Is there an inherent oil pump defect on the Mazda CX-5?

My wife has recently purchased a second-hand Mazda CX-5. We now have an oil pressure warning light (which sounds a serious problem) and despite two oil flushes it's still appearing. We are now being advised it could be major job to replace the oil pump. While we recognise it's a second-hand purchase, the local garage (we didn't buy if from them) phoned Mazda to get an idea of what might be involved, only to be advised they also had two to three of the same car in their workshop needing their oil pump changed. Is there a case to say that there is obviously an inherit defect with the oil pumps with the car and despite it being a second-hand purchase (the warranty would has expired) that we have some kind of recourse to approach Mazda and seek redress at no expense to us?

Asked on 25 June 2018 by Cass Hibbert

Answered by Honest John
What can happen is the oil strainer in the sump gets clogged with sludge caused by drivers switching off their engines mid-active regeneration, whereupon the post-injected diesel intended to burn the soot in the DPF simply sinks into the sump. Removing the sump and cleaning the sump oil strainer may fix the problem and restore oil pressure.
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