stickershock
4/27/2008 5:26:52 PM
Just finished replacing my antifreeze today on the 04 Impala 3.8 K engine. I offer this post to those of you handy enough to do this and want to save a fair amount of money at a shop.
The problem with changing the antifreeze yourself is that it can be messy. Also, finding the radiator petcock to drain it is hard to get on my car and harder to turn if you are on your back under the car. So I gave up trying to drain the radiator. The system is a 3 gallon one so have a 5 gallon bucket ready to have a hose empty out the backflush.
I used a Prestone backflush kit which is a ripoff, sort of. You only need the two hose clamps they give you and one tee of three and a backflow coupler. The splash deflector tube was a joke and didn't work with my radiator. I installed the tee on the upper heater hose near the firewall. The hose was very tough and a knive did not work. I used some very sharp kitchen scissors. (by the way, the instructions on the Prestone kit were based on rear wheel drive cars obviously, because the pictures show a early model engine, ie not front wheel drive like today. Prestone really ought to revise its graphics!).
I found a hose that would fit snug into the radiator cap opening and let the other end feed into the bucket. Putting a garden hose to the tee in the heater hose, I turned on the water and backflushed the engine when it got hot enough to open the thermostat. Two people are best to help turn the engine on or off as needed. So far, this was the "easy" part.
Now to put in the new antifreeze. You take off the garden hose at this point and screw the cap back on the tee at the heater hose. I used the undiluted antifreeze, not the 50/50 premixed you can buy today. But since my radiator was full of water now and could not be drained through the petcock easily, I took a shot at just running the engine a short while to drain the radiator that way. I was prepared to pour in 6 quarts of antifreeze into the radiator, but found I had to use almost 8 quarts of pure antifreeze to get the boilover protection to 268 degrees F. So I just started and stopped the engine a few times with the screw cap on the tee lose, but not completely removed from the tee. A wide plastic cup under the tee caught the trickle of water coming from it when the engine was running. Now I had room to add more antifreeze to the radiator. After letting the engine cool down a bit, I rechecked the fluid level and the level of boilover protection several times before I could stop adding antifreeze.
Then I took the car for a ride and stopping a few times to check for leakes, which there weren't. Finally, I took it on the highway for a while. Checking the heat guage, the engine temp never got over 200 degrees F during the entire drive or even when at idle at a stopsign (200 degrees is the halfway mark between Hot and Cold on my guage).
This whole proceedure could have been easier if I could have drained the radiator at the petcock, but instead it was messy and a bit awkward, but on the whole it saved me about $40-60 after buying the antifreeze and flush kit.
After all of this, maybe you would rather just pay to have the antifreeze changed at a shop?
