Mark IVa cooling fan problem

I have a slight problem with my Mark IVa: When on full power, the amp's cooling fan is way too loud. I play mainly only at bedroom volume. When playing on tweed power, it's okay. I don't think it's broken in any way.

I've heard, that A-version has louder fan than later version. It's that true? Has anyone had similar problems? Can I just disconnect the cooling fan? Or can I upgrade it to more silent cooling fan. Which one do you recommend?

I've had some that were as loud as a Piper Cub. You can rebuild the old Howard to make it quiet again,
but it's just easier to buy a new Globe Motors fan from Mesa. It's around $ 25.00 and is way quieter.

Thanks for the answer. Yes, it's the old Howard cooling fan, and it's about 20 years old now. So I think it would be better to just change it.

Do you know what would be the exact model, if I'd buy new Globe Motors cooling fan? Those are hard to find from here at Finland.