover and cleaning all the greasy gunk I could not find any leak, while on jacks I ran for a little but in hindsight maybe not long enough. Took for a drive and my reservoir after heating up was about an 1 1/2 inches above the cold fill line, running the car for about 20-30 minutes my gauge stayed between the quarter and half mark....is this normal? Also, could I have put too much coolant in and is it possibly just bleeding off excessive coolant? I don't mind changing the water pump but I could not see it leaking. When I did get home after driving and popped the hood looked like I saw coolant fly off the serpentine belt but isn't running out. Sorry for the long rant but beginning to get frustrated, was hoping to give the car back to my son but afraid that I may have to change out the pump.

Coolant slinging off the belt is a classic sign of a water pump leaking while running under pressure. There is a weep hole between the seal and the bearing to save the bearing for a little while after the seal starts to leak.

Could excessive fluid cause the pump to drain out through the weep hole? I'm not sure how many quarts I ended up filling the reservoir but might of had too much, where would the excess fluid go if that was the case.

If your system is overful the excess will push out past the cap. If you installed the OEM temperature thermostat you should be fine. Late model cars and trucks do not like cooler than stock thermostats, they will throw a trouble code if they do not reach normal operating temp in a preset time.