Holy crap!? - Disappearing coolant mystery!
09-18-2012, 10:02 PM
#21
TECH Senior Member
The Stant radiator caps have the vacuum valve...
( otherwise the coolant in the overflow bottle would not get back into the cooling system as it cools down, and you would see the radiator hoses pucker up )
( otherwise the coolant in the overflow bottle would not get back into the cooling system as it cools down, and you would see the radiator hoses pucker up )
09-18-2012, 10:30 PM
#22
I had a similar problem. The radiator cap wasnt sealing properly. I ended up bending the tabs inside it slightly to add a little more sealing pressure. Worked great and cost nothing.
09-19-2012, 08:09 PM
#23
Well I'm about to throw in the towel... I pressure tested the cooling system and it is not holding pressure. Looses about 1 PSI every 3 minutes. Got home and let the car idle with the cap off... steady bubbles. Still no smoke out the exhaust. Could this be anything other than the head gasket?
09-19-2012, 08:30 PM
#24
pull the plugs and do the coolant pressure test again is my thought...
had a lt1 in the other day that destroyed the head gasket/crack... but untill the plugs were pulled and we went to do a compression test did it actually show any signs of a bad head gasket other than low coolant...
the plugs will help keep the motor pressurized to resist the coolant leaking into the cylinders...
at least thats how i see it in my head...
perhaps read the plugs and see if there is a coolant stain or definate sign of water burning
had a lt1 in the other day that destroyed the head gasket/crack... but untill the plugs were pulled and we went to do a compression test did it actually show any signs of a bad head gasket other than low coolant...
the plugs will help keep the motor pressurized to resist the coolant leaking into the cylinders...
at least thats how i see it in my head...
perhaps read the plugs and see if there is a coolant stain or definate sign of water burning
09-19-2012, 11:12 PM
#25
I'm seeing a good excuse to buy a new expensive tool - a mechanic's borescope. (You might also be able to rent one.)
With a borescope, you can pressure test the system, remove the plugs, and then look in to the cylinders to see if there is any coolant pooling.
With a borescope, you can pressure test the system, remove the plugs, and then look in to the cylinders to see if there is any coolant pooling.
09-20-2012, 02:08 AM
#26
Teching In
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Vehicle - 98 SS - Mods in sig.
So I'm loosing about a 1/5 liter of coolant every 100 miles or so. Been happening for about a month. I opened the radiator cap and idled it for about 20 minutes last night and I saw some bubbles after the thermostat opened. I suspected the head gastket blew at a coolant passage as there are no puddles under the car.
However there is no smoke coming from the exhaust and no coolant smell anywhere inside or out. The car does not overheat, misfire or drive poorly in any way. All the plugs look identical and are dry (none are steamed). No trouble codes.
I just performed a compression check and here are the results...
Cyl 1 - 180
Cyl 2 - 180
Cyl 3 - 185
Cyl 4 - 180
Cyl 5 - 188
Cyl 6 - 185
Cyl 7 - 185
Cyl 8 - 180
I will mention that I did the waterpump and thermostat a few months ago. I installed a new rad cap and nothing improved. I did a pressure test at 18lbs and it slowly looses pressure. Like 1 lb per hour but then holds pressure after it dropps a couple pounds
I almost feel like the coolant is escaping to the expansion tank and not getting drawn back thru to the radiator. Figured the cap would fix that.
Gimme some ideas guys.
So I'm loosing about a 1/5 liter of coolant every 100 miles or so. Been happening for about a month. I opened the radiator cap and idled it for about 20 minutes last night and I saw some bubbles after the thermostat opened. I suspected the head gastket blew at a coolant passage as there are no puddles under the car.
However there is no smoke coming from the exhaust and no coolant smell anywhere inside or out. The car does not overheat, misfire or drive poorly in any way. All the plugs look identical and are dry (none are steamed). No trouble codes.
I just performed a compression check and here are the results...
Cyl 1 - 180
Cyl 2 - 180
Cyl 3 - 185
Cyl 4 - 180
Cyl 5 - 188
Cyl 6 - 185
Cyl 7 - 185
Cyl 8 - 180
I will mention that I did the waterpump and thermostat a few months ago. I installed a new rad cap and nothing improved. I did a pressure test at 18lbs and it slowly looses pressure. Like 1 lb per hour but then holds pressure after it dropps a couple pounds
I almost feel like the coolant is escaping to the expansion tank and not getting drawn back thru to the radiator. Figured the cap would fix that.
Gimme some ideas guys.
09-21-2012, 07:50 AM
#27
There's a small metel tube going inside the overflow. Mine was ate up with holes in it. So when the radiator overflowed it was only sucking air back into the radiator when cooling. Stump me too for a while. Just pull up the battery. And yank the tube out. There hard to find. Just seal it somehow. I used epoxy. No more checking coolant. Just oil haha
09-21-2012, 02:08 PM
#28
There's a small metel tube going inside the overflow. Mine was ate up with holes in it. So when the radiator overflowed it was only sucking air back into the radiator when cooling. Stump me too for a while. Just pull up the battery. And yank the tube out. There hard to find. Just seal it somehow. I used epoxy. No more checking coolant. Just oil haha
