kurtden Report post Posted December 23, 2012 I have a Cummins ISC 350. When it's cold it has a small fuel leak. After it warms up the leak stops. Any ideas what the problem could be. Share this post Link to post Share on other sites
dickandlois Report post Posted December 23, 2012 It sounds like a seal issue, but could you tell us where the leak is located. Fuel filter, fuel line, fuel pump area? Thinking the leak is in / or on the low pressure side of the fuel system if it seals up when the engine warms up. The other possibility is a leak in the fuel return path. Rich. Share this post Link to post Share on other sites
peterdube Report post Posted December 25, 2012 I have a 330 ISC My lift pump did this.It left a spot in the driveway the size of a half dollar. It's an easy fix.Just tighten the 3 1/4" bolts 3/8 of a turn and problem solved!!! Use a 7/16 sprocket with an extension. Can all be done from top of engine. Should take 20 min. Very easy fix!!!!!!!!!!!!!!!! GOOD LUCK Peter from Maine Share this post Link to post Share on other sites
kurtden Report post Posted December 26, 2012 Thanks, I'll give that a try. Kurt Share this post Link to post Share on other sites
kurtden Report post Posted December 29, 2012 I checked the 3 1/4 bolts on the lift pump, tightened them and have not had any more leaks. Thanks for the very helpful tip. Kurt Share this post Link to post Share on other sites
