2001 Jeep Cherokee Sport, 218.000 miles. My Jeep has all the symptoms of leaking head gasket. For the past month when I start the car it misfires, shakes and engine light is flashing. It drives fine for the day. Coolant disappears very fast, no obvious coolant leaks, whitish smoke is coming out of tail pipe. Engine is not overheating. Can I use K seal to try to fix the problem temporary? I've read mixed reviews on that. Some had great results and some strongly advise against it. Thank you.
You may have a cracked cylinder head. The 2000-2001 Cherokee has a design defect in the cylinder head (casting too thin) and frequently it will crack, causing oil and coolant to mix. In the Jeep world this is known as the infamous "0331" cylinder head.
If that's the case with yours it sounds like it's been going on long enough and is severe enough to essentially destroy the engine. (Coolant gets into the bearings and damages them.)
For the past month when I start the car it misfires, shakes and engine light is flashing. It drives fine for the day
You ignored the flashing light for a month? What did that poor engine ever do to you?
If you did a quick search you'd know it means "Stop driving immediately. You are now causing damage".
Can I use K seal to try to fix the problem temporary?
It sounds like the problem severity is beyond help from mechanic in a can. I think both engine repair or replacement will cost more than the vehicle's value. It's probably time to move on.
