Oil Consumption

[nonickatall]

Hello,

I currently have a relatively high oil consumption, around 1 liter per 1000 km. That's appx. 1 Quart per 600 Miles.

The engine currently has 220,000 km (136.00 miles) on it, runs perfectly and does not consume excessive fuel. There is no pressure on the crankcase so no blow by problem. It doesn't smoke much, when I drive normally. I think the PCV valve is OK. Yesterday I drove faster on the German highway and accelerated the car to top speed appx. 112 miles and drove for about 20 km.

Then I came home, I live right next to the motorway exit and it's still a bit downhill, so I drove to my place in coast mode.

This morning I turned the car on and a huge gray cloud came out of the exhaust.

To me it looks typical of worn valve stem seals.

I've noticed the phenomenon more often recently, that it smokes gray in the first few revolutions. I know that the cylinder heads were reworked during the installation of the LPG gas system, but I don't know whether they installed new valve stem seals at the time.

In my opinion, the valve stem seals are very suspicious. I know this from BMW vehicles that have already had the valve stem seals worn at 170,000 km.

Is this a typical problem with our cars? Are the valve stem seals designed in such a way that oil can still flow into the combustion chamber, when the engine is switched off, which would explain why it smokes significantly for a short time after it is switched on?

Or am I on the wrong track and that could also be another problem?

Best regards from rainy and cold Germany

 

[drdave81]

Since you said someone did work on the heads, I would take it back to them. What all did they do to the heads, how long ago was this done?

Piston rings aren't typically something that goes bad on these engines, so I would tend to lean toward the valve seals, especially since you said someone was in there. And if it only smokes on first start up, that's also another indication of guides. Rings would tend to smoke more than just start up or after idling.

 

[Mudsport96]

Still early morning here so I'm doing my best to think clearly. So, your Escalade has 170,000 km on it right now? If so that is roughly 105,000 miles. I would not think that your valve guides are worn. My Silverado did not start excessively consuming oil and making valve noise until 390,000 miles, or 628,000 km. So I am fairly confident you have a few kilometers till your guides are worn badly.

Now, if I remember correctly, you do have a 2006. So AGE may have taken its toll on the valve guide seals, and they COULD be leaking. They are not terrible to do... however they are not fun to do if you don't have the space or equipment to do them with the heads on the engine.

However, your rate of consumption seems high for just guide seals.

In 2003 General Motors switch the PCV valve from the old rattle valve to a fixed orifice that continuously pulls a vacuum. It is for lack of a better description, a controlled vacuum leak. There were a few revisions to correct heavy oil consumption by these engines. The drain holes in the metal deflector were enlarged to help keep the oil from clogging them. The clogging lead the imitation pcv to act as a straw and suck oil out of the valve covers. You couldn't really see oil smoke at highway speed but you could on startup and heavy acceleration.
I cured this on BOTH of my 2006 5.3 vehicles (Tahoe and Silverado)by installing an older style PCV valve cover from 2001 vehicles and an oil catch can on them.
The Tahoe has gone to virtually zero oil consumption between oil changes. The Silverado has dropped from 2 quarts per 1500 miles (1.9 liters per 2400km) to 2 quarts every 3000 miles ( 1.9 per 4830km). But it also has now 414,000 miles give or take ( 667877.76 km approximately). So oil consumption is expected.

If you have the ability to do some fairly easy work on it, I would start by inspecting the inside of the valve cover where the "PCV" is and see if the drain holes are clogged. I personally think that is possibly your culprit. And it requires just time, a little cleaning solution( degrease liquid), some pipe cleaners to clean the little holes and maybe a valve cover gasket set. Fairly inexpensive here in the States. But, it is winter... so if you do not have an indoor place to work, it can get a bit cold.

 

[nonickatall]

Thank you very much for the comprehensive answer.

My truck has 220,000 km on it, but that's not much more. The previous owner handled it very carefully and I do all repairs and maintenance as soon as they need to be done. He gets regular oil changes every 5000 km and only good Motul oil.

I have my own workshop with two lifts and I also repair automatic transmissions and have already overhaul some engines. However, everything is private, not commercial, and generally German cars, some of which are incredibly complicated to repair. The newer German engines are, the more terrible they are. Everything is just over engineered, throwaway products.

I've actually been secretly looking forward to working on the LS engine, which I've become very fond of because of its ingenious simplicity.

The idea with the valve covers is very good, I wanted to do a compression test in the near future anyway, take a look into the cylinders with the camera, so it's not such a big problem to remove the cylinder head covers and take a look.

