This jeep had been overheating on a grade . The coolant reservoir was full but radiator was ½ gallon low . I noticed the combustion gas test passed . I am a fan of reviewing codes and freeze frame first but in this situation there were no codes . So I decided to pressure test cooling system to 15 psi and cold start and this is what I found .
If the misfire disable is from low fuel as soon as the level is about ¼ tank it will run the monitor. Good tip on using the misfire monitor to see that.
Justin- appreciate the effort and tip. FWIW an emissions analyzer would have picked up on the HCs in this cooling system in about 5-15 minutes. There is no such thing as a leak too small for an exhaust sniffer…..
You may believe that is so, but it will not show a head gasket leak that only leaks under stress. Most head gaskets leak when the engine is under extreme load (70MPH on the highway, up a grade would be an example), and are fine in the bay. This is an example of a head gasket that is a different type of failure than a ‘normal’ head gasket stress leak. A sniffer is fairly useless, as it doesn't…
I know so. Ive never, ever had a leaking head gasket slip past me, I do this test dozens of times a year. This year alone at least 2 dozen times. Ironically its the Chyrsler products with disappearing coolant and intermittent over heating that this test is used on the second most in this area(the first being Subarus) I never said to test it at idle. If that's how you use the sniffer, you're…
Ah the Cuesta Grade on HWY 101… where engines go to die either lacking oil or coolant. Rudy I like to drive the piss out them a few blocks then bring it in and sniff the reservoir with the BAR-97 machine. Works great for me and takes less than 10 min total time
For those of us that have never had access to an exhaust "sniffer" would you mind explaining the correct procedure that you use?