Then it is probably the M43 engine which is pretty much the same as my 318i which has the M40 engine but with main difference is it is chain driven thus being better and not having to change the cam belt every 3 years as I do. This engine is fitted to my 316i compact which is coming up to 130000 miles and again has no issues and is still 'tight', I did replace water pump,thermostat and plastic coolant pipes as these can fail after a long period but as far as the main engine is concerned it is all good as it had regular oil/filter changes. Hope this helps,Mick.