Hence the design of rear bonnet catch extenders. Basically to increase where air could flow OUT of the under bonnet area. My 2002 Plus8 fan used to cut in a lot in summer. Basically the Morgan ali rad was only just capable of cooling the engine. Whilst driving the airflow was ok but it would climb quickly to the fan trigger temp in slower traffic.
I tried various fixes such as blocking air from bypassing the rad core, rear bonnet extenders. No badges in front of the grille. My last effort was testing extra scoops to direct air to the bottom area of the rad that was being shielded by it being below the airflow stream. It got hot under the bonnet! I got readings approaching 50 deg during some tests with incoming air temp to the enging hitting 35deg+ at 20 deg ambient. My Autel maxiscan enabled live running monitoring so a handy tool.
I monitored the temp gauge.
Summer......got to 80deg easily then steadied at about 85deg. No fan running
At 95deg the fan kicked in and temps returned to my car's "normal".
Winter......temp stayed at 80-85deg and rarer for the fan to kick in.
My mods did seem to help in a SMALL way by reducing the fan frequency a bit.
The car didn't overheat as the fan worked. Noisy but ok. It did overheat when the fan failed ( blown fuse) and stuck in traffic.
The bottom line was that the rad needed an increase in rad capacity as it seemed at it's limit and no spare capacity.
If I'd kept the car I would be looking at a fan manual switch plus trying a different temp switch. My aim was to reduce the fan frequency without compromising the overall temperature, i.e desensitize the system. Probably a new rad as the ultimate fix.
Years ago I had a car with a louvte that you could use to block off some rad area for winter.
Exactly my experience in the 94 +8 as our summers are warm in the mid 30sC with steep mountain passes to contend with. I have a manual fan switch which I use to activate the fan when climbing from 7000 to 11000 ft above sea level and in slower traffic at lower altitudes, going downhill does not require the fan.
