Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Plus 8 overheating

Using my 2003 plus8 daily, often in London traffic after a long haul up the M4, I concur with MOG16 and others. My temp gauge often reads 110C in traffic. If your cooling fan comes on and is blowing the right way, well and good. Mine goes off when temp shows 95 ish. Sometimes it'll cycle on and off frequently, which I consider normal. For peace of mind, I too fitted a bypass switch, which will keep temperature at about 95 (guage) in prolonged stop-start traffic, but the noise is distracting!
Regards, Phil

I have a 2003 Plus8. It doesn’t overheat BUT the fan does kick in regularly under lower airflow conditions. Mainly in summer. It is a Morgan aluminium rad not aftermarket ( Mulfab etc).
Using the gauge ( treated as rough estimate rather than actual temp), I get the following.
Winter
Shows 80deg but creeps up in slow traffic/on stop to 90. Very occasionally fan kicking in at about 98 if it goes up. Fan cuts out again at about 90. It cools back to normal (80).
Summer.
Shows about 88 but creeps up as in winter and fan reacts the same.
The only time I have had the gauge show more than 100 is when the fan fuse failed and the fan didn’t kick in. New fuse and ok after that.
So, no worries about cooling with glances at the gauge to spot over high readings.
Last time I changed coolant I back flushed the system.
I have rear bonnet extenders fitted for summer to help under bonnet air escape. It gets hot under there!
A test I did measured Incoming air temp.
Ambient air 15 deg. IAT went to 35 and rising slowly. The air is sucked in to the filter inlet in a non ideal way. No cool air feed but just under bonnet air. The exhaust manifold is not shielded.
I currently have a crude air feed to the lower rad area. A 63mm flexi pipe acting as a duct near the overrider to see if extra airflow can be found. No major influence, just a possible marginal one. It could be developed along with other airflow options ( reduced airflow leakage past the rad instead of through it) etc.

I concur with MOG615.
I have a 1980 +8 with a 3.9. Driven all over Europe and in 44C ambient temp. Survived with a header tank, Ali rad, bigger fan and over-ride switch. It's not boiled in 200+k miles. Given what you have done so far it needs to be an Ali Rad and override. I used a infra red temp gun and my gauge was running 10C over.
To check the fan is sucking. Turn the fan on and see if a handkerchief is sucked to the rad.

Evening. Being one of those pilot types. When I had an MG. I was amazed how many beautiful restorations that had their fans installed “ backwards” some just rotating the wrong way & some rotating correctly BUT their blade profiles reversed. Not saying this is the case here, but surprising. Well to me anyway.