I have an '05 Pontiac Gran Prix with a 3.8 liter engine. Now that the cold season has arrived I have been using the heater in the car. The problem was that the blower did not blow out very hot air. Well the first thing that you would think is a plugged heater core, right? The only way too unplug the heater core is too have the entire cooling system pressure flushed or purchace new core and install it for a large fee. I called around for the lowest cost business that would flush it for me. I discussed my problem with the lowest cost business- Express Lube and they said to bring it up and they will take a look at it and see if it would be the thing to do. I pulled the car in the shop and the mechanic explained to me that the 3.8 litre is notorious for blowing the head gasket while pressure flushing the coolant system. Upon inspection he advised me not to do the flush, instead he showed me a trick that did save me alot of money.
At the heater core there is an inlet and outlet rubber hose for coolant. The mechanic told me to swap the hoses around and make the inlet the outlet and visa/versa and to run it like that for a few days. I will be darned if it did'nt work!! So now my cars heater is flame thrower again and it was all done with no money spent. I must say THANK YOU to the guys at Hwy8 Express Lube!! I will be paying them for a few oil changes this winter when I get lazy...I mean lazier!! LOL