Yeah, so my first post here (woohoo!!!), sadly I don't think it'll be a cheerful one. Sorry about the sarcasm, this comes on the back of having to replace the engine on wife's Acura after an oil pump failure.
I have a 97 GC, 4.0l, Automatic, 160k miles. I've had the car for 12 years, it's been great to me. No issues, no problems and no rust although it's been driven in Chicagoland. Always started up first time and frankly, I was pleased with the gas mileage - 16.7 mpg mix.
Until Monday night. Driving on the highway at 65 mph, car stalls suddenly with a check engine light. No coughing, no bucking. Just a sudden stall. Pull on the side of the road, key trick, code 11 - Crankshaft sensor. Not a big deal, we know these are finicky on Jeeps. Tried to start car, engine turns but does not try to fire. Called tow to get back home. When we arrived back, car fired right up and was driven off the tow truck into the garage. Stalled the moment it got parked!
Next morning I give it another shot, car fires right up, runs for 10 mins. No stall, no issues. Turn off and back on a couple of times, fires right up. Check Engine code clears up!!!! which means it only threw the code the 1st time it happened.
Still, given that the CPS is a known issue, I go buy another one and put it in. Only took me 1.5 hours with its ridiculous location. Car fires right back up and I take off for work. About 15 mins into the ride, there are a few small misfires, nothing big. NO attempt to stall. A few mins later, the gas needle starts to do small jumps. Aftermarket CPS are hit or miss; I clearly missed I thought.
Still car drove fine overall. Drove back home at night and noticed that for the first time in all the years I own it, the oil pressure starts to climb when I accelerate. Always used to be at 35 regardless, now it went up to 45 and even 50 under acceleration! Hmmm.
No time to work on it Tuesday night. Drove it to work this morning, exactly same behavior. Drove back home, same thing. Picked up another CPS to put in and while I was at it, I thought I'd do my annual pre-summer spark plug change and do the oil too while I was at it.
So, I get this all done. No problem, much faster on CPS this time. Fire the car up. Fires up first time. A min later starts a lot of -small- misfires, can hardly keep idle, tries to stall but doesn't. Oil pressure going up again when I step on gas. I rev it up a bit for a min, let it come down again. Same thing, running really bad, rpm needle keeps jumping.
Turn engine off and I hear a sound of liquid coming down and like a tank was emptying (gurgling sound). I look under car, coolant is coming down from the front of engine, right in front of the radiator fan. Decent amount but not huge. I feel the water, it's *cold*. Cracked hose, I thought.
Grab my light, can't see or feel a wet hose. Water pump? I walk out the garage a min, notice a BIG puddle under my exhaust! Looks like water with a hint of oil perhaps?
SOB! Go make a coffee, it'll be a long night. Back 5 mins later. I put paper towels under exhaust so I can easier see what's coming out. Start the car, runs just as rough, vey rough. Rev it up a bit, grab my light to find leak.... Wait, there's no coolant leaking!!! rev engine more, still no leaks! After 10 mins, I turn the engine off.
Still no visible water leaks. But as soon as the engine is off, I can hear liquid dripping under engine. I jump under, definitely something dripping into oil pan? I look at the water tank, way under Minimum. It was full just 2 days ago. Radiator is still full. Looking at towels under exhaust, big water puddle with a whole bunch of black spots - oil or carbon deposits?
No, I can't see foaming in the radiator. Pulled oil stick out, since I just changed oil it looks clear. Can't swear on consistency.
And there's my story ladies and gents. What do the esteemed members of the forum think? water pump or head gasket? Me thinks if the water pump gave up, I wouldn't be hearing dripping into the engine, no? what about all the initial water visibly leaking from up front?? I am quite puzzled.
Apologize about the verbose post. I always hate incomplete information although I may have overdone it this time