Viscous Fan and Temperature, Tasmin 280

[micha]

Last week i recognized that my viscous-fan doesnt work properly. this means the viscous unit was blocked (bearing seized) which makes the fan run permantently. a few shots WD40 and the bearing was free again. after a while i recognized that the bearing had a lot of play...so i decided to replace the viscous-unit by a new one from my local ford-dealer around the corner. during the test-drive i was amazed that my engine was running much more powerful and the temperature stayed around 180 fahrenheit as before.

this weekend i had a longer trip and took the motorway. for the first 20 miles the temperature stayed as before but than started to climb-up slowly to 200 fahrenheit.

reducing the speed and it dropped down again to 180-190. but i couldnt go faster than 3200 revs.


so i think it was a bit a waste of money to invest in a new viscous-unit.

i know that the best would be to take it off and replace it by an electric fan, but i want to keep the car as original as it is.

.any idea what i can do?

[leorest]

Could it be that the air flow is now OK and that the coolant flow needs attention?

[micha]

this mean: radiator blocked by stains?

i forgot to tell: i have no shroud around the fan.. i dont know excatly if there should be one or not. most pictures of tasmin-cars dont show a shroud.

also interesting was that even with the higher temperature the radiator-filler cap doesnt open to release any pressure...(the cap is ok).

[jeff m]

A viscous fan isn't doing much once you are moving, it does most of it's work at when you are going slowly in traffic.
My viscous fan keeps my car's water temp well within safe operating range even in 90 degree heat at idle.

Switching to an electric fan will not solve your problem.

See water cooling thread, it's for a 350 but the theory is the same.
Pressure caps, pressure test cooling system. Flushing system may help, (back flush heater matrix while your there) Then thermostat last, as it's an unpleasant job on a 280.

[micha]

calculated again the temperatures: 200 fahrenheit is 93,3 degrees celsius.

so thats not so dramatic--isnt it?

this would mean that the car was running a bit "too cold" b4 the viscous-replacement.

is there somewhere a TVR-specification on which temperatures the 280 should run?

[jeff m]

A shroud makes a hell of a difference to cooling.
My car has one, (series 1.5) at a guess I say it's a ford part with a bit cut out for the air cleaner.

Look back through some threads for someone breaking a car.

PS temps not bad, but temp climbing when driving isn't right.

Edited by jeff m on Monday 25th September 11:47

[micha]

@jeff:

thermostat is checked and operates well. an easy job to replace it, for my opinion (replaced the thermostat-housing a few weeks ago...was done in 20 minutes). filler-cap works properly too.

i found an old ford-electric-fan (blowing), which i evetually will install in front of the radiator.

[micha]

anybody has a shroud in stock and is willing to sell?