1996 LT1 Cooling System Refill

[jonn454]

First post. I'm pumped. You guys seem to know a thing or two about Corvettes.

I drained my cooling system and used compressed air to evacuate all fluid out of the system. My owner's manual says the capacity of the system is nearly 4 gallons, but I've only gotten back in about 2 1/2. Took it out for a ride, and it cools great. Stays around 185 with the a/c off. When I come to a stop, however, it quickly heats up. My fans are working properly and when they come on, it drops the temperature fairly quickly. It just seems like it didn't heat up this quickly at a stop before I changed the fluid. I just bought the car two weeks ago, and the fluid was really bad. Should I be concerned about any of this? I've checked after letting the car cool down, and I'm not able to get any more fluid in.

Thanks, I have another issue I'll post on another thread. I appreciate all responses and feel lucky to have found this forum.

 

[Hib Halverson]

If you only put in 2.5 gal to fill the system, either you didn't drain all the old coolant out--maybe you didn't drain the block--or (worse) you have a big air bubble in the system. Either way, you may want to check the coolant level again.

If the coolant was really ugly when you drained it and you didn't drain the block (by removing the knock sensors), I'd drain it again then fill with a second fresh charge of coolant. This might seem like a PIA but it won't be a pain is you avoid having to replace some costly cooling system components.

 

[jonn454]

I read from multiple sources that instead of taking the knock sensors off, another way of draining the entire system was to use a shop-vac on reverse flow and blow air into the system. When I did that, alot more fluid came out that was not flowing out before, suggesting to me that the trick worked in emptying fluid that was in the block and not coming out on its own. So, I feel like I probably got all the fluid out.

But, I do see your point in that if I had gotten all of it out, why wouldn't I be able to put it all back in. Also, I took the bleeder screw off, the highest one, and there was fluid all the way to the top there. Does that sound like a good indicator that there isn't a large air bubble in there, or not?

 

[Hib Halverson]

I think it is more likely the "shop vac" method is urban legend and less likely you have an air bubble.