second year in storage that leak starts at radiator hose clamp

[Roadster Guy]

This seems minor, but it has me a little puzzled.

Last year when I put my Vette into storage in my outbuilding, about two weeks later when it got really cold in December, I found a very small amount of coolant pooled underneath the rad. I could not figure out where it was comming from and I looked everywhere, but I thought it was a rad leak. As the roads were dry and salt free (no snow that December), I drove her over to the nearby GM Corvette Dealer (never been there before). Turned out it was just the top driver side hose clamp being loose right at the rad connection...and so they replaced the clamp and did a pressure check and everything was fine and that was that..and didn't even need to add coolant...no big deal, very small charge and I was relieved.

I checked under the car all spring, summer and fall and never a drip and coolant level unchanged.

So, a few days ago, which would be about 2 and a 1/2 months into storage I see a small amount of coolant pooled on the floor. I check the whole rad and hose areas and then the top driver side hose and just underneath the hose at the rad connection is some coolant. And the clamp is a little loose, so I give the screw a turn till it's snug and I guess that is that. The coolant appears to have stopped leaking.

So, same hose and clamp two years in a row. The hose is only a couple years old and the clamp is now new. So I am wondering, is it one of the following that caused this:

clamp loosened up with vibration during the driving season?
the sudden arrival of very cold temperature caused something to contract?
there could be grit between the hose and the rad pipe it attaches to?
the clamp was loose last year and was still not tightened enough by GM?
the Vette is jealous and acting up because I only got tickets to see Tom Petty in June for my daughter and I?

Anyone encountered this kind of thing before?
RG

 

[Toms007]

I'm betting on the last option....at least I'm jealous!

 

[Roadster Guy]

I'm betting on the last option....at least I'm jealous!

You are probably right.........I think it also heard me mention that our seats were just in front of the stage about 4 rows up.............:guitar
RG

 

[tonylong]

Ya gatta do a pressure test to see odd leaks. I had a leak that didn't show as coolant on the floor, just kept disappearing. A pressure test showed up the weird snaky heater input hose not visible without removing other stuff, but clearly the culprit by the pressure test.
good luck

 

[G Winter]

Sounds like you had replaced the hose before it started leaking. If you did I have found that after new hoses go through heat cycles the clamps have to be tightened. If you didn't drive it much after the hose install it just may have been time . After a few more heat cycles this summer tighten both ends while warm . Most likely after that you won't see it again

Glenn

 

[Roadster Guy]

Sounds like you had replaced the hose before it started leaking. If you did I have found that after new hoses go through heat cycles the clamps have to be tightened. If you didn't drive it much after the hose install it just may have been time . After a few more heat cycles this summer tighten both ends while warm . Most likely after that you won't see it again

Yes, I did replace it and did not drive it much afterwards so that is probably the case. I will tighten them up this summer when they are warm. Thanks,
RG

Glenn

Ya gatta do a pressure test to see odd leaks. I had a leak that didn't show as coolant on the floor, just kept disappearing. A pressure test showed up the weird snaky heater input hose not visible without removing other stuff, but clearly the culprit by the pressure test.
good luck

Your're right. I'm going to watch the underneath for leaks and the coolant level and make sure the clamps are tight while I drive in the spring and summer. If it is still a problem I will get a prressure test. The pressure test was fine last year after the clamp was tightened, so I'm hoping it's the clamp again. Thanks,
RG

 

[crowvet]

Your're right. I'm going to watch the underneath for leaks and the coolant level and make sure the clamps are tight while I drive in the spring and summer. If it is still a problem I will get a prressure test. The pressure test was fine last year after the clamp was tightened, so I'm hoping it's the clamp again. Thanks,
RG

Sometimes a pressure test will not show up this type of leak. The pressure in the system actually puts pressure against the clamp and seals it. You most likely have a newer hose that hasnt shrunk all the way, and a worm gear style clamp. Worm gear style clamps cannot compensate for shrinkage or contraction or expansion. You could switch to the newer style spring loaded clamps that self adjust

 

[Roadster Guy]

Sometimes a pressure test will not show up this type of leak. The pressure in the system actually puts pressure against the clamp and seals it. You most likely have a newer hose that hasnt shrunk all the way, and a worm gear style clamp. Worm gear style clamps cannot compensate for shrinkage or contraction or expansion. You could switch to the newer style spring loaded clamps that self adjust

Yes it is a newer hose and it is a worm gear style clamp. Good idea, I will switch it to a newer style spring loaded clamp.
thanks,
RG

 

[G Winter]

Sometimes a pressure test will not show up this type of leak. The pressure in the system actually puts pressure against the clamp and seals it. You most likely have a newer hose that hasnt shrunk all the way, and a worm gear style clamp. Worm gear style clamps cannot compensate for shrinkage or contraction or expansion. You could switch to the newer style spring loaded clamps that self adjust

Now that you mention the spring loaded clamps, I don't think I have ever seen those leak. Just never gave it a thought till you mentioned it. Thanks for the heads up.
The only thing about the spring clamps is in some places they can be a real pain to install or take off.

Glenn