[mjohnson]

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I have been getting the 82 interstate ready for the spring. I changed the coolant and the cap. Now I have the strangest problem. When warming up the engine it leaks a cup or so of coolant. After it warms up it stops? I searched the forum and someone said the small tube that connects to the neck of the radiator could be faulty. I removed the end that connects to the overflow bottle and blew into it. I could hear air escaping thru the cap - is that normal? The rubber seals on the cap appear -both the part that sits deep onto the recessed part of the neck and the rubber that sits on the top of the neck.

I am afraid of putting everything back together until I get this resolved. HELP - the weather is perfect for a ride.



Mike

 

[Goldwinger1984]

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Have you pressure tested the overflow tank itself to check for leaks?

Take your cap to a service station and have it tested to see if it's OK.

Vic

 

[Goldwinger1984]

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I should also add to make sure the seat for the cap is clean and straigth. Sometimes a piece of rubber from an old cap can get bonded to this seat and it will cause any new cap to leak.

Vic

 

[exavid]

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Bet number 1: You don't have the radiator cap all the way on!

It sounds like the expanding coolantis going overboard instead of into the coolant bottle. You shouldn't be able to blow air back up the overflow hose. You have a bad radiator cap or some crud under the upper seal. There are three seals in the radiator cap, the middle one is the middle sized one with a spring behind it that opens when the expanding fluid forces it up at 7psi or whatever that cap is rated at. The lowest seal is the little valve in the center of the aforementioned valve, this one is pushed open by atmospheric pressure when the coolant contracts during cooling and allows over flow to be sucked back in from the bottle. The third seal is the gasket just under the cap that seals off the top of the radiator neck. This one should always be tightly sealed as long as the cap is on the rad. Since you can blow air back up the tube and the only way air can get out is either the hose, it's connection or the upper seal isn't sealing. Make sure the cap is on properly. Try cleaning the gasket and radiator top. If you can still blow air through replace the cap.

 

[dean_3326]

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mjohnson wrote:

I have been getting the 82 interstate ready for the spring. I changed the coolant and the cap. Now I have the strangest problem. When warming up the engine it leaks a cup or so of coolant. After it warms up it stops? I searched the forum and someone said the small tube that connects to the neck of the radiator could be faulty. I removed the end that connects to the overflow bottle and blew into it. I could hear air escaping thru the cap - is that normal? The rubber seals on the cap appear -both the part that sits deep onto the recessed part of the neck and the rubber that sits on the top of the neck.

I am afraid of putting everything back together until I get this resolved. HELP - the weather is perfect for a ride.



Mike

Mike ,

Paul is right,I was able to shine a flashlight under my bike to see the antifreeze was escaping out around the cap even though the rubber gaskets looked good.. I replaced the cap and gently cleaned the small deposits off the top of the radiator neck and it solved the problem, Good Luck.

dean_3326 :12red::12red::12red::12red::12red::12red:

 

[mjohnson]

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I appreciate all of your help . I got a new cap and had the same problem - went back to the "first new one "and as I secured it to the neck I blew into the overflow tube until I couldn't hear any air escaping. It worked! I have started and stopped the bike several timesafter it had warmed up and have seen the fluid moving into the overflow tank - so far no problems. I did all the things suggested - cleaned the rim etc. To be honest I do not know why ittook so much fiddling with to get it to set - but it is on and holding its fluid :clapper:

 

[exavid]

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Part of the problem is the difficulty of getting to the cap in the first place. I have some experience with this too. I managed to punch a hole in the thin metal on top of the original cap on my 1200. I got a NAPA replacement, put it on and it leaked. I figured i'd gotten it on wrong because it had ears on it which made it even harder to put on. So I cut out a piece of thin brass, peeled off the old glued on top from the old cap and sweat soldered the new brass top on, painted the whole mess black again and voila, no leaks. The SEI had a lot of cables in the vicinity of the cap so the 'eared' type cab was just about impossible to get on all the way. Gotta get them caps twisted all the way to the stop!