JSwann

I just bought an '03 Z06 w/ 90k on it from the original owner. I put 200 miles on it since then. Went to drive it the other day and as soon as the engine got up to temp it spiked to the red. Turned it off for a few minutes and turned back towards home. It spiked again but wasn't able to pull over and after about 30seconds it went back to normal - no blowoff mist or anything, I was hoping it was a faulty gage. Drove it 30miles the next day no problem. Swapped out the thermastat and now it's over heating every time - yes coolant tank is full. When the heat is on full blast it's blowing cool air as temp is spiking. Does this sound like the water pump is bad? Really poor timing on my end as I legit just bought it and it's almost time to put away for the winter, but I want to drive it before then!

gimp

That almost always means you have a coolant issue. I'd guess you have air trapped in the system. Did you properly bleed the coolant system?

JSwann

I'm just a "driveway mechanic," I definately didn't correctly purge the system correctly after the thermastat install which is why it almost immediately spiked to red. I don't understand how air would be in the system if it's a closed system? This means it is pulling air from somewehre which means I have a leak?

JSwann

unless the thermastat was the problem, i fixed that and now a proper purge will remedy air entered in system during my thermastat install?

Vetteman Jack

Moved to C5 Tech.

Simtech

I replaced the water pump on my 03 years ago and didn't do any special bleeding procedures and have had no problems. Make sure your fans are working and that you didn't suck up a bag. Also did you check the thermostat before you put it in could be bad out of the box.

Bill Curlee

If you loosen one of the fasteners on the FRONT STEAM PIPE CROSS OVER PIPE,,, any trapped air in the block will escape and the block will fill with coolant.. YES, the air can be trapped in the block and cause overheating issues. Best just to eliminate that as a source of the issue. Its easy and FREE!!

Warning.. DO NOT remove the fastener if the block is hot or pressurized as it will allow coolant to GUSH OUT and possibly burn /scald you!!! Just loosen it enough to allow air & coolant to weep out until you see all coolant. Once you see a steady flow of coolant, retighten the fastener.

BC

Velocity_Vette

^^^ Bill Curlee's method is what I would recommend as it's quick and easy to do. it's also one of the highest points of the cooling system, which means it will be the best point of alleviation. It obviously should be done cold as Bill also mentioned.

Individual's experience with any potential overheating after a fill up will vary. Some see no air enter the system and in some cases air has potential to enter the system. It's best if possible to have the car completely level when filling it up. If you had the nose of the car up in the air or similarly tilted you have a higher chance of air entering and being pushed along.

If you're still overheating after a system burp I would check system pressure. The surge tank cap is the most common culprit.

JSwann

Thanks guys! When I replaced the thermostat, the nose was pointing down hill on a decent grade. I believe the thermostat was suspect, so I replaced it and then introduced air into the system like suggested. I had a shop purge the system ($111) which I found to be a little steep. I've since put 400 miles on it without any issues!