So I replaced the the engine in my truck with a "low mileage" 5.9. The one we pulled was thought to have a burnt ring, but actually had a cracked head that sealed when tested. The "new" motor had two cracked heads and a whole lot of varnish. So I stripped the "new" motor down and ordered some aftermarket steel heads with better castings. After assembling the whole lot I ended up blowing white smoke from the exhaust. I choked it up to a blown head gasket, but decided to use a "block tester" after a lack of milky oil and bubbles from the radiator. The "block tester" tested negative for any exhaust gases in the collant system. So I figured that left me with an intake manifold gasket leaking a small amount of collant. I recently found time and replaced the intake gasket and, though greatly reduced, have white smoke when I start it up and then if I pump the throttle a few times. It doesnt heat up and I dont seem to be loosing coolant. I'm at a loss, but will pull the plugs and check the compression tomorrow. Any help here would be greatly appreciated.

 

The exhaust might still be full of oil or coolent from before when the old motor broke ?

 

Compression test will tell what's up. Do a dry test and then do a wet test by squirting a little oil into the cylinder to get the rings to seal better. If the wet test is drastically higher it's time for a bottom rebuild

As long as they're all within 10% of each other and 100 PSI minimum is what Chrysler says but that seems low to me

Sounds like it indeed does have a burnt ring, or maybe a couple.

Did you keep the stock valvetrain?

 

The coolant/oil in the exhaust is highly possible, but I've driven it a couple of days in a row. My drive is only a couple of miles and it was raining on and off while the exhaust was open.

The valvetrain is stock. Besides the heads its a used bottom end with new oil-pump, timing set and a pretty aluminum plate for the leaky intake.

I have my wife's cars (yes, cars as plural) to work on today, but am hoping to give some attention to the Ram tomorrow. I'll let you know what happens.

 

If it's just at start up and slightly after you could have leaking/non sealing valves. A compression test will reveal a lot

 

Finally got around to the compression test today. Dry across the board with a solid 140-150 on all cylinders. Cylinders 2 and 8 had oily residue . I cant tell if it is oil in the cylinder or the anti-seize I put on the plugs. I did collect some of the dripping fluid from the exhaust pipe and it is clear without a black or green tint. I'm at a loss at this point and need to figure out the next step.

 

Have you driven the truck for an extended period to burn off the excess oil and moisture that may have collected in the cat and exhaust pipes (a nice highway ride for about an hour or so)? If not, that may help to see if this is a residual from the last engine swap.

 

I'm starting to think that it is from the trip cross country. I plan on replacing the Cat and the muffleer (always wanted to remove the stock for an SUV Flowmaster) to ensure they are not holding oil from the origional cross-country drive.

 

An update for the last couple of months. I tested the radiator for CO2 in the coolant system and found out that everything was good. No leaking, no nothing. So I decided that it was antifreeze (or possibly light oil) left in the cat or muffler. So I replaced the cat with a flowmaster set-up. Still smoking, no coolant use or pressure in the system and no chocolate milk in the crankcase. I am at an absolute loss at this point. Anyone with any ideas?

 

Does it continually blow white smoke or does it stop after a little while? I've found with mine that it likes to hold a bit of moisture in the exhaust system, so it'll blow out some white smoke on start-up, but then it stops and you only get the typical light white smoke due to the cold temps. Just something I've found.