Knocking from ventilation system

[AlBundy]

I am finding that when I turn the internal internal cooling fan on to full power, there us a knocking and rattling coming from behind the dashboard, almost like there is a ping pong ball in there.

Is there a way that I can try to find and fix without removing the dashboard?

If I have to remove the dashboard, is that a DIY possible job, or do I need a professional?

Thanks in advance.

Al

[Aidan]

Removing dash is relatively straightforward in principle but age and especially rust can make it hard (5 screws close under windscreen can be a pig if heads are rusty as you are working at an angle with little clearance for tools. Plastic parts break easily as they are brittle after many years in the sun. Instructions are in Bentley manual, and I guess there's some guidance in the Haynes manual too as heater fan replacement isn't uncommon. Usually noise is the systems way of telling you that there is something wrong, but it is possible that there's a foreign body in there that has made it's way in via vent outlets. Is it otherwise quiet in operation ? Maybe not use fan on 3, it's not too hot at the mo, I just have mine on full fresh air and let the force of air as vehicle moves do the work and open window when stationary/stop start traffic, I don't use the fan much except to clear windscreen when it is cold and steaming up

[Porkscratching]

As "CovKid" used to say; if you have to remove the dash, think of as many jobs to do behind there as you can (he always advocated upgrading audio speakers taboot) as it's definitely an investment in time and effort and as Aidan says with the windscreen in situ the very first of the process can be character enhancing.

I have a replacement motor and personally apart from demisting I tend to use it mostly for bringing the water temperature down when the old girl is labouring up hill etc. Windows open, heaters on FULL. I think we've all been there!

Regards, Max.