When I start my 96 Disco TD300 from cold, the viscous fan seems to be blowing an awful lot of cold air around - can they go bad and start locking up when they're cold when they're supposed to freewheel?
Tony
Yup.
Mine's always done it. A simple test is to start the engine from COLD. let it get to a reliable tickover then use a stiff yard-brush head or something similar to stop the fan ... the engine should still be COLD. It should take a bit of effort, but it should stop without affecting the engine revs. When the engine is hot it shouldn't stop the fan as the viscosity has changed and is powering the fan properly.
When I start my 96 Disco TD300 from cold, the viscous fan seems to be blowing an awful lot of cold air around - can they go bad and start locking up when they're cold when they're supposed to freewheel?
Tony
Yes !!!
It has been recommended that I remove the fan altogether which I'll be trying out very soon. Who else has done this out of interest?
It has been recommended that I remove the fan altogether which I'll be trying out very soon. Who else has done this out of interest?
I've fitted electric in the past which made sod all difference to economy but did make the car a little quieter.
I'd be reluctant to totally remove a fan, its there for a reason and also cools the intercooler. If its busted then fix it otherwise next job will be finding a cylinder head that isn't warped to fit.
Lee D
Yes, but not on this model. See the discussion on radiator muffs last week.
Removing a viscous fan does have the down side that it's not a quick job to refit should you need to do so unlike e.g. on the Series models.
All viscous fans that I've come across will appear 'locked' from a cold start. After running for about 30 seconds they will 'quieten down' indicating, at least, some degree of functionality. It doesn't prove the temperature control components but rules out a completely seized device.
Incidentally, it's the temperature of the air passing through the radiator core that controls the viscous fan function. That is not necessarily the same as a hot/cold engine.
I'd be tempted to use the radiator muff solution on this model. It's the only way that you'll reduce the flow of cold air over the engine block without the other down sides.
This model can cook its cylinder head so make sure that your temperature gauge works and use it!
As others said, yes they can lock up permanently as a "failure" of sorts. Not sure about the wisdom of trying to stop a suspect fan when the engine is running, even with a broom, handle! Best to just try and move it by hand WITHOUT the engine runing, but cold. it should move easy. If *Very* stiff, or locked, then the viscous hub has probably failed.
The 200TDi in my hybrid has no engine driven fan. But there is a huge (the largest Pacet job I could fit in there) fan that run's all the time at a slow speed, fed via a large 1 ohm resistor whenever the engine is running.
If the water temp sensor says so, the fan get's full power, and almost sucks the LR along by itself, cooling things down nicely.
Regards.
Dave B.
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