I've sprung an unusual leak!

Technical advice Q&A

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Ian Cooke
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#1 I've sprung an unusual leak!

Post by Ian Cooke » Fri Jun 12, 2020 7:48 pm

Hi All

I noticed a small amount of coolant had leaked out of the heater box and on investigation discovered that coolant was seeping out through the end panel of matrix. See photo:

Image

Any suggestions as to what would have caused this leak and any advice on if its possible to fix.

Thanks

Ian
Ian Cooke
1969 S2 FHC in Old English White

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cactusman
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#2 Re: I've sprung an unusual leak!

Post by cactusman » Fri Jun 12, 2020 8:41 pm

Hi. Sadly I suspect you will find the leak comes from the heater matrix exchanger within the heater box....essentially a small version of the car radiator (not a radiator at all but a best exchanger but that's another story). Probably uneconomic to repair the existing exchanger but they are available from the usual suppliers. You will need to drain a couple of pints of coolant out of the system (or drain the lot and renew), remove the end panel of the heater box, disconnect the hoses to the matrix (probably replace them too)...and then the matrix can be slid out. Sadly chances are the leak has caused rusting inside the heater box so a good time to clean up and paint in there while you await delivery of the new unit. Fitting is the reverse procedure....a not difficult task at all. :bigrin:
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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christopher storey
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#3 Re: I've sprung an unusual leak!

Post by christopher storey » Sat Jun 13, 2020 7:07 am

:yeahthat:

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288gto
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#4 Re: I've sprung an unusual leak!

Post by 288gto » Sat Jun 13, 2020 8:55 am

Perhaps order some new foam that goes round the matrix and stops it moving about in the box. Again available from the usual. I know Barratts do it as a kit. While you have the heater box apart check the foam seal on the internal flap. If this is damaged or missing you will get reduced air flow through the matrix.

Simon
Simon
1969 S2 OTS

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cactusman
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#5 Re: I've sprung an unusual leak!

Post by cactusman » Sat Jun 13, 2020 6:21 pm

Indeed....once you open the heater box you open a can of worms....you may wind up restoring the entire car again :bigrin: :bigrin: :bigrin:
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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tim wood
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#6 Re: I've sprung an unusual leak!

Post by tim wood » Sat Jun 13, 2020 6:50 pm

And if your brave enough give a close up check to the bulkhead pipes!
Series 1 FHC purchased 40 years ago. Courted my wife in it.
Series 1 2+2 when the kids were small now sold.
Series 1.5 OTS in opalescent maroon, Californian car. My retirement present.

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Topic author
Ian Cooke
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Location: Hampshire
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#7 Re: I've sprung an unusual leak!

Post by Ian Cooke » Tue Jun 16, 2020 7:25 am

Many thanks for the advice

I've removed the old heat exchanger which was in a pretty sorry state so I've ordered a new one from SNG. The inside of the heater box was in pretty good condition but I have nevertheless sent it off to be powdercoated. I had replaced the insulation around the exchanger a few years ago so that doesn't need replacing.

When draining some coolant I noticed that the radiator tap had a slight drip despite being in the fully off position. Any advice on how best to repair it?

Ian
Ian Cooke
1969 S2 FHC in Old English White

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MSM
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#8 Re: I've sprung an unusual leak!

Post by MSM » Tue Jun 16, 2020 9:25 am

Ian Cooke wrote:
Tue Jun 16, 2020 7:25 am


When draining some coolant I noticed that the radiator tap had a slight drip despite being in the fully off position. Any advice on how best to repair it?
Ian

I think if you remove the drain tap you will find that the part that you turn is a tapered plug held in place with a spring and washer and split pin. Dismantle it and you should be able to lap it in with fine emery paper and/or brasso and cure the leak that way.

I know you have only drained off a little coolant for your heater repair but you will have to bite the bullet!!! There is a slight chance that if you operate the tap open and shut a few times it might bed itself in but unlikely.

SNGB don't have a picture on their website but here is a link to a similar tap to show the construction.

https://www.moss-europe.co.uk/tap-radia ... soc=120533

HTH
Mike

S2 FHC

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