The images below are from one of my 'How To' posts.
It's not so much a fault, more of a quirk, and withing ten miles of picking up our Plus 4, when stuck in traffic at the Dartford Crossing, we had red hot air from the heater set cold - it was June.
Earlier Morgans have two sets of seals - one for each bonnet with a seal each side of the bonnet hinge. Someone on here, may be Gambalunga - has reverted to this arrangement. Eventually it became a single 'panel edge' lipped seal with a gap at the hinge.
Then it became a rough and ready sponge seal. On my current Plus 4 and my previous Plus 4 I've edged this seal both sides with high density neoprene, stuck with contact adhesive. For the top edge I found that leather worked best and together, these mods stiffen the seal no end. Around the hinge it needs to be more forgiving, as the bonnet hinge lips move in an arc across the seal.
The modifications, whichever you chose, make a huge difference.
Oh and extend the seal right back to the bulkhead, because there is a gap there.
From the archive.....................
The heater box seal.............
When we were stuck at the Dartford crossing, it was a hot day and all I could get from the heater vents was hot air. I modified the heater seal on Bumble, and have now done to same here.
This is how it comes, quite a soft sponge but lacking a seal centre around the bonnet hinges and at the bulkhead.
After adding neoprene edges and a leather top, plus some thick neoprene at the centre point it's much better.
