'99 SD bogging/smoking

[gregpro50]

have a '99 F-250 7.3 powerstroke. 180k miles on it. All stock.

The truck runs great when it is cold. Once the engine warms up and is under load when driving it will start bogging down and losing power while throwing out some blueish colored smoke from the exhaust.

The problem is even worse if you downshift to second to let the engine brake the truck while going down a hill. When you hit the gas again it acts like the engine wants to quit and throws out a huge cloud of blueish smoke.

If you stop the truck and put it in neutral and punch the throttle it seems to clear itself out and run fine again.

I originally thought it was a problem with the injector harness but I did the Ohm test to the pins and everything is within specs.

Can someone point me in a direction here?

[orng1]

Odd that you have extra smoke and loss of power. Seems like you you might have a bad turbo. How's it boosting, you have a gauge.

[gregpro50]

I don't have a guage but don't notice any loss in boost. There is no play in the turbo shaft. My experience with turbos is that if they go bad then they go bad. If the seal went then it should smoke all the time.

[gregpro50]

Found the problem and I thought I would let you guys know...

Oil foaming.

I'm guessing it is from silicone from some recent engine repairs.

Some Fleetrite anti-foam oil additive and the truck runs like new.

[orng1]

I'm really surprised, how did the oil go bad?

[gregpro50]

The oil pan was just changed. The sealant used on the pan can make the oil foam and aerated oil loses the hydraulic ability to actuate the injectors properly.

I used Valvoline 15w40 diesel oil and the sealant was the Ford recommended sealant for diesels but it still did it. The only thing I am thinking is that I didn't wait long enough for the sealant to cure before running the engine.

The oil didn't really go bad, it was just contaminated. The diesel shop around here said the issue I had is actually pretty common after engine repairs. They also recommend to use Rotella oil since it has less tendancy to foam.

I really can't believe how well the truck runs now. It seems to idle smoother and have more power than I remember.