I first noticed this loud squeak from the engine compartment about 5 months after I had bought my 1998 Ford Escort ZX2. I bought it in January 2001, when it already had 100,000 kilometers on it. I complained about it in June before my extended warranty ran out. Maybe the warmer weather has something to do with the problem becoming worse. The Ford dealership could not find the source of the problem, which was not very persistent at that time.

I took the car on a 3-week family vacation and the problem became progressively worse during the vacation. It was extremely annoying and even embarrassing going through downtown Calgary with this very frequent intermittent loud squeak, on almost as much as off. My brother-in-law, who is a mechanic in Winnipeg, could not identify it. When we returned home to southern Ontario, I took the car several times to the dealership to get it fixed. First, they thought it was the power steering lines, then the alternator (new alternator), then the transmission (rebuilt transmission), and, finally, they opened up the engine, did some cleaning around, and changed the PCV valve. That eventually fixed it.

The problem did come back when, a couple of years later, I got the PCV valve replaced again. The garage that replaced the PCV valve did not believe that was the problem as it was a brand new valve. At the next oil-change, I got the oil-change guys to look at it, even though the new valve was still good. They showed me the recommended PCV valve for that engine and it was slightly different from the one that was currently installed. Their replacement fixed my problem again.

A few days (weeks?) later, when I was at Canadian Tire, I looked through the PCV valves listed for the ZX2 and noticed that different valves are recommended for the 2.0L DOHC and 2.0L SOHC engines for that car. Apparently, two engine types were fitted into that model car. Mine is a DOHC model and, if the PCV valve listed for the SOHC engine is used in my engine, it causes this very loud and annoying squeak.

Some garages don't seem to know this. Perhaps, their manuals only list the one PCV valve, I don't know. All I know is that, at least once, I got the wrong one when it was replaced.