Engine/Transmission (1994 - 1998) Ok, here's a puzzler... water in oil, no oil in water...

[Forrest Nearing]

knee-jerk says "head gasket", right? truck has had water in oil for 6 months now (not my truck!) Lately water consumption has gotten REALLY bad... before, the oil would be black with a thin layer of snot on top. Owner just limped it as it wasn't the primary driver. Decided that after it consumed at LEAST a gallon of water on a very short drive... the oil was changed and turned to almost pure snot with maybe 2-3hrs total run time.



Head gasket looked fine... then it hit us... how does water get in the oil without getting oil in the water? bad oil cooler would put oil in the water (oil cooler looks fine BTW)



head is cracked pretty heavily between the intake and exhaust seats... crack crosses both seats on some holes... lots of soot in the #6 intake port crack on the #6 is burnt from the combustion into the throat.



one other symptom. after the truck has been sitting, it cranks and cranks and then belches a lot of white smoke... runs clean, no evidence of water out the exhaust.



only theory I've come up with is cracks have reached water... when the truck sits, it puts a decent amount of water in the piston dish, hence the white smoke on startup... and the water in the crankcase is getting there past the rings.



problem w/ that theory is the radiator isn't pressurized.



it's got us stumped... cracked block?



truck is getting a new engine, but curiosity is driving us nuts

 

[PToombs]

When the truck is warm the cracks open up. He shuts it off, water runs in. The other possibility is cracked cylinder, but the one I saw like that pressured the water jacket, then forced water into oil. Also had oil in water.

 

[InfernoB]

Check soft/freeze plugs behind tappet cover. I forget how many.

How many miles, and how was the coolant?

 

[NIsaacs]

Is it a Dodge 5. 9? Just wonderin if it is some other make truck, it might have a water cooled aftercooler? Possible crack in the head in the intake area before the combustion chamber? Did you unbolt the intake cover plate and look under it? Was the trucks cooling system ever frozen?





"NICK"

 

[Forrest Nearing]

sorry, it's a 12v... hence posting it in the 12v Engine forum



didn't realize there were any freeze plugs behind the tappet cover, we'll pop it off and check it out

 

[LeeJ]

Ive got a 93 motor sitting at the shop right now that has the same problem Ive got a good idea that it is coming from the oil cooler there isnt very much oil in the water but there is alittle bit (you only get a glimpse of it here and there) Ive been told that there is and o ring in the cooler that will let water by when it warms up but as the motor cools down it seals up but let me know what you find out I plan on tearing mine down in about a month and seeing what Ive got

 

[Forrest Nearing]

Lee,



our confusion is... isn't the oil in the oil cooler under pressure? higher pressure than the coolant? wouldn't it contaminate the other way? oil into water, but not the other direction?



a frost plug behind the tappet cover sounds like the best/logical explanation that we haven't checked yet.

 

[NIsaacs]

If any frost plug were to leak, it would not get in the piston dish





"NICK"

 

[Forrest Nearing]

well, the chambers/pistons don't look steam cleaned, it was just a theory of mine... owner said previous engine white smoked on start up the same way as this one due to the huge injectors, timing, lower compression, etc. but it SURE looks awful white to me (not blue white like fuel)



I didn't realize there were frost plugs behind the tappet cover

 

[LeeJ]

Forrest any luck on the motor?

 

[Forrest Nearing]

haven't gotten any deeper into it... consensus seems to think it's a cracked block

 

[RonA]

I blew a freeze plug under the valve cover in my 24valve. 5/8" stream of water fills the crankcase pretty fast.



Ron