ok... i have seen this a couple times with catterpillar C-12 engines. the C-12 is an inline six cylinder engine with a power rating from approx 350hp to 425hp.i am a diesel tech and work on over the road truck engines. firsts thing first. is the engine using coolant? if so its a good possiblity the head gasket could be bad, when the piston comes up it could push air into the cooling system causing an air pocket which would cause the over heat problems. it could just be a coinsidence that you changed the oil and the temp started rising. have you seen any water in the oil. oil would be creamy white color. have you been using any oil? start there and we can see where that goes. this is just astarting point. but just out of dumbcuriosity why wont the syn 5w-30 work down there? oh and what engine is it?

 

I recently went through the ringer with a GM Dealer. It all started with the blueish smoke on the start up. Then went on further to buring 2 quarts of oil in 3000 miles. After 6600 miles and lots of documenting with the service center I started to lose coolant with no leaks.

I finally got the warranty to dig into it further. GM had a bad set of Heads cast. They crack and cause all the problems. The warranty was extended warranty and it cost them a new crate motor with my $400 contribution.

The forums on this hadn't been out to long for the problem so hopefully this helps future problems with others. I first thought the valve were bad as well and turns out it was a cracked heads.

 

I have this same problem. When I start up my C1500 after it's been sitting for about an hour, I get a cloud of blue-white smoke. I am losing coolant and oil, but the oil isn't milky. What could my problem be and what is the estimated cost?

 

My Tahoe went from hero to zero, last night. Here is the story. The driver side 3/8 hose that goes from the valve cover to the intake melted in half. We blocked it off long enough to get it home, started running rough almost home. Today we noticed the right side hose that goes from the valve covers to the breather, so the fumes get burnt again has also melted away, I replaced this too today to. I thought it may also be the thermostat because of the over heating no fluids in radaitor today replaced it. Truck want start still. Ok now crazy Question time on the passenger side of the valve cover there is a sensor/controller it has a vaccum hose that is not hooked up on the left side can't find where this goes. It is black,round and just mounted on intake with a screw left side of this controller not hooked to nothing, back side goes to intake some how, has electrical blue 2 wire connector on top. Ok now my carb has sluge (cream color) sittin in it.

 

And dont forget about those pesky intake manifolds leaking,inside outside,oil,coolant ect.

 

I bought an 2006 Silverado I now have 182,000 miles on it. I started having a blue smoke on startup. Now a Lifter went bad so I had work done on it. They replaced Valve seals, Water Pump, Cam, Lifters, Oil Pump and Timing chain w/ gears. Got it back and it smokes worse now on startup than before. Any suggestions. I am a GM person, but Dodge and Ford are starting to look better!!