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Swapping Radiator for Dewitt’s, got a problem

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Old Aug 9, 2015 | 12:42 PM
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Default Swapping Radiator for Dewitt’s, got a problem

Changing it out was pretty easy, the problem I’m having is the inability to pulling a vacuum using UView Airlift Coolant kit. It will only pull down to about 4 on the gauge, if I close the valve it goes to zero very quickly.

It’s pretty obvious there is a leak, but all the hoses are on, reseated the clamps twice. The grommet I used fits the tank really snug. I have tightened it much more then I probably should have thinking that was the problem.

I’m considering pressuring the system using an air regulator to provide about 20psi from my compressor, with a soapy solution in a squirt bottle, might be the best way to find the leak.

Anyone have any ideas, or similar experience?

Mine is a 2015 Z06, but the service manuals are not available yet. I would think the 2014 Stingray would have the same coolant routing schematics and procedures being the same radiator is used.

If someone has the Service manual for their 2014 would you mind posting a pic of the hose routing if there is one?

Thanks in advance
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Old Aug 9, 2015 | 01:48 PM
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Originally Posted by Operations
Changing it out was pretty easy, the problem I’m having is the inability to pulling a vacuum using UView Airlift Coolant kit. It will only pull down to about 4 on the gauge, if I close the valve it goes to zero very quickly.

It’s pretty obvious there is a leak, but all the hoses are on, reseated the clamps twice. The grommet I used fits the tank really snug. I have tightened it much more then I probably should have thinking that was the problem.

I’m considering pressuring the system using an air regulator to provide about 20psi from my compressor, with a soapy solution in a squirt bottle, might be the best way to find the leak.

Anyone have any ideas, or similar experience?

Mine is a 2015 Z06, but the service manuals are not available yet. I would think the 2014 Stingray would have the same coolant routing schematics and procedures being the same radiator is used.

If someone has the Service manual for their 2014 would you mind posting a pic of the hose routing if there is one?

Thanks in advance
What's a "you view coolant kit"? Sounds like that's the issue.
I wouldn't put 20 psi to it either.
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Old Aug 9, 2015 | 02:04 PM
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its a way to fill the system you pull a vacuum and open a valve and it fills the entire coolant system, much better way to fill a system.
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Old Aug 9, 2015 | 04:10 PM
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You have a leak. Low pressure air and soapy water is a good way to find it. Keep the pressure well below the cap rating. More pressure really will not make it any easier to find. 10psi is plenty to find a small leak.
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Old Aug 9, 2015 | 04:24 PM
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Originally Posted by jcthorne
You have a leak. Low pressure air and soapy water is a good way to find it. Keep the pressure well below the cap rating. More pressure really will not make it any easier to find. 10psi is plenty to find a small leak.
I don't recall what my cap says, but I remember other cars labeled 25 or higher.
I think starting with 10 is a good idea, thanks for posting.
Now, if I could only find that dang regulator, any other time I'd be tripping over it.
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Old Aug 9, 2015 | 05:54 PM
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Found the problem!
The large lower hose was leaking, so I repositioned the clamp to no avail.

So I get my digital calipers out and begin measuring everything.
It turns out the new radiator hose neck's are smaller diameters then the original.

Here are the sizes
The large upper and lower OEM is 1.350"
The smaller lower clip-on OEM is .638
The smaller upper clip-on OEM is .375

(measurements are with in +- .005 difficulty getting calipers in there.)
The large upper and lower Dewitt's is 1.250" (0.100 smaller)
The smaller lower clip-on Dewitt's is .611 (0.020 smaller)
The smaller upper clip-on Dewitt's is .375 (same)


OEM neck



OEM Clip-on



DeWitt's neck



DeWitt's Clip-on

I will call Dewitt's tomorrow and see what they say.
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Old Aug 9, 2015 | 06:30 PM
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The problem we have is aluminum tubing is only available in certain sizes. You can get 1.0, 1.25" 1.5" & 1.75. With the molded plastic fittings they can dream up some odd ball sizes , like 1.35 and nothing is available to match perfectly so we use the closest thing. We've been doing this for ten years and thousands of radiators and that .100" had never been an issue. In fact, some have told us it makes it easier to get the hose back on. I don't recall anyone ever trying to pull a vacuum before so maybe the issue is only related to that method, I doubt the connection would actually leak fluid. You could dump the gm spring clamp and replace it with a good old fashion worm gear type. That will seal both vacuum and pressure.
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Old Aug 9, 2015 | 09:43 PM
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Originally Posted by Tom DeWitt
The problem we have is aluminum tubing is only available in certain sizes. You can get 1.0, 1.25" 1.5" & 1.75. With the molded plastic fittings they can dream up some odd ball sizes , like 1.35 and nothing is available to match perfectly so we use the closest thing. We've been doing this for ten years and thousands of radiators and that .100" had never been an issue. In fact, some have told us it makes it easier to get the hose back on. I don't recall anyone ever trying to pull a vacuum before so maybe the issue is only related to that method, I doubt the connection would actually leak fluid. You could dump the gm spring clamp and replace it with a good old fashion worm gear type. That will seal both vacuum and pressure.
Thanks for posting so quickly, I was hoping this would be the case.
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Old Aug 10, 2015 | 09:27 AM
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35mm aluminium tubing is available. The radiator hose connections are a metric size and 35mm is pretty common. (35mm is 1.37 inches)

Just trying to be helpful.
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Old Aug 10, 2015 | 11:33 AM
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Originally Posted by jcthorne
35mm aluminium tubing is available. The radiator hose connections are a metric size and 35mm is pretty common. (35mm is 1.37 inches)

Just trying to be helpful.
cost will have a lot to do with stuff.
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Old Aug 10, 2015 | 12:05 PM
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I looked up the CAD drawing I got from Paul Hammond of C&R Racing to look at their fitting sizes. It says : Custom Machine 1.35 in.


So it's certainly possible
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Old Aug 10, 2015 | 11:42 PM
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Originally Posted by descartesfool
I looked up the CAD drawing I got from Paul Hammond of C&R Racing to look at their fitting sizes. It says : Custom Machine 1.35 in.


So it's certainly possible
I'd like a copy of that drawing please.

tom@dewitts.com
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