Figured I would pass this along to everyone.
My 2004 GT1 developed a no heat condition and it was beginning to run a little warmer than normal. This was a result of my lack of knowledge of DexCool. About 2 weeks ago, I checked my coolant level and noticed it was low. I added some traditional Glycol based antifreeze. (Big Mistake). As everyone may or may not know, Dexcool can not be mixed with Glycol. The combination results in a thick black goo that clogs up passages and the heater core. I was shocked when I pulled the radiator cap to find that it was caked in thick black goo. The guts of the radiator were caked in the gunk as well. Upon seeing that I knew immediately why I had no heat. This is what I did to fix.
Supply's
2 old laundry machine supply hoses with the ends cut off. Leaving the hose connector on one end.
1/2 cup of powdered Cascade dishwasher soap
2 Liter Soda Bottle
Garden Hose with good water pressure.
New Thermostat Gasket.
Heater Core Unplugging
1. Open the drain in the radiator and let the coolant drain out.
2. Locate the 2 heater hoses and where they connect to the engine underneath the alternator.
2. Loose the clamps.
3. Remove the hoses from the nipples, using a long flat screwdriver to get in the gap. Pull gently and they will come right off.
4. Take the laundry hoses and insert the cut ends into the heater hoses. Put the clamps over the connection.
5. Attach the garden hose to the lower heater hose. This is the return hose.
6. Turn on the water and hold the supply hose and point it away from anything you don't want to cover in black goo.
7. Stand there and be amazed at all of the crap that comes out of the heater core.
8. Turn the water off
9. Put the garden hose on the supply line of the heater hose and reverse the water direction.
10. Observe black water coming out of the core.
11. Do this about 2-3 times until the water runs clear. (The core is still not completely unplugged yet)
12. Reassemble heater hoses onto engine and re-position clamps
Engine Flush and Radiator Flush ( 1st clean)
1. Remove thermostat housing and thermostat.
2. Insert garden hose into filler neck and turn on the water. This will flush the old coolant from the radiator as well as force the coolant out of the engine having it come out of the thermostat housing.
3. Allow it to run for about 5 min until the water runs clear.
4. Remove hose and re-assemble thermostat housing.
5. Empty Expansion tank of contents.
Dexcool sludge removal.
1. Close radiator drain valve
2. Take cascade and dump it into the 2 liter bottle.
3. Fill with hot water and shake well until detergent is dissolved.
4. Put solution into radiator
5. Fill expansion tank with water until radiator is full.
6. Start car and allow it to come up to temperature with heater on.
7. Run car for 15 minutes, keeping an eye on the temperature gauge. Straight water is not a great coolant and the engine will run warmer than usual.
8. Turn engine off and open up the drain valve
9. Allow the system to drain
10. Remove Thermostat housing and put the hose back in the filler neck and flush system again.
11. Flush Heater core again.
12. Once everything has been flushed with water. Reassemble core and thermostat housing.
13. Fill with water again and allow engine to come up to temp and run for 15 min again.
14. Turn engine off
15. Drain again
16. Flush Core and Engine again.
17. Reassemble heater hoses.
18. Close drain valve.
19. With thermostat housing still apart, fill the expansion tank with your choice of coolant. (I put Dexcool back into it)
20. Observe the thermostat housing watching the water be pushed out. It should begin to change color. Once the coolant reaches the level. Put the thermostat housing back on.
21. Top off radiator with coolant and put the cap back on.
22. Start Car and allow it come up to temp. Check for leaks and go for a test drive.
23. Once engine has cooled check coolant level and adjust as neccesary.
After doing all of this, I was able to get the sludge out of the cooling system. The use of the cascade was the trick. I stumbled across this method on another forum and gave it a shot. Since the cascade is designed to cut oily deposits. It cleaned up the sludge with no issues. Looking down into radiator prior was discouraging. After I ran the cascade through it, the radiator is now spotless (From what I can see). I can so longer see any sludge from the Tstat housing either.
The key is too flush everything very well, It felt like I used about 500 gallons of water when I was doing this. But it did work. I now have heat again and the needle has returned to it's normal position even when idling.
Originally Posted by matt5112
