Coolant tank getting black inside
A leak in the High Pressure Oil System causing oil to enter the cooling system. Or, a leak in the Fuel Deliver System causing Fuel to enter the Cooling System There are several area's to consider in diagnosing the exact culprit.
Bad O-Ring Injector
Injector Cup
Head Gasket
Cylinder Wall
Failure in the HPOP/Injector Delivery System
How long has this been occurring? Does it do it all the time? Or, just under a load? Have you noticed and performance issue or anything else out of the ordinary? Any information will go a long way in helping you determine where the leak is.
That is usually caused by a combination of two issues: The injector cup may have a crack in it, and you have an injector not down tight enough to seal the combustion gasses from getting into the cup area - or maybe the copper washer lost it's seal. You could also have a cup that's split down the injector tip. Or... maybe the cup just lost its seal, but the cup is the only place that is a weak barrier between coolant and exhaust. Head gaskets rarely let go, but it is a very remote possibility.
It's not the end of the world, it's just a bit of work to replace injector cups. It's one of the less-expensive repairs to the truck if you use your own labor, but a shop will grab a bag of sand and bend you over.
That is usually caused by a combination of two issues: The injector cup may have a crack in it, and you have an injector not down tight enough to seal the combustion gasses from getting into the cup area - or maybe the copper washer lost it's seal. You could also have a cup that's split down the injector tip. Or... maybe the cup just lost its seal, but the cup is the only place that is a weak barrier between coolant and exhaust. Head gaskets rarely let go, but it is a very remote possibility.
It's not the end of the world, it's just a bit of work to replace injector cups. It's one of the less-expensive repairs to the truck if you use your own labor, but a shop will grab a bag of sand and bend you over.








