We have 2 80 series. Both have oil light staying on. The N reg had a bit of a roasting. Replaced radiator but oil light stays on. Any thoughts?? The R reg just went thru Mot. Oil light is coming on then off then back on flashing then goes off. Both cars oil levels all good. No leaks can be seen . R reg driving fine. N has occasional lag when picking away (this one got roasted) any info or suggestion appreciated.