Also, small point if it helps the OP - how much is a steering idler on a new car? I'd imagine that any idler, or similar chunk of metal will be the same sort of money, or more. All in all, if you keep your eye out on the heebay etc you'll find lots of nice cheap parts, and very good quality/original GM and cheaper to maintain than a new car. (because every few years the newer car will have some mysterious black box break, and be a main-dealer only thing which will cost four figures, instead of 'one off a breaker here for beer tokens'
Once you've bought that idler it'll see you out, for approx 100k. Pissys might be her original, but if it is it's done 186k...let's say it's her second, so that's two idlers in 20 years, and a theoretical couple of year-ish left in the one currently fitted.
If you really want to watch the wallet, see if anyone on here has recently fitted one and is now breaking their Omega? Beware as, anything other than Lemforder are known for
more play than a knackered MoT-failing GM one!
Once you've got the 'big' jobs done you're on a bit of an even keel, cost-wise. I've put every penny I need in my old girl in the last year, 'thrown money at her' so to speak, anything she needs, she gets. £140 in 12 months, just over a tenner a month. Versus £200 finance per month on a Hyundai with all the passion and soul of Jeffery Archer in a potato sack I'll stick to my Omega
