I own a impala 2003 and i would like to know how to change the thermostat on it.The motor is a 3.4 liters
Drain radiator. Remove upper rad hose from thermostat housing. Disconnect air intake hose from throttle body. Remove throttle body from upper intake manifold, disconnecting the 2 rubber hoses to the heater line. You may also need to disconnect the fuel line. Remove the exhaust crossover heat shield and loosen the crossover pipe from both exhaust manifolds but don't remove crossover completely. You should have access to the 2 thermostat housing bolts, remove upper bolt but just loosen the lower one about a half inch. Pull the housing out and up from the intake manifold to access the thermostat. Clean the mating surfaces with a gasket remover. replace thermostat, apply a light coating of rtv sealant to both sides of the new gasket. Replace thermostat housing with the gasket to the intake manifold. Apply some rtv to the bolt threads before reattaching housing. Tighten bolts snugly but do not over tighten. Tighten exhaust crossover and reattach the heat shield. Install throttle body attaching the 2 little hoses at the bottom, its a good time to replace these hoses and clamps. Depending on the condition of the throttle body gasket you may need to replace it also. Reconnect the fuel line (if disconnected) Reconnect air intake hose to throttle body. Reattach the upper rad hose to housing. Fill rad with coolant 50/50 mix with water (make sure to use the same type antifreeze that is in the system, they say you can mix green with red but I wouldn't recommend) Leave rad cap off start the car and let it warm up until you can see the coolant circulating and ad coolant as necessary until full. Now there is going to be some air in the system that you need to bleed out. There are 2 bleeders on this system, 1 is on the top of the thermostat housing, and the other is on the metal heater line on top of the water pump (the one that goes across the front of the engine and around under the throttle body that the two little hoses attach to) Bleed the one on the housing first (its the lower one) open it until fluid comes out then tighten it. Then move to the 1 on the heater line(above water pump) loosen it until fluid comes out the re-tighten. Fill recovery tank to fill line replace the rad cap and take it for a ride, watching the temp gage closely. If the temp goes higher than normal than there is probably more air in the system. you'll have to bleed it again.
This is a very labor intensive procedure and I do recommend buying or checking a service manual out from your local library. I've done these in the past and to be honest I just have the dealer do it now. A system flush and thermostat replacement was around $230 the last time I had it done, but it comes with a warranty. And you wont have to rent or buy a fuel line disconnect tool if you end up having to disconnect it. These are the hardest thermostats I've ever replaced.
Jun 09, 2010 |
2003 Chevrolet Impala