Vacuum pump

[busyguy]

Posted this on IRV2 and didn't get many response's So thought I would try here.
I have a 2000 Harney and the vacuum pump that controls the Heater and A/C is making a lot of noise and seems to run all the time.
I have found the exact replacement for $213.00 on Amazon and also one that looks almost the same for$53.00.
My question is. Is the rattling noise normal and will it have to be an exact model to replace it? Plenty of room for R&R. Every thing works fine. Just don"t like the constant rattle.
Thanks
Busyguy

[busyguy]

Thanks guys
Will get out and check for a tank and also leaks as soon as it gets warmer. Had 2 inches of snow here and 24 degrees this AM in Madison ,Ga
Busyguy

[ScottG]

It's not the pumps fault, you have a leak someplace and the new pump will run constantly if you don't fix it.

[sch911]

Have you checked to see if it has a vaccum reservoir in the system? That could be bad causing the pump to run all the time.