J2571

I have 2001 Z06, I changed the coolant reservoir container and now it is running hotter than before. Previously it ran on 200 - 210 and now is running in 235 - 240. The history is as follows: Previous to change the coolant reservoir, I collected the coolant contained in the old reservoir and there was ~2 liters of coolant. I installed the new reservoir and prepared 2 liter of new coolant mixture. However, when I was adding the new coolant mixture almost 1 liter of the new coolant left. Then, it looks like less quantity of coolant was needed. I used the purge process described in the service manual by various times (run engine with reservoir un-capped then, capped and rev it to 3,000 then, turn off and repeat the process) but no additional coolant was needed to be added to the reservoir. Therefore, since almost 1 liter of coolant left and now it is running hotter, I desire to bleep the system to check if the issue is some air in the system.

I found other thread titled Overheating where the instructions to bleed the system were provided and satisfactory results were obtained but I can not see that instructions neither get the photos posted. My mechanical skills are not so strong. Putting grades to the mechanical skills, a mechanic with experience in Corvettes has a 10 and I have a 3 or 4. Then any help on the instructions to bleed the cooling system and any photo will help.

Notes: Radiator and fans are news (less than 4 months) and were working well. They were changed by skillful mechanic who knows Corvette's well. I observed that change the coolant reservoir should be an easy task then, I decided to do it myself.

3sACROWD

If I understand your description, you had to add only 1 liter to your expansion reservoir but drained 2 liters from the old one? Did your coolant level drop after cooling the engine?

Try turning on your heater when you attempt to burp it next time. That is likely where your volume differential is.

J2571

Hi!
Yes you are right and the coolant level never dropped. I will try your suggestion, turning on the heater.

aaronc7

Best advice I can give is, raise the front end of the car a bit if you can easily.... like drive up onto some ramps, or even some wood blocks would be better than nothing. This helps elevate the front of the engine so help air move the front and highest point of the cooling system and burp any air out.

Start the car with the coolant cap off, let it come up to operating temp. Heater on thing worked on older cars, I'm not 100 percent sure it applies to this car, but it certainly won't hurt.

As the car warms up my process is 1.) keep a close eye on the coolant temp gauge to make sure its not overheating 2.) touch and squeeze the coolant hoses, especially the large inlet and large outlet hose of the radiator. They will be cool to touch until the thermostat starts to open and the hot water in the engine blocks starts to flow thru the radiator etc. Once the thermostat is open and coolant is flowing in the system, the purpose of the hose squeezing is it push out any large air bubbles. This has fixed burping/overheating issues for me several times on different cars. 3.) every so often get back in the car and cycle the RPMs... I go between idle and around 2000-2500 rpm in about 30 second intervals

I keep doing this process until car has reached operating temp for some time and feel confident that the temp is stable and no air bubbles etc. Then I shut the car off, top off reservoir (get car flat first), then put the cap on. As you drive the car the next few times, the coolant level may go down a little bit.. no biggie, just top it off once or twice more and you're good to go. Don't remove the cap if you just parked the car and the water is hot.

J2571

Thanks you, I will do this weekend. I will post the results.

crf450x

A vacuum coolant fill tool is a great investment. You’ll never have to fool with this again.

Also, could someone please explain how turning the heat on changes anything? These cars don’t have a heater control valve do they?

J2571

Hi!
This past weekend, I raised the front of the car on a ramp, checked on the hoses connected to the throttle body and coolant was flowing out. Then, performed the 3-4 cycles of the following: with cold engine, un-cap the reservoir, idle rpm by 5 min., cap the reservoir and jump to 3,000 rpm by 5 min, idle rpm by 2-3 min, jump to 3,000 rpm, go back to idle, jump again to 3,000 rpm and turn off. Before the initiation of the last two cycle, I needed to add coolant mixture. At the end, the temp was good running at about 200.
Thanks you for the help.

ArtClassShank

I'm just guessing,

But turning on the heater will draw coolant through the heater core, pushing out any trapped air/coolant that might be in there.

Either way, I've followed the procedure 2 times and have bled the system perfectly both times. On jackstands on a slight uphill.

02VetteGA

I bought the Harbor Freight Maddox cooling system test and refill kit $80. I was able to get it down to -20 psi and following the directions filled the system with no issues. I also had air in my system and no other procedures worked. I went with a Napa 160 degree thermostat and on my 02 with oem water pump it's the whole housing vs some years just need the thermostat. I had the heater on high when I turned off car so also don't know if the heater core was flushed as well when I drained the system.

grinder11

Good info is timeless, but it might be better to start a new thread, as this one is almost 3 years old. Just sayin'

Cruss127

just bought Maddox system too, I know this is old but have you had good success with it? I’m going to start doing track days and want to make sure I have ALL the air out

ipuig

I've owned three C5 and never used such a device to purge the air out of the system after replacing the coolant. It is not necessary in my opinion.

Cruss127

normal purge procedure would suffice I suppose then. I was going to but this kit or a leak down tester. Guess il return this lol