- Joined
- Aug 9, 2022
- Messages
- 165
Recently I have found that the coolant level in my 3.6L Pentastar is always about 1/2"-3/4" low near the bottom of the radiator neck if I check it when the engine cools down after driving the vehicle. If I fill it back up until it touches the bottom of the radiator cap, the level goes back down to the same spot the next time I check it. It started doing this after I refilled the system the last time I serviced it, but I would be surprised if there is any residual air remaining because I used a vacuum filler followed up with a few cycles bleeding with a funnel.
I originally thought that there may be air getting pulled in from the end connections at the overflow tank hose during cooldown, but I found that the level also drops to this same spot immediately after pressure testing the cooling system with a cold engine. The coolant temps when running are stable between 203F-210F, and it has never overheated. I sprayed down all of the cooling sysem connections with soapy water, and used a borescope to inspect around the base of the oil cooler when I had it pressurized, but there is no evidence of any coolant leakage.
I am a bit puzzled because about an ounce of coolant will just seemingly disappear after each time I pressurize the system to 18 psi with the pressure tester. I can hear some gurgling as I release pressure from the tool, and the level will be near the bottom of the filler neck when I remove it (I noticed the level rise a little one time after letting it sit for a while after removing the tool). Is it possible there is an air pocket stuck deep in the system that gets compressed when I pressurize it making it seem like the level dropped at the radiator neck? I don't think it is leaking into a cylinder because the level drops this much even after a very short amount of time being pressurized < 2 minutes.. I see no evidence of coolant on the dipstick, and I was able to turn the engine over by hand after pressure testing it without hydrolocking.
I originally thought that there may be air getting pulled in from the end connections at the overflow tank hose during cooldown, but I found that the level also drops to this same spot immediately after pressure testing the cooling system with a cold engine. The coolant temps when running are stable between 203F-210F, and it has never overheated. I sprayed down all of the cooling sysem connections with soapy water, and used a borescope to inspect around the base of the oil cooler when I had it pressurized, but there is no evidence of any coolant leakage.
I am a bit puzzled because about an ounce of coolant will just seemingly disappear after each time I pressurize the system to 18 psi with the pressure tester. I can hear some gurgling as I release pressure from the tool, and the level will be near the bottom of the filler neck when I remove it (I noticed the level rise a little one time after letting it sit for a while after removing the tool). Is it possible there is an air pocket stuck deep in the system that gets compressed when I pressurize it making it seem like the level dropped at the radiator neck? I don't think it is leaking into a cylinder because the level drops this much even after a very short amount of time being pressurized < 2 minutes.. I see no evidence of coolant on the dipstick, and I was able to turn the engine over by hand after pressure testing it without hydrolocking.
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