O'Connor Classic Autos - Tech Talk - T-Series Fan Upgrade

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MG T-Series Fan Upgrade

We have made a simple modification to our MG TD which has had better than expected results; replaced the 2-piece metal fan with the one-piece, 7-blade MGB plastic fan, part number 434-340.

The job couldn’t be easier. Unbolt the existing fan, put small flat washers under the bolt heads, and use them to install the MGB fan. Leave the existing fan spacer in place. The holes and the bolt circle diameter in the MGB fan are slightly larger in diameter than the T fan. The stock bolts will fit against the sides of the holes in the MGB fan, centering it nicely.

Works just as easily on MG TCs and MG TFs, too.

The advantages include:

10 degrees Celsius reduction in the running temperature in hot weather, due to the fan being closer to the radiator and the blades much more efficiently shaped.
Much lighter weight, likely to reduce water pump shaft-to-pulley wear and increase bearing life.

Prior to this change, our TD, owned for 30 years, consistently ran engine temps in Celsius approximately equal to the ambient temperature in Fahrenheit on days above 65 degrees. On 100 degree days, the engine temp would typically be 95-100C. Now, in similar weather, we’re getting 85C max in mixed driving, including freeway speeds up to 65MPH.

Combine this with a coolant recovery bottle, which we have used for many years, and you may not need to add water at all during the season. We mount a square coolant recovery plastic reservoir, 4” wide, (available from the local parts house) next to the 8” Group 26 battery.