Engine and Transmission Tech

Did your heater used to work OK ?

Only ask as the MG heater box is not too efficient and you never seem to get a strong blow of air from it at the best of times.

Have you tried blocking the output vent on the passenger side. It increases the hampster output to the drivers footwell.

My bypass hose is routed straight to the heater matrix and then back to the rear of the Edelbrock manifold and gets warm air reasonably quickly.

FWIW, some years ago, I too had lower coolant temps when running in cooler weather until a few years ago when I changed the (180F) thermostat - I now have a nominal gauge reading of 184F whether it's 40F or 90F ambient temp.......so, for me, a t-stat change stabilized cooling system operation in hot or cold driving conditions..

Done, Graham. Haven't done any cold weather driving yet. The old 'stat tested fine on the stove. I really thought it would be stuck open.

Been reading and realized some of you guys are thinking the way I did after going from MGB to GM. If you run an MGB engine as hot as GM runs their engine, its by-by B engine. When I ran my GM engine the first time and it got over 195F , I shut it off. I then realized that I had installed a 195F thermostat in the engine. I went back to school on GM engine, on my Camaro 3.4 they don't even turn the fan "on" till the water temp. reaches about 215F and shut the fan "off" at 195F. GM likes it hot for emission control and economy.

In the winter I found that I need to let the thermostat open before I turn the heater blower "on" or it takes much longer for the engine temp. to reach operating 195F. On my setup the heater system is before the thermostat. I also cover the outside air intake and open the recirculate door inside the car.

If you have an oil cooler on the engine you likely need to cover it up in the winter. If you have a remote oil filer it my take longer to reach operating temp.

just my input

When I was having overheating trouble with my Mustang 5.0, I went through the cooling system from end-to-end. Boiled the radiator, replaced the heater core, new hoses, restrictors in the heater hoses, etc. I had purchased a jobber thermostat but the car's temp was erratic. I bought a RobertShaw replacement and it worked perfectly. Expensive, but it works the first time.

I would recommend a RS 195 degree part. 330-195