Coolant shooting out of overflow! HELP!!
Coolant shooting out of overflow! HELP!! Hey guys. I got a 99 ss. I've searched everywhere, and I just can't find anything on this fix. I just did a full rebuild on my LS1 with forged internals, heads, cam, stall, and all that good stuff. The car dynoed fine, no issues. As soon as I started driving it, coolant starting shooting out of the reservoir tank. So turned out the water pump was bad. I got a new OEM GM one, bled the system with the AIRLIFT vacuum kit (it held vacuum right at 27 psi). I'm still having issues with it. It warms up to temp fine, no overheating whatsoever. After I drive for a little bit, coolant starts coming out the overflow tank and gurgles a lot. The temps stayed right at 180-185 cruising so it's not overheating. I've tried every bleeding method, it's got new head gaskets because of the new heads, and the crossover/reservoir hoses are correct on the radiator. I've tried the radiator cap too, but it's the Stant metal one from Advance. Do I need the plastic OEM GM one instead? Cuz that used to be on the car before the work was done on it. Much help appreciated. Thanks!
Could it be the radiator cap? It's new but its a cheap metal one. Doesn't seem like it covers the overflow hole all the way, which would let air in. I'll get a GM one and try that.
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I would have to say....you need a new radiator cap. Maybe the new Stant cap is bad.......it happens.
Other than that.....only other thing that can cause the coolant to get pushed out the overflow cap....OTHER THAN AN OVERHEAT SITUATION......is a blown head gasket.
Time to get a pressure tester and see if the coolant system holds pressure.
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Well since my rebuilt motor has only like 100 miles on it with new heads, GM gaskets, and ARP bolts, I don't think it's a head gadket. When I used the airlift kit, the vacuum guage where the radiator cap usually is read 27 psi and never dropped. So wouldn't that mean the system holds pressure fine? Does that make the cap the issue? Ill order a GM one tomorrow, then post an update when I get it on.
Well since my rebuilt motor has only like 100 miles on it with new heads, GM gaskets, and ARP bolts, I don't think it's a head gadket. When I used the airlift kit, the vacuum guage where the radiator cap usually is read 27 psi and never dropped. So wouldn't that mean the system holds pressure fine? Does that make the cap the issue? Ill order a GM one tomorrow, then post an update when I get it on.
You say 27psi of vacuum.......you need to pressurize the system, not pull vacuum.
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Ok guys I got it figured out. I put a GM cap on it, and rebuked the system. And this whole time I've had my front air dam off for painting, well turns out I need that on........lol. That's what was causing the overflow when driving and not idling because there wasn't any airflow to the radiator. But she's all good now and just took her out to cruise night. Running great and pulling on crotch rockets! Lol
Ok guys I got it figured out. I put a GM cap on it, and rebuked the system. And this whole time I've had my front air dam off for painting, well turns out I need that on........lol. That's what was causing the overflow when driving and not idling because there wasn't any airflow to the radiator. But she's all good now and just took her out to cruise night. Running great and pulling on crotch rockets! Lol
Good to see ya got it figured out.....
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