Check gasket for coolant loss

Dear Doctor: I own a 2013 Ford F-150 with the 3.5-liter EcoBoost engine with 20,000 miles. The truck is losing coolant and I have to add more every couple of weeks. I visited two Ford dealerships and after running pressure tests they both told me there is nothing found. If there are no leaks found, then where is the coolant going?

— Joe

Dear Joe: If you’re adding less that one quart a month, then have the dealer check and mark the coolant level, and then return in a month. If the coolant has gone down a half gallon or more and there are no signs of any leaks, then the engine may have an internal head or head gasket leak. This can be checked with a gas analyzer or bottle leak check at the coolant fill. If the truck is out-of-warranty, then I recommend adding one bottle of a good “stop leak.” I recommend it to my customers and they are pleased with this as a solution.

Dear Doctor: I have a 2003 Nissan Pathfinder with 150,000 miles. It’s giving me a problem with intermittent starting. The engine cranks but doesn’t start. I have to try it three or four times to get it to start. Also, when sitting still at a traffic light the vehicle shutters like it’s going to stall. My mechanic put in a new battery, air filter, gas filter, spark plugs, crankshaft position sensor. He also cleaned all the coils and injectors. The computer is not giving any fault codes. We are out of options on what the problem could be. Do you have any idea what to try next?

— Theresa

Dear Theresa: We need to go back to basics. The easiest check will be for ignition spark. The technician needs to connect a spark checker and tape it to the lower part of the windshield and when the engine does not start you can tell the technician if there is any spark. This is the first step. The next step would be either a fuel pressure or fuel injector pulse. Another way of checking is with a scan tool. The technician will look at the cranking rpms and fuel injector pulse width in order to make sure the engine has both.

Junior Damato is an ASE-certified Master Technician. E-mail questions for publication to Mail questions to Motor Matters, P.O. Box 3305, Wilmington, DE 19804.