I recently had a service on my 98 gt turbo impreza I fitted iridium plugs and the oil I used was called eneos 0w50 race oil but now when my car gets hot my oil temp gauge reads 100degrees but before it used to read around about 85 and my oil pressure on start up is about 6.0 but when it gets hot it reads about 2.2 which it didn't go that low before can anyone tell me if this is normal?