09 SS Overheated - What now?
06-08-2017, 09:32 PM
#21
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I'm tending to agree with don also. Cylinder #1 is a little low compression, and also has the discolored plug. Just because your oil and coolant haven't mixed, you may still have a tiny head gasket leak. Coolant into the combustion chamber, but not into the crankcase. Good news for your rings.
Your slight loss of coolant in the recovery tank speaks to this also.
Hopefully the leakdown test will be conclusive. My compression problem was gunk buildup on the intake valves. cylinders 1-3 had 2-4% leakage, and cylinder 4 had 23% leakage(crankcase and intake, loudest from crankcase). After shell blasting, cylinders 1-3 have 2% leakage and cylinder 4 has 5-6% leakage (crankcase).
Your slight loss of coolant in the recovery tank speaks to this also.
Hopefully the leakdown test will be conclusive. My compression problem was gunk buildup on the intake valves. cylinders 1-3 had 2-4% leakage, and cylinder 4 had 23% leakage(crankcase and intake, loudest from crankcase). After shell blasting, cylinders 1-3 have 2% leakage and cylinder 4 has 5-6% leakage (crankcase).
If the head gasket leak is between a coolant passage and the cylinder shouldn't the car be puking up coolant or at least bubbling as combustion gasses enter the coolant and cause a volume expansion?
Thanks for the help guys. I'm not trying to be difficult, I just want to explore the possibilities before committing to some very spendy repairs.
Last edited by 87ninefiveone; 06-09-2017 at 05:42 AM.
06-09-2017, 01:15 AM
#22
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If the head gasket leak is between a coolant passage and the cylinder shouldn't the car be puking up coolant or at least bubbling as combustion gasses enter the coolant and cause a volume expansion?
Thanks for the help guys. I'm not trying to be difficult, I just want to explore the possibilities before committing to some very spendy repairs.
Thanks for the help guys. I'm not trying to be difficult, I just want to explore the possibilities before committing to some very spendy repairs.
06-09-2017, 08:09 AM
#23
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I bet if you open the hood in the morning, with a stone cold engine, you will find the upper radiator hose has collapsed. That is because exhaust gasses in the coolant. Doesn't always happen.
06-09-2017, 07:22 PM
#25
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Donbrew, I've not seen sings of the upper radiator hose collapsing, but I'll continue to keep an eye on it. I'm not sure this could even happen though as the coolant recovery tank has a hole in the cap and on the jug itself. An open system should not form a vacuum.
Another few bits of info, manifold vacuum is reading a steady 19.2 in Hg at idle after warm up. The reading doesnt wander more than a tenth or two. And my Aeroforce gauge is reporting occasional misfires when I drive, about one every couple of minutes. I can't nail down the cylinder through the gauge as it seems to think I have a six cylinder and every cylinder (including those that don't exist) report occasional misfires. This is consistent with how the car acted before the high temp excursion, so that's good news. Still no DTCs as well.
I'm going to try and borrow a compressor from a friend and find a leakdown tester next week. I'll try and pull plug one again Sunday after some more driving to check for rust again.
Thanks again for the help guys!
06-09-2017, 08:32 PM
#26
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If you end up with a harbor freight, or other discount leakdown tester, see my post #6 in this how-to for instruction on how to get it to work properly. Looking forward to seeing what you discover!!
https://www.chevyhhr.net/forums/how-...-engine-56053/
https://www.chevyhhr.net/forums/how-...-engine-56053/
06-10-2017, 08:21 AM
#27
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Well, I must have been hallucinating when I looked at my upper hose every day for 6 months. It must create a vacuum if it is going to draw coolant from the bottle. Gas acts different from coolant. Are you forgetting about the "pressure cap" 15PSI running, how could that happen in an open system?
You don't need a compressor, a hand pump would work.
You could even do a long pressure test on the coolant.
You don't need a compressor, a hand pump would work.
You could even do a long pressure test on the coolant.
06-10-2017, 06:59 PM
#28
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Well, I must have been hallucinating when I looked at my upper hose every day for 6 months. It must create a vacuum if it is going to draw coolant from the bottle. Gas acts different from coolant. Are you forgetting about the "pressure cap" 15PSI running, how could that happen in an open system?
You don't need a compressor, a hand pump would work.
You could even do a long pressure test on the coolant.
You don't need a compressor, a hand pump would work.
You could even do a long pressure test on the coolant.
Maybe the reservoir on your car is designed differently and it isn't open to atmosphere, or maybe something else was going on, but with a properly functioning open cooling system the pressure/vac should be minimal up to the coolant's boiling point and hoses shouldn't collapse.
I agree that the system does run under slight positive pressure which is generated by the water pump and thermal expansion of the fluid. But, the whole purpose of the recovery tank is to relieve that pressure differential by allowing for volume changes in the system. The radiator cap is a failsafe to prevent the system from building up more than 15 psi of pressure in the event that the coolant boils and pressure can't be relieved quickly enough via the expansion tank.
I don't agree with your comment about system vacuum. As you noted, when the car cools it will draw a slight vac and suck in coolant from the overflow. However, in an open system this vacuum is relieved as air is drawn into the reservoir to replace the coolant. In that situation hoses should never collapse unless something else is going on and vacuum is allowed to build with no way to be relieved (i.e. you're cooling system is no longer an open design.)
06-10-2017, 08:24 PM
#30
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Not at all. The cooling system still needs to be burped.
I'm just saying that the system's pressure is near atmospheric unless you're boiling coolant which means any positive or negative pressure it builds is relieved by the expansion tank.
I'm just saying that the system's pressure is near atmospheric unless you're boiling coolant which means any positive or negative pressure it builds is relieved by the expansion tank.