2003 4.2L Hemorrhaging Oil in Cold Temps

[Quadzilla724]

Last year I let my son borrow my 2003 Trailblazer (4.2L LT EXT) to go to the hockey rink. He called me from a gas station saying it was 'smoking' and smelled like it was on fire. I go to find it appeared oil was leaking on the block. At the time it was negative degrees and the truck was parked outside. I took it home, topped off the oil and had no further problems.

No problems in the Spring, Summer or Fall. Now this winter. The truck is garaged all the time when not in use so again no problems. It snowed several inches here two days ago so I let me wife take it to work rather than her Saturn. It was -11° that day. The TB was parked in her work parking lot for 8 hours. She comes home and says the TB is burning. I go out, open the hood and see smoke coming from the left side of the block (from my perspective looking in). It looks like a stream of smoke both high and low. I check the oil. Not a drop on the dipstick. I asked her if there were any warnings or beeps during her half-hour interstate drive and she said 'no, it drove fine'.

I put three quarts in. Two days later in the garage, I take it out. I still smell the burning and notice a huge puddle of oil on my garage floor. 18" x 12" puddle of fresh oil. I drive to the gas station and purchase more oil. I check dipstick before I put it in and it shows the oil is topped-off. It appeared it hadn't leaked any of the three quarts I put in.

I can only assume the oil on the floor is leaking from when my wife brought it home. The oil I put in seemed to still be there and the puddle was probably from when my wife brought it home.

So it seems the hemorrhaging of oil only occurs when the truck is sitting in freezing cold weather and driven. Is there an explanation for that?

Through the entire ordeal, the gauges and warning lights showed no sign whatsoever of anything wrong. Minus the smoke and smell, the truck drive perfectly and the oil pressure gauge maintained a normal reading. No warning on the display of 'stop engine now', etc.

What is happening here? Thanks for any information.

 

[The_Roadie]

Welcome! There's certainly no prevalent design defect or numerous reports about oil leaks when cold. Any other maintenance history?

I'd clean it all off then the leak should be easier to spot. Remove the oil pan skid shield if you have one. Check the oil filter and just above it the oil pressure sending switch.

Note that the I6 engine does not have a traditional honest oil pressure gauge. The sender switch is SIMPLY a 12 PSI on/off switch; the number you see on the gauge is a BIG LIE put there by the designers to fool the average owner into thinking they have some accurate data. Until the pressure goes to zero on the gauge, all you can conclude is you have something over 12 PSI. Yes, we really, really hate this aspect of the vehicle, which GM tried to conceal from us but the truth is in the factory shop manual.

 

[triz]

Was there any maintenance done before. Someone check the oil or add and forget to tighten the cap?

 

[IllogicTC]

Any ideas on anything that may be affected by temperature, like seals/gaskets, or maybe the oil itself (if one's not using the 5W-30 as the manual recommends)?

Do as instructed and clean the passenger side of the block well, check what you can, then give it another whirl. I imagine that something is making oil contact the nice hot exhaust manifold which is making the smoke you're describing. You're lucky it hasn't turned into an engine bay fire but since you've noted the problem and come to the right place, hopefully we can help before something like that happens

It'd also be worth checking out the upwind O2 sensor if you determine oil is contacting the exhaust manifold, just to make sure none got on there and was heated where it could damage the sensor or the associated wiring, or you'll just be in for more crap down the road.

Note that that's just my theory. Could the famous "warped heads" be causing such an issue, anyone think?

Or maybe worn valve guides or seals? Could allow oil to seep down around the stems and collect in the combustion area as the engine cools - this in turn would cause smoking out of the tail pipe, and possibly the exhaust manifold (especially if it's cracked which seems to be a fairly common issue).

 

[triz]

Illogic had me tinking about the CPAS. That is what came to mind that leaks oil after awhile. Check your boots as well underneath, Make sure its not kicking up any oil.

 

[IllogicTC]

CPAS is another good thought. The O-Ring seal may be affected by the cold, and plenty of stories of the electrical connector getting filled with oil, etc. etc.

Your CPAS is located besideyour power steering pump, in the side of the block. It'll look like a simple connector plugged into a round part that goes into the side of the block toward the upper end of the front, with the round part having a flange coming off it to secure it with one bolt.

 

[Quadzilla724]

CPAS is another good thought. The O-Ring seal may be affected by the cold, and plenty of stories of the electrical connector getting filled with oil, etc. etc.

Your CPAS is located besideyour power steering pump, in the side of the block. It'll look like a simple connector plugged into a round part that goes into the side of the block toward the upper end of the front, with the round part having a flange coming off it to secure it with one bolt.

I've never had any maintenance done on it. OK, I'm not a mechanic so bear with the crude guidance toward the problem. Last year, I recall when this happened, the oil seemed to seep directly from a specific spot that I'm about to describe.

The very top of the engine that is plastic and has the word 'Vortec' on it is bolted to something, I'll call that 'Hal'. Hal is bolted to something down further and I'll call him 'Fred'. The oil is seeping from the joint between Hal and Fred and dripping down all over the place. Did that make sense? Again, this ONLY happens with the truck is sitting in extreme cold temps (below zero) and then driven. I do not have any problems whatsoever when it's warmer or the truck is garaged.

