Did a search and came up empty handed. My 2000 is about to turn 5, and I was thinking of replacing the coolant. I haven't been under it. Is there a petcock on the radiator? Any special procedures other than using Dexron II?

 

**The petcock is on the lower, passenger side of the radiator.**

Draining and Filling Cooling System

Caution
With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.

Important
If the procedure below is not followed a low or high coolant level condition and/or vehicle damage could result.

1) Park the vehicle on a level surface.
2) Remove the surge tank cap:
3)Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
4) Place a drain pan under the draincock.
5) Open the radiator draincock.
6) Allow the cooling system to drain completely.
7) Inspect the engine coolant for the following:
Discolored -- follow the flush procedure below.
Normal in appearance -- continue with the next step.

Notice
When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

Notice
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.


8) Close the radiator draincock. Tighten.
Tighten the radiator draincock to 2 N·m (18 lb in).

9) Fill the cooling system through the surge tank.
10) Fill the cooling system with a 50/50 mixture of DEX-COOL® coolant and deionized water.
11) Start the engine.
12) Allow the engine to idle for 1 minute.
13) Install surge tank cap.
14) Cycle the engine RPMs from idle to 3000 in 30 second intervals until the coolant temperature reaches 99°C (210°F).
15)Shut off the engine.
16) Remove the surge tank cap.
17) Start the engine.
18) Allow the engine to Idle for 1 minute. Fill the surge tank to 12.7 mm (0.5 in) above the COLD FULL mark on the surge tank.
19) Install the surge tank cap.
20) Cycle the engine RPMs from idle to 3000 in 30 second intervals until the coolant reaches 99°C (210°F).
21) Shut off the engine.
22) Remove the surge tank cap.
23) Top off the coolant as necessary, 12.7 mm (0.5 in) above FULL COLD mark on the surge tank.
24) Rinse away any excess coolant from the engine and the engine compartment.
25) Inspect the concentration of the engine coolant.
26) Install the surge tank cap.



Flush Procedure

Important
Do not use a chemical flush.

1) Block the drive wheels.
2) Place the transmission in Park or Neutral.
3) Engage the parking brake.
4) Run the engine until the thermostat opens.
5) Stop the engine.
6) Follow the drain and fill procedure using only clean drinkable water repeat if necessary until the fluid is nearly colorless. Refer to the drain and fill procedure.
7) Fill the cooling system. Refer to the drain and fill procedure.

 

Thanks Patches! Sounds pretty straight forward. My C4 had pellets in the system, I guess to clog small leaks etc. When the cap was removed it looked like brown mud was flowing through the system. I was really concerned until I learned about the "pellets" I'm glad the C5's don't use them!

 

Patches...Great info !!!!! I was planning on doing the same thing myself in near future as I am sure the Dexcool was never changed on my 97 C5. One question for you though Patches...do you know the amount in gallons that the cooling system holds? TIA!



Dave

 

12 Qts or 12.4 qts with MN6

 

12.6 quarts (11.9 liters)

 

Patches,

When I installed the SC I had to remove the radiator. How much of the coolant would have drained out? Would there have been some residual in the engine block? Can that fluid be drained out or is that why a flush is in order?

Thanks,

Matt

 

I've drained mine a few times by removing the rad, water pump and draining as much as possible but I never get all 12.6 quarts out. Some invariably remains in the block. Flushing is required to fully purge the old coolant.

 

Just curious...has anyone added a "T" connector to your hoses somewhere on the LS1 so you can attach a garden hose to flush system? I have done this on other engines like L99, LT1, L03s, thought that this might be a possibilty.



Dave

 

The problem you'll have is that you'll introduce tap water into the system and that will lead to corrosion. It's best to use distilled water and it costs about $1 a gallon. Get 5 gallons and flush with 3 gallons and use the rest for fill up.

 

Don't put tap water in your cooling system. Drinkable water will still corrode. Use distilled or reverse osmosis water only with the minerals removed.

 

Can the coolant change as described above be preformed when on ramps or should this be done on level ground?

 

drcoffee, thanks for the heads up about the tap water...I alway's run distilled water as well, just thought that flushing with the hose method might help in effectively flushing the system. Like you say distilled water doesn't cost much any way's so I will just buy enough distilled to do the job effectively.

I usually only run distilled water with 2 bottles of Waterwetter, but I was not driving in cold weather either and block/rad was completely drained too...amazing just how much your temps will drop doing this!

Have not changed coolant in the C5 yet, and I have decided to go with Dexcool, distilled water, and of course the 2 bottles of Waterwetter since whenever the roads are not salty or wet I want to be able to take it out for a drive every now and again until it just gets to bad where I can not...no wet roads or snow !!!

Since we are on this subject and I am sure this has been to death before, but what temp of T-stat does the consenus on here go with in the LS1? Of course with a reflash of the PCM concerning cooling fans temps lowered to turn on at lower temp.

Thanks for the reply's above and for those coming!



Dave

 

You'll get more out with the azz higher but the instructions call for the car to be level.

 

How do we feel about the GM stop leak tablets? I added one to my cooling system to stop a really small leak from the front of the motor (probably the water pump...) and it worked. Some say it ruins the radiator and heater core, some say GM made it for a reason and it's harmless. I'm probably going to get a 50/50 answer on this, but lets see anyway!!

 

Where would I buy de-ionized water? How do I know if it's discolored? My coolant looks orange and I'm not sure it it's ever been changed on my '01 w/ 41,xxx miles on it.

 

Just get Distilled Water from Walmart, like .50 cents a gallon. Distilled Water has no minerals and such that will harm your cooling system in as far as corrosion.

servohead...I know I had those tablets in my 95 Impala SS and it seemed like it left a lot of residue in the system, even looked like sludge when I flushed it. The coolant resivoir was completely filled with this "sludge", I even went as far as replaceing the resivoir as I could not get it all out of the resivoir. Personally I will not use the tablets on account of this, just my opinion on them.

January 2005 issue of Corvette has a great article about different variations of cooling mix, 50-50, distilled & Waterwetter, and such. Really brought a lot of questions I have had into perspective.



Dave

 

Actually I just found a website "GMtechline" and one of the 2003 issues covered the GM stopleak tablets in an effort to calm those who were worried about using them. The article explained the only caution to using them is in the right proportion. If one tablet doesn't stop the leak then you have to replace the component that is leakiing. The article also exclaimed that the crappy looking sludge in the coolant is nothing to worry about - it's just the remains of the tablet and it will harm nothing - and that's from GM. So, I think I'm ok. I put about 3/4 of a tablet in and it stopped my little leak from the front of the block (again, probably the water pump). I think now that the leak is plugged I'll flush the coolant next chance I get.