I have finally completed a water pump replacement on a 2007 Mazda 6 3.0. I also replaced the heater hoses that goes to the lower part of the water pump and all the hoses and a t connector above the thermostat housing.
I read everywhere that you need to burp the air in the cooling system and I tried but I don’t think I did it long enough. I didn’t drained or flushed the coolant out but I am going to do it soon at Jiffys since I don’t have a way to work under the car as it is always parked in a slope.
I let the car warm up with heat and fan speed at full blast while squeezing the radiator hoses occasionally but other than a gurgling noise I didn’t see the coolant level drop. I also didn’t have any heat.
I drove the vehicle to O’Reilly’s the next day to get some coolant, the whole time the engine coolant temp according to the gauge and my phone’s OBD app was fine.
As soon as I got out of the parking lot the engine starts to overheat. I immediately stopped the vehicle to let it cool down. I popped the hood and heard a hissing noise and water coming out from what it seems to be the water pump area.
The coolant in the reservoir or (expansion tank I think it’s called?) was low. I opened the cap slowly, but the hissing stopped and the fumes comes up to the reservoir.
I added coolant till it stopped going low and drove again. Temp gauge was on cold and I also had the heat on but it was blowing cold air still. I couldn’t drive more than 20 seconds because it was overheating. Found the coolant was low again, there were leaks but no hissing this time. Again I let it cool.
I repeated this till I got come. I lived about 10 mins away from Oreilley’s. It took me about an eternity to get home like that. The tow truck driver never arrived.
A couple of blocks on my way home I had stopped twice and noticed the coolant was not going low as fast. I still didn’t have heat but I made it.
I took the Haynes manual and read that if there’s leak it might be because of loose hoses or the thermostat. Admittedly, I threw away most of the original clamp that were in the hoses and bought the ones that you have to tighten with a screwdriver. I was afraid of overtightening the hoses but I was also afraid it might be too loose.
The thermostat was also not replaced. The car lost heat before the water pump replacement but I thought it was because of the leaks and water pump.
The leak seems to be difficult to spot as it dries up pretty quick when the engine is hot. I also don’t want to take the whole thing apart if the problem is not the thermostat but it seems like it could be shucked. How do I go about testing these two things? I
Hope I don’t have anything more serious that that. There are no check engine lights and no fumes of any kind coming from the tailpipe.