K-Series 1600 oil pressure.

[Chrisp5782]

I've recently picked up a 2004 1.6 K-Series car and, whilst checking it over, noticed to oil pressure gauge was reading low.
The garage fitted an external capillary type gauge to test pressure.

The readings gained were good (a little over 2 Bar on warm tickover and 4 Bar under load) I'm led to believe the original sender unit is less than reliable and prone to failure, is this correct?

How much of a drama is it to fit a mechanical oil pressure sender and are there any other options?

Cheers in advance.