P0125 and low coolant

[ChristianA]

hello everyone, I have a 2002 B3000 ds auto. A few days after conducting my first oil change since acquiring the truck (130,000 miles) I was arriving home and noticed a lot of exhaust smoke. I put it up for the night and drove it the next morning. The smoke wasn’t getting a whole lot better, so I checked my coolant and oil on suspicion of a blown head gasket. The oil isn’t milky or frothy, and my coolant reservoir wasn’t bubbling. Everything looked fine for a couple hundred miles. I even used K seal just in case. my check engine light also came on with a P0125 Closed Loop issue. After letting the truck sit for a few days, my coolant reservoir was almost empty. I refilled it. The only issues with the truck that I know of is some low compression in one of the cylinders (50psi cyl#5, 120psi cyl#4)Anybody have any ranger-specific ideas of what it may be? I’ll appreciate anything you can tell me. Thanks!

 

[Brain75]

p0125 is more than just "closed loop issue" the full of it is "coolant temperature too low to enter closed loop fuel control" - which means either the coolant is really cold or no coolant on the sensor.

Is the exhaust more like steam/fog than smoke, no smell + no oily feel if you soak your hand in the cloud for a second(a slight sickly sweet smell of course would be a dead giveaway for antifreeze)? If so, I would say you have a cooling jacket leaking into the exhaust.

May be just a simple as a high pressure coolant leak, doesn't leak sitting parked or cold before the thermo opens, but once it opens coolant streams out.... First check for leaks thoroughly cold and hot. That would explain both the code and the no coolant issue, but not the smoke.

Oil floats on water, so the second thing I would check after really really assessing the exhaust and leak check is to do an oil change and see what comes out of the drain plug first - coolant then oil...You think you would get the chocolate milkshake effect, but I have seen coolant filling up the oil pan unmixed.