I have a 2004 Murano with 130,000 miles and it is inconsistently leaking coolant. A couple weeks ago I checked the coolant reservoir and it was pretty dry. I brought it to a local mechanic who pressure tested the coolant system and was unable to find a leak. He suggested the inconsistency may be a sign of a bad water pump. I then brought it to a different mechanic who pressure tested it and said the head gasket needs to be replaced.
This seems a little bit curious that there were two different diagnoses of this issue. My little knowledge of cars would lead me to believe that if the head gasket was damaged then the first pressure test would have revealed a leak somewhere in the system. Also, there is no white smoke in the exhaust, and there does not appear to be any coolant present on the oil dipstick. However I have little knowledge of this issue and car mechanics in general.
Can anyone shed any light on this problem? Any thoughts on how to proceed since I think there is a significant price difference between a water pump and a head gasket?
I hate to say this, but I think a third opinion may be prudent. Ask your coworkers and neighbors who they trust to work on their cars and then let him take a look at it. Hopefully it is nothing more than a leak in a coolant line.
Coolant do need to be top off periodically. The water in there evaporates. When was the last coolant change? If you never add coolant between changes ever then maybe its time to do so. If no leak on the floor is found and your engine bay does not smell sweet _ no coolant smell after a drive then probably there is no leak. Fill the reservoir to the max line and observe. Reservoir level also goes up and down as the coolant temp. increase and decrease. Good luck.
I brought my Murano for a third opinion (a Nissan dealership) and they diagnosed a cracked oil cooler tube and a bad oil cooler seal. The cost was just over $300 for both of them, which is significantly better than the ~$3000 I was expecting for a head gasket. It seems to have fixed the problem since I have not seen a leak since they fixed it several days ago.