i changed my oil and filter a couple 0f days ago and since then the oil has gone a dirty black colour, it looks like its 12 months old. i am wondering if i was given the wrong filter as it wasnt a genuine part and maybe isnt doing its job. when i compared both filters the mazda one looked slightly different inside, it had what looked like a disk where as the other filter had a spring in it. also i put 5-30 semi syn oil in instead of 5-40 full syn that was put in by previous owner. any ideas pls. cheers neil ryan. uk

 

Perhaps the old oil didnt drain completely and made the new oil look older than it is? It seems to me like the oil starts to look dirty fairly quick in my car, it might be normal, or maybe we both just need to run some cleaner through our pans...

 

well remembrer only 3.7 qt comes out and i belive the whole system including the oil cooler(s) hold about 7qt or so..so once the new approx 4 qt mixes with the other dirty oil it's gonna b black!

 

This was along the lines of what I have always thought

 

good point, makes sense to me, if there was something serious i would imagine the oil pressure gauge would give it away, thanks for responses. neil. uk.

 

^well acutally the oil pressure gauge is basically an on off switch....if there is any oil pressure at all it moves to the same exaxt pressure reading if there is no pressure(basically a split second before ur motor is trash) it goes the whole way down to the left..

so basically the press gauge is not a good tool to watch!....everything seems find the only way to get fresh clean oil all the way arond is drain the oil coolers and pan when changing