If I recall correctly, last year while investigating this, the valve cover gasket come up in conversation.

 

[IllogicTC]

Valve cover gasket may be in the right direction.

'Hal' only sits on top of 'Fred,' pretty much. Just a piece of plastic held on by two bolts, and a couple hoses. 'Hal' pretty much is just like a hat for the actual engine, to keep this in relative terms.

'Fred' is the valve cover. He bolts on to 'Frank,' the cylinder head. There's a noticeable line between where 'Fred' and 'Frank' meet up, and I believe you may see the gasket separating them. Check along it for oil. If it appears to be coming from higher, between the plastic 'Hal' and the metal 'Fred,' unbolt 'Hal' and take a look around. He's really easy to remove. Straight screwdriver to loosen the hose clamp on either side (the big hoses in back). A 10mm socket with extension to get to the bolts, there's only two on the left side. There's a hose on the bottom of 'Hal' toward the front, connected to 'Fred,' just pulls right out. Lastly there's a wire harness loom on the back of 'Hal' on the left side, use the straight screwdriver to pop it open. Then lift the whole thing up and to the left.

 

[RayVoy]

A lot of theories, actually "Hal and Fred" have some credence, I think. It sounds to me like a return passage is blocked with cold temps, or the engine is somehow sucking the oil out of the crankcase, or blowing it out of something like the level check tube.

I do know, if it was me, I'd leave it parked outside on a cold night, in the morning start it with the hood open and watch for a leak. From the sounds of things, it shouldn't take long to spot it.

 

[IllogicTC]

Do a nice underhood detailing too, beforehand. Doesn't have to be spotless, doesn't even have to include the driver side of the bay, but it'd make it a lot easier to spot.

 

[Quadzilla724]

Do a nice underhood detailing too, beforehand. Doesn't have to be spotless, doesn't even have to include the driver side of the bay, but it'd make it a lot easier to spot.

Thanks guys. I will have plenty of opps for cold temps this week. I'll let you know what I find.

 

[Texan]

In case you missed this thread, I would suggest that you review it.

Vortec 4.2L I-6
oil everywhere

 

[Quadzilla724]

In case you missed this thread, I would suggest that you review it.

Vortec 4.2L I-6
oil everywhere

Do you have a link or should I search for that.

BTW, I didn't get a chance to test the theory in the sub-zero weather we had immediately following and it hasn't been that cold since.

I've had no problems with leakage since, although the odor of burning oil is ever-present which I assume is residual from the original problem.

My son did borrow the truck and it sat in a parking lot for 3 hours for a hockey game in 9 degree weather. This caused no problems. So far, it's only been sub-zero for at least 8 hours.

 

[Quadzilla724]

Do you have a link or should I search for that.

BTW, I didn't get a chance to test the theory in the sub-zero weather we had immediately following and it hasn't been that cold since.

I've had no problems with leakage since, although the odor of burning oil is ever-present which I assume is residual from the original problem.

My son did borrow the truck and it sat in a parking lot for 3 hours for a hockey game in 9 degree weather. This caused no problems. So far, it's only been sub-zero for at least 8 hours.

OK, I searched and found the thread. My question is wouldn't a gaping hole like that continue to cause issues regardless of conditions? The odd thing is, the TB runs perfect otherwise. It's only done this twice; once this winter and once last. The pattern is the truck being left out in sub-sero temps and driven. I did go out and look for a similar hole. There's no obvious hole, but I never cleaned the block and from what I can tell the oil seeped from the valve cover down.

 

[Texan]

OK, I searched and found the thread. My question is wouldn't a gaping hole like that continue to cause issues regardless of conditions? The odd thing is, the TB runs perfect otherwise. It's only done this twice; once this winter and once last. The pattern is the truck being left out in sub-sero temps and driven. I did go out and look for a similar hole. There's no obvious hole, but I never cleaned the block and from what I can tell the oil seeped from the valve cover down.

Sorry to mislead you. If you look at #29 you will find a Service Bulletin 05-06-01-014.
It shows the GM thoughts on this subject and the availably of a vented oil fill cap.
Also discusses the freezing of moisture in the vent hose between the valve cover
and the intake air resonator. Just trying to help.

 

[IllogicTC]

Sorry to mislead you. If you look at #29 you will find a Service Bulletin 05-06-01-014.
It shows the GM thoughts on this subject and the availably of a vented oil fill cap.
Also discusses the freezing of moisture in the vent hose between the valve cover
and the intake air resonator. Just trying to help.

There's also a TSB about temps under -10 fahrenheit causing oil seepage out of the front and rear main seals. I'll look up the specific number later, right now I'm getting ready to go fix an oven

If you have the TSB pack I uploaded a while back, have a rummage through it, it's in there somewhere. Well it's not technically a TECHNICAL service bulletin, I believe it's just INFORMATION, which is pretty much a "we have this problem and screw you, that's just the way it is."

And thanks for getting around the forums and trying to help people out. It means a lot, you seem like you've seen a lot over the times and that's very valuable.