Cap is leaking again
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From: weems va
Cap is leaking again
I replaced my radiator cap with a new GM cap. Old one was leaking not bad but anoying. Car never runs hot fans come on at 228. When i make my daily 11 mile run into work it runs a steady 201-203 Radiator has been cleaned not leaking anywhere else just from cap! Any ideas? Thanks Dave
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From: SANTA CRUZ CA
Assuming your vette is a '93, check the fill neck for a crack(s), as suggested by the previous poster. The original cap requires considerable torque to loosen and tighten, and the old brass can split, as shown in my photo marked by the black lines.
Just by chance, I found the cracks in my neck as I had to feel for the crack by finger nail.
The temps posted seem high, as I would expect them to be closer to 195-200.
Is the surge tank 'full' when the engine is cold?
If not, there is a leak in your 'closed system', possibly a crack in the fill neck, allowing air to enter the cooling system
which would negate any siphon from the overflow bottle back to the surge tank during cool-down.
The new caps (most are made by STANT) are for both 'open' and 'closed' systems, and do not require excessive force to remove, and attach. My cap was made by STANT and packaged in an ACDelco box.
Just by chance, I found the cracks in my neck as I had to feel for the crack by finger nail.
The temps posted seem high, as I would expect them to be closer to 195-200.
Is the surge tank 'full' when the engine is cold?
If not, there is a leak in your 'closed system', possibly a crack in the fill neck, allowing air to enter the cooling system
which would negate any siphon from the overflow bottle back to the surge tank during cool-down.
The new caps (most are made by STANT) are for both 'open' and 'closed' systems, and do not require excessive force to remove, and attach. My cap was made by STANT and packaged in an ACDelco box.
Last edited by don hall; Jul 30, 2013 at 08:26 PM.
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Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
It's your choice, but I would recommend replacing the surge tank.
The tank is subject to 235 deg heat, 15# pressure, and severe torque removing/attaching the cap. New tank comes with low-coolant sensor installed.
The part# is 10157994 and priced at: $44.50 + $12.95 shipping
from GMPartsDirect (enter the part # in the space provided).
http://www.gmpartsdirect.com/
The tank is subject to 235 deg heat, 15# pressure, and severe torque removing/attaching the cap. New tank comes with low-coolant sensor installed.
The part# is 10157994 and priced at: $44.50 + $12.95 shipping
from GMPartsDirect (enter the part # in the space provided).
http://www.gmpartsdirect.com/
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From: SANTA CRUZ CA
When the new tank is installed, I think you will see a drop in operating temps as the siphon will now occur during cool-down replenishing expanded coolant from the overflow bottle.
With a break in the cooling system, I would expect your coolant level was low, unless you were filling the tank each time you drove.
Do not be concerned about air in the system with the new tank.
The LT1 is self-bleeding. Just check the coolant level after the engine has cooled down after your first drive....... add coolant, if necessary.
With a break in the cooling system, I would expect your coolant level was low, unless you were filling the tank each time you drove.
Do not be concerned about air in the system with the new tank.
The LT1 is self-bleeding. Just check the coolant level after the engine has cooled down after your first drive....... add coolant, if necessary.
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From: weems va
Yeah i was losing a little coolant but not too bad.I had just added it last night when i found(i hope i found the leak) Didnt use car today and long week end off with my boat so it will sit a few days. Dave
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From: SANTA CRUZ CA
If your coolant level wasn't very low, you might check the condition of the air dam under the nose of the vette, and for any debris in front of the radiator that may be restricting air flow. Would like to see the temps around 195.
I'm aware that you posted the radiator had been cleaned....... just checking to see if you meant debris.
I'm aware that you posted the radiator had been cleaned....... just checking to see if you meant debris.
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From: weems va
I pulled radiator cover off when i got car last november? Now that was a pain in the ***. But it was needed badly. Since then i have kept after it with a air gun. I put a 3 ft long brass tube/pipe on the nozzel to reach where no man has been before! Living in farm country with the farmers and high way dept leaving who knows what on the road finds its way up and in the radiator scoop. Its funny with my pick up i dont hesitate to go over debri or dead critters,but no more!
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Joined: Aug 2002
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From: SANTA CRUZ CA
I pulled radiator cover off when i got car last november? Now that was a pain in the ***. But it was needed badly. Since then i have kept after it with a air gun. I put a 3 ft long brass tube/pipe on the nozzel to reach where no man has been before! Living in farm country with the farmers and high way dept leaving who knows what on the road finds its way up and in the radiator scoop. Its funny with my pick up i dont hesitate to go over debri or dead critters,but no more!
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From: SANTA CRUZ CA
Dave, any idea when the coolant was last changed, if ever?
My temps dropped about 5 deg after a coolant change.......
doubt that it was ever changed before.
If you decide to flush the system, it is recommended to remove/replace the two knock sensor located in the bottom of the
block. It is not a technical job, just raising the vette, and dodging the coolant is a pain.
My temps dropped about 5 deg after a coolant change.......
doubt that it was ever changed before.
If you decide to flush the system, it is recommended to remove/replace the two knock sensor located in the bottom of the
block. It is not a technical job, just raising the vette, and dodging the coolant is a pain.
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From: weems va
Changed coolant last October or November when i cleaned radiator. I ordered a new tank. I had some good 2 part epoxy that i have used on my boat so i thought id give it a try while waiting for the new tank. Oh well it turns out there is a small crack almost the same as the picture in the brass neck. At least i was able to ride around some this week end. That sending unit in bottom of new tank,is that in my 93? I forgot to look yesterday. Dave
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From: SANTA CRUZ CA
Yes, the 'low coolant' light on the dash is triggered by the sending unit in the bottom of the surge tank.
About 3 screws, 2 hose clamps, 1 electrical connector (sensor) is all that is involved to replace the tank.
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From: weems va
New tank installed and no more leaks.What temp are you running Don? My run into work is 11 miles i get up to 198/201 and it holds there. In traffic or sitting at a long light it may hit 205. I guess i better re check the radiator. The only problem with living in the country is alot of grass and such on the back roads. Not to mention the deer!
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Joined: Aug 2002
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From: SANTA CRUZ CA
New tank installed and no more leaks.What temp are you running Don? My run into work is 11 miles i get up to 198/201 and it holds there. In traffic or sitting at a long light it may hit 205. I guess i better re check the radiator. The only problem with living in the country is alot of grass and such on the back roads. Not to mention the deer!
I drove my '93 ruby for 12 years, and it ran hotter (5+ deg) than my '92, even though they are the same cooling system.
Enjoy your repaired vette.....