Hi I recently took my car (UK FORD FOCUS TD 1.8 2001 MODEL - Diesel 51 Reg) to a local garage for just an oil change. After I got the car back I noticed a strange screeching noise that wasn't there before. The noise only appears when the car has warmed up with the temperature gauge in the middle of hot and cold. It is not there until the car has been driven for about 10 - 15 mins. I took it back to the garage who checked it over and said they could not find any problems apart from a slightly loose air pipe clip which they told me should fix the problem, however once the engine was warm again the noise returned. The noise is more noticeable when the accelerator is pressed and the car revved. The best way to describe the noise is it sounds very like the noise a car makes when reversing, that kind of screeching sound but not as high pitched. It's not constant only when revs go up or accelerator is pressed. It seems to get louder as the car is driven for longer. If i sit in my car after it is warm and then rev my car the screeching noise appears. Does any body have any ideas? It's not a fan belt screeching but a different kind of sound almost like a vacuum cleaner noise...sorry hard to explain! The mechanics listened to it but couldn't pin point where it was coming from.
On another note the same garage has just replaced my water pump, and drive and alternator belts etc due to a chirping, squeaking noise when engine was cold...this was when they told me the screeching noise caused by the earlier oil change may of been fixed by a lose air pipe clip but sadly it hasnt.
Could it be a faulty oil filter? or even wrong oil? Though wrong oil seems unlikely perhaps a faulty oil filter, could this cause a noise when engine is warm? As mentioned there is no noise until car gets warm after 10 - 15 mins. Apart from the noise the car seems to run fine though the noise is very annoying as it is quite loud.
Any advice would be helpful, hope I haven't rambled too much on my first post!