P/S Pump - 11 Bar vs 12 Bar

Post by **chrism** » 14 Jul 2017, 23:01

My wife's 2005 S80 has a rather noisy P/S pump. The tag on the pump says it's rated at 12 bar. All I could find at the Pick-n-Pull yards are 11 bar pumps so I grabbed one. Would it be OK to swap out the 12 with an 11? I suspect that either pump supplies more than enough pressure under normal circumstances but are there any P/S experts in the house that can offer opinions?

Post by **oragex** » 15 Jul 2017, 17:10

Check well as there are two models with different pulley diameters. Most of the times noise is from wrong fluid or loosen pipe connection at the pump or reservoir (or even something stuck inside the reservoir if it's the old type with the return line near the top) allowing the pump to suck air.

Post by **chrism** » 16 Jul 2017, 07:13

I don't have the car here right now so I can't compare pulley sizes. I'll be mindful of that when I get into it. I'm certain the fluid is topped up and all the hose connections are tight. The age of the fluid is a bit of a concern though. Since I was going to flush it anyway I will probably go ahead and do that first before removing the old pump just to see what that does. I'd be surprised if that alone quiets the pump but hey I've been wrong many times before.
Thanks.

Post by **darrylrobert** » 26 Sep 2020, 20:13

It think it makes very little difference, my pump was also making same noise and i swapped it which fixed it. I prefer heavier steering so i would choose 11 bar.