It appears i am loosing coolant. I noticed the overflow bottle was about 1/2" below the min line so i added coolant to bring it up to max. After driving about 30 miles it is now about 1" below the max line. The coolant seems very brown looking in the overflow but looks clean in the radiator. I really have not noticed and increase in the oil level but the oil looks thin and not nearly as black as normal.comparing the oil from my brothers 12valve it is thinner and not nearly as black. The truck sounds very noisy but it is running fine. No excessive smoke, starts right up, and plenty of power. There is no bubbling into the overflow or the radiator.

Does this sound like the oil cooler leaking or the trans heat exchanger? Any other suggestions? what should i look into next? What would the oil look like if the coolant was mixing with it?

 

Usually if there is coolant in the oil the oil will foam up when the engine is running. Look under the fill cap and see if it looks milky white from coolant mixing in the oil.

 

If you feel that its the heat exchanger i'd check the trans fluid level. Smell it, make sure it doesn't smell like coolant. Otherwise would you have a reason to expect a head gasket leak? Did any burnouts or have to out-do a newer diesel truck lately?

 

Trans fluid smells fine and looks fine could not check the level due to it not being hot. No real hot rodding I have had the valet switch off (less fuel) for months.

 

smell the oil make sure its not diesel contaminated. coolant and oil looks like a chacolate milk shake. not thin.

 

hmm... what would cause diesel in the oil? front pump seal and lift pump?

 

Those are the two spots for fuel leaks that i know of.

Another possibility is a slow leak at the water pump and its just being blown around by your fan. Also check your rubbers for cracks or loose clamps. Mine loosened up on me the other day, i replaces that sucker.

 

there are no external leaks.

 

I dont know if the b can do it but the ntc cummins inj. can also put diesel in the oil. I would check the lift pump first then take the oil fill off and check the ip.front seal next,then inj.

 

The injectors are not cooled by coolant.