Oem viscouse cooling fans "v" electric fans ? - post - nat.

Hi Guys, Be interesting to see what other member's views are on this subject.

The information i have gathered is as follows:

VISCOUSE FAN. (A FEATHERING FAN). OEM FITTED.

1. They produce 35% more volume of cooling air when the expandable clutch locks on, circa 95 deg. C.

2. When not in use, (feathering), they use very little torque to drive them.

3. When not in use they have 20% less pressure drop to incomming cooling air against the electric fans.

4. They have very good longevity but weigh 50% more than an electric fan unit.

5. When the engine stops there is no thermostatic timed cooling.

ELECTRIC THERMOSTATIC FANS.

1. These are fitted to most current cars as they are half the cost for the OEM's to fit.

2. They have the advantage of maintaining cooling air flow when the engine has stopped.

3. They only weigh half as much as a viscouse fan.

4. They make more space between the radiator and the front of the engine.

5. They have difficulties not working after long periods where the fan stat did not operate or the fan bearings were corroded and seized due to their exposed weather location on the vehicle. In some instances causing expensive overheating damage.

MY EXPERIENCE OF WHY I INVESTIGATED THIS SITUATION:

1. Post my NAT conversion and the inherent increase of under bonnet temperatures, (exhaust and down pipe etc), i went through 3 batteries in 18 months, they were top quality Bosch. I researched the location of the battery and consequent "The life expectancy" of batteries "V" ambient temperature locations, i took some measurements and the NA readings which i took from my Grandson's NA were 30% higher on my NAT.

2. The down pipe, the turbo and the new exhaust manifold overheated the brake master cylinder unit and a warning light came on.

3. The engine starter relay, which has a built in thermal cut out stopped the engine from cranking.

4. The fiber noise attenuating material was melting on the bulk head.

NB: All the items listed have now been baffeld with aluminum and ceramic board insulation, there are also air vents in the bonnet above the items which overheated.

MY CONCLUSION:

1. The OEM cooling fans are the best.

2. Baffling items that overheat is the most simple way to protect them as well as allowing air movement out of the bonnet above them.

3. I cannot see any advantages in the electric fan units.

4. Time reveals the overheat problems due to fatigue, so you think all is ok until the component fails. I had no issues for the first 18 months after the NAT Conversion.

So. what do you think? Herbie.

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