Radiator Fan Seal and Overflow fasteners

steve livesley, ,

A couple of inexpensive and easy jobs to tidy up the engine compartment back to original “spec”.The rad overflow pipe is supposed to be clipped to the inside of the rad mounting panel on to a cardboard spacer which i have not ever seen yet on other cars at shows.

Also there is supposed to be a foam seal strip between the rad and rad mounting panel to fill a 1″ gap. Never seen another MGB with one fitted yet ….. only a couple of quid and easy too fit. This reducers the air bypassing the rad and improving cooling efficiency.

An interesting article from the MGOC forum about the merits of the foam at

https://www.mgownersclub.co.uk/forum/mgb-technical/radiator-diaphragm-seal

An extract from this thread which explains it well posted 12 Mar 2014 at 13:27:23 UK time.
The response from Paul HUNT reads:-

When travelling forwards air is forced through the relatively large radiator grille. The area through the radiator is less than that, so air is pressurised in front of it. Any passages round the top, bottom or sides of the radiator will allow air to bypass it instead of going through it. The mechanical fan at least only gives a small fraction of the airflow and hence the cooling through the rad compared to when moving forwards, it will won’t even maintain the usual temp gauge reading at idle in warm weather.
I never had any cooling problems on mine without it either. But when I fitted one after many years, simply becauae it was supposed to have one, I was surprised how much it reduced the temp gauge reading in hot weather.

The stepped foam seal has the smaller box-section effectively under the edge of the diaphragm and behind the rad, the thicker section is what is visible on top of the rad and in front of the diaphragm. I had to reglue the two sections together before I fitted mine.
There should also be a rubber seal on top of the diaphragm to reduce losses between it and the bonnet

Also see Muenchausens article on the subject at …….. https://mgb.tips/2020/05/25/alternative-radiator-seal-from-muenchausens-garage/