Vent Hose and What Else to Check?

[ToddJK]

Hate to tag onto an existing post but I have just noticed the same problem. I just replaced the oil pan gasket, oil pump idler gear..see other posts and today ran it for an extended period of time at high idle (brake problem prevents driving it) to get it warmed up. When it got to about 150F I noticed the same fog/smoke coming from my tube. This is the first time I have got it close to temp since doing all the work. There is no sludge on the valve cover cap. The coolant is just water at the moment as I was planning on doing a flush but wanted to get it up to temp once before draining and doing the flush.

In the last year I have only put about 10 miles on it in short trips and never noticed the smoke/vapor until today when it got warmed up. Never does it at idle, never noticed making oil or loosing coolant. I'll do the mason jar thingy but it takes 30-45 minutes at 1200 to 1400 RPM with the radiator blocked to get there. I'm hoping it's just because of all the maintenance I just did and won't do it again. It does have a small head gasket leak between the #1 & 2 cylinders right by the exhaust manifold. I believe it is coolant.

Thoughts?

Another run up to 160F and the smoke greatly dimished.

It's possible you can have a small head gasket leak into the crankcase causing the blow-by. Could be caused by shrinkage so when the engine warms up the blow by stops, either the metal contracting and expanding or it's the gasket, but it's bound to happen on these older trucks especially with original gaskets. I just wouldn't go on long trips or push it too hard for extended periods of time.

 

[Jeepsinker]

Hate to tag onto an existing post but I have just noticed the same problem. I just replaced the oil pan gasket, oil pump idler gear..see other posts and today ran it for an extended period of time at high idle (brake problem prevents driving it) to get it warmed up. When it got to about 150F I noticed the same fog/smoke coming from my tube. This is the first time I have got it close to temp since doing all the work. There is no sludge on the valve cover cap. The coolant is just water at the moment as I was planning on doing a flush but wanted to get it up to temp once before draining and doing the flush.

In the last year I have only put about 10 miles on it in short trips and never noticed the smoke/vapor until today when it got warmed up. Never does it at idle, never noticed making oil or loosing coolant. I'll do the mason jar thingy but it takes 30-45 minutes at 1200 to 1400 RPM with the radiator blocked to get there. I'm hoping it's just because of all the maintenance I just did and won't do it again. It does have a small head gasket leak between the #1 & 2 cylinders right by the exhaust manifold. I believe it is coolant.

Thoughts?

Another run up to 160F and the smoke greatly dimished.

If the headgasket is already leaking your best bet is to just go ahead and replace both headgaskets. It will fail spectacularly very soon and at a real bad time.