Elusive Oil Leak on 2003 Infiniti I35

telseg

I own a 2003 I35 with about 115k. It started leaking oil about a year ago and I have been attempting to get a fix for it ever since. It is a small leak that appears to be coming from the passenger side center of the engine that leave a few drops of oil while parked. It seems like it happens only when the engine is cold or the car has been sitting for hours. The first service station I brought it to replaced the oil pan seal. This didn't fix it. I brought it back to them multiple times and they claim they could find anything leaking. I brought it to a different service station recommended by a family member. This place also recommended replacing the oil pan seal. Ok, I had this done within the past year, but maybe the first repair wasn't done correctly? I didn't have much faith in the other service station so I thought this was a possibility and agreed to have this other service station do the repair on the seal again. Well, $220 later here we are again, the next day after parked overnight the same leak in the same spot. Help! I plan on bringing the car back, but just wondering if anyone has experienced a similar leak with their car that could help narrow down where the problem could be.

peterpan99

The leaks may be at the valve cover gasket, timing chain cover, or main engine gasket which would leak only when the engine is cranking at high speed.

At about 100K most cars would have a few loose bolts or nut on the engine. Toyota and Lexus recommend tightening all bolts and nuts each 100K check up and tune up, especially the bolts that hold together oils sealing surfaces. Some of those bolts are hard to access and need special tools to tighten.

Have your mechanic tighten all bolts and nuts, run the car a few days and check for leaks. Chances are the tightened bolts would fix any small leaks.

If it still leaks, wipe clean the engine down with solvent or degreaser, then wash it down clean with high-pressure hose. When dry, blow flour or baby powder on all joints that may leak oil, find the exact cause or locations, then fix them accordingly.

If still cannot find and fix the small leaks, you just have to learn live with it. Leave a piece of cardboard under the engine to collect oil. All engines will leak oil after 100K - 200K miles. Just add oil regularly. Oil is cheap compared to what you pay for gas every week.