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have you pulled your battery and had the overflow tank out to inspect?
what might be happening is your overflow hose from rad. neck that goes to the tank under the battery- at the radiator neck it may be ok for coolant to belch out and not leak but on cool down when the radiator tries to pull coolant back from the bottle it pulls air in. and this would only cause your overflow tank to fill up if you keep pulling radiator cap and topping off radiator. i don't remember if that hose was a push on to the nipple at radiator fill neck, if it was try putting a hose clamp on there and/or some rtv/sealant on the nipple.
when you pull the overflow tank look below it for signs of coolant.
nice place to measure coolant system pressure is at the throttle body bypass hose.
when filling the cooling system it helps to undo this 1/8" hose at throttle body to bleed air out, but you can also use a pressure/vacuum gauge on this hose for testing, and then lay the gauge on top of the engine. After shutting off hot engine, put vice grips onto the overflow hose to pinch it off and you should observe cooling system pressure drop from around +15 psi and go negative, and stay negative until you undo vice grips and coolant (or air) sucks back in from overflow tank
I pressure tested my cooling system and found no visible leaks.
If your tester stays on the neck and holds pressure without any help, it should be good enough for a normal cap.
Originally Posted by WS6wanted
I have 93k miles on the car, and I ripped out the ac on my car so weep hole should be clear to see. I will check that out, thanks for the advice man
Did you ever get a good look under the water pump pulley at the weep hole?
The coolant must be going somewhere... I would try this. Run the car through two or three heat and then cool-down cycles, but don't move the car! Leave it in the driveway/garage. Then, look for fluid.
When my water pump was weeping, I lost the fluid one drop at a time and never saw it anywhere, except for a very small amount that landed under my A/C compressor from the weephole. If you can recreate the change over time without moving the car, that might help you find something.
The radiator level never stays up at the neck, the radiator full line is usually always at the lower nipple on the radiator for the steam pipe from the top of the motor. That hot pressure usually keeps the fill level below the neck in the radiator
So if the neck is the problem, then it would have to be bad enough that coolant is escaping from that area rather than following the proper path of least resistance (which would be the overflow tube.) Do you see any evidence of that happening?
I think I do see evidense now that you mention it. I will keep my eye on that.
After shutting off hot engine, put vice grips onto the overflow hose to pinch it off and you should observe cooling system pressure drop from around +15 psi and go negative, and stay negative until you undo vice grips and coolant (or air) sucks back in from overflow tank
That is a great idea, I will try that since I already have a vacuum gauge. I took out the overflow bottle, hose and tank are good.
If your tester stays on the neck and holds pressure without any help, it should be good enough for a normal cap.
Tester leaked until i put a thick rubber washer between rad and tester rad cap.
Did you ever get a good look under the water pump pulley at the weep hole?
I will jack the car up and check the weep hole following your instructions wssix.
The radiator level never stays up at the neck, the radiator full line is usually always at the lower nipple on the radiator for the steam pipe from the top of the motor. That hot pressure usually keeps the fill level below the neck in the radiator
My coolant drops a little below that lower nipple.
I appreciate all of the advice RPM, 1 FMF, wssix and chrysler kid. Im sure I can figure out my problem with the above advice. I will come back with what I find out when I get tine to check the car out.
If coolant was leaking out from the cap you would see stains on the radiator, and you would hear the coolant gurgle when you turned the car off after a long trip.
If it goes low to that lower nipple, don't add more. Keep monitoring the level. If it dips way below that lower nipple then you know you have a leak
I was topping off my car every day to the neck and I noticed it would push coolant out of the weep hole under the pump. It was a sign my cooling system wasn't holding pressure, but once it pushed out that extra above the nipple it was fine
Mine ended up being a gasket for the water pump. You can see the old silver and black gasket on the top.right was torn. My old pump was fine, but I replaced it for obvious reasons
Again I'm not saying you have a leak, I've just noticed normal for my car on the stock radiator was just below the lower nipple.
I agree with 1 FMF that the problem may only be in one direction (lack of fluid coming back to the radiator during cool down), but *only* if you've not been continually topping it off while the overflow level stays the same. If you have been topping it off, and the overflow level isn't rising but the radiator level continues to drop, then the coolant is being lost somewhere (rather than a lack of return siphon only.)
Originally Posted by chrysler kid
The radiator level never stays up at the neck, the radiator full line is usually always at the lower nipple on the radiator for the steam pipe from the top of the motor. That hot pressure usually keeps the fill level below the neck in the radiator
Mine have always maintained a radiator level that was right up to the fill neck, all four of my LS1 radiators have been that way. When I take the cap off, the level is always right up to the ridge where the inner portion of the cap seals.
I fixed my problem! Cheap fix too. My car was leaking from inbetween the filler neck and rad cap.
I had a new gm rad cap and a new napa rad cap. I took the rad seal from the napa and moved it to the ac delco rad cap for a thicker seal between rad and rad cap. And it worked like a charm. Last 3 times I have checked my rad level, its been full right to the neck.
Thank you for everyone input, and the help. Im glad this problem is solved
07-12-2017, 02:05 PM