However, I recently took off the oil pan to swap the O-ring for the oil pump and had previously poured a liter of diesel into the engine oil to dissolve carbon.

The oil pan actually looked pretty good. I think that the valve train is probably not completely carbonized either.

I don't think either it's the valve guides, but rather the valve stem seals.

I recently did this on a BMW n42 engine. That was such a bad screw-up.

The valve stem seals on the LS engine are probably like a vacation in Hawaii...

 

[Mudsport96]

Well with your experience the stem seals should not be too difficult for you.

You can find videos on YouTube that explain how to do them. And I believe videos explaining how to check the baffle drains for the PCV in the valve covers. If you can't find good videos I can look tomorrow for you. It is currently almost 2100 hours here and I just got back from cutting down a Christmas tree and dragging it back to the Tahoe, loading it on the rack and getting it to the house. I am dead on my feet haha. So it is bedtime, if you have more questions or can't find a good video explaining the pcv issue, just ask and I or someone else can find one I'm sure.

 

[Mudsport96]

Ok so, you may need to translate this as I do not know how fluent you are in American English. ( I don't speak the Kings English since they called an Oreo a cream chocolate biscuit , so I call what I speak American English). Hahaha
Anyway, here is a video of a modification to help oil to drain from the baffle on that valve cover.
Valve cover oil drain modification

 

[nonickatall]

Ok so, you may need to translate this as I do not know how fluent you are in American English. ( I don't speak the Kings English since they called an Oreo a cream chocolate biscuit , so I call what I speak American English). Hahaha
Anyway, here is a video of a modification to help oil to drain from the baffle on that valve cover.
Valve cover oil drain modification

Thank you very much for your information. My American English is not to bad. I think I would be able to to order an Donut and a coffee by pointing at them.

No only joking i think my english is quite okay and with the help of Google translate in some cases, it works very good.

At the moment I have no time to look at my engine, because winter is coming and I have quite a lot of work in my normal job to do.

But when I have time i will check the compression ratio and the valve cover.

I watched it now and there was no oil thrown out while engine start.

 

[rockola1971]

AFter verifying no leaks at oil pan, oil coiler lines if equipped, oil pressure sender, etc then I would do the compression check and if it passes then I would definitely suspect the valve seals. They could have been replaced and not done correctly or yours are original and/or your valve guides are worn for whatever reason but you would think when the heads were "reworked" they recut valves, installed new guides and seals and then redecked heads.

 

[nonickatall]

AFter verifying no leaks at oil pan, oil coiler lines if equipped, oil pressure sender, etc then I would do the compression check and if it passes then I would definitely suspect the valve seals. They could have been replaced and not done correctly or yours are original and/or your valve guides are worn for whatever reason but you would think when the heads were "reworked" they recut valves, installed new guides and seals and then redecked heads.

No, my car has no external oil leaks, the engine, all differentials, steering and the break booster are dry.

The oil is definitely burned by the engine. And in my opinion it can only disappear in four places.

On the oilrings of the pistons, on the valve stem seals, on the PCV valve and at most a defective cylinder head gasket, if I see it correctly.

So I think you're right and it will be the valve stem seals.

I now want to buy a decent camera to look into the cylinders and then I will do a compression test, take a look at the combustion chambers from the inside, look at the baffle plate in the valve cover at the top and then I may decide to change the valve stem seals close.

I don't think it's that much of a problem with the engine.

As I said, I constantly see German engines, built by engineers who, for whatever reason, deeply hate mechanics.

And when you see how long their engines last, the customers obviously as well...

I never thought I'd say this, when I was 16 and in the US for the first time, I defended the German car manufacturers and told every American that we build the best cars in the world.

Today in Germany, we are apparently only moral world champions...

but I digress...

 

[Mudsport96]

No, my car has no external oil leaks, the engine, all differentials, steering and the break booster are dry.

The oil is definitely burned by the engine. And in my opinion it can only disappear in four places.

On the oilrings of the pistons, on the valve stem seals, on the PCV valve and at most a defective cylinder head gasket, if I see it correctly.

So I think you're right and it will be the valve stem seals.

I now want to buy a decent camera to look into the cylinders and then I will do a compression test, take a look at the combustion chambers from the inside, look at the baffle plate in the valve cover at the top and then I may decide to change the valve stem seals close.

I don't think it's that much of a problem with the engine.

I am curious on the compression results.
Also how often do you run a tank of fuel through the engine? Are you using primarily LPG? Or do you change back and fourth?