Is it really 4.0 Qts, or is that a misprint in the online Owner’s Manual? It’s my father’s 3.5L. I was looking at it recently for another problem and in the midst of that pulled the dipstick (3 times) to see the oil level above the 4-dimples/cross-hatch area! I did the last oil change on it in December (car’s only been 900 miles since), and I’m thinking maybe I put 4.5 qts in it because that’s what I’ve been putting in my 2002 3.4L Impala for 18 years now (don’t remember checking the owner’s manual ... but maybe I did ... 4.0 qts seems odd to me now).

I looked in the manual for my 2007 Pontiac, which had the same engine (LZ4). It called for 4.0 quarts, too.

Typically, with the stock filter, the prescribed amount puts the level in the middle of the cross hatched area, at least that's how it works on my 2013 3.6. So a half quart extra should just bring it to the top of the cross hatched area.

If yours is much above the cross hatched area, you might want to drain a cup or two out.

The other consideration is that maybe coolant is leaking into the oil, bringing the level up. But, unlike the 3.4, this engine is not known for leaky intake gaskets. So it's not common for coolant to get in the oil.

To be sure, for ~20$, you can get your oil analyzed to see if there's any coolant in it. Test kits from Wix are available at OReilly's.

The “other problem” was a reported leak onto my sister’s driveway. The car was driven 20 miles and parked, allegedly leaking all over her driveway. I just idled the car (on ramps) for 20+ minutes, watching the fans cycle 2-3 times, and didn’t see any fluids dripping anywhere ... but there is a glistening on the bottom of the oil pan and signs of a possible coolant leak - but not from the intake gaskets or water pump ... all dry there. The plastic coolant tank looks low and the color is dark ... like oil. As it idled you could see some fluid coming back in but it barely covered the bottom of the tank! Maybe oil mixing with coolant??

The leaky thing on the LZ4 is the coolant cross-over pipe on the passenger end of the motor. The pipe runs between the heads, and connects to the ends of them. Replacing the gaskets at each end is the standard repair.

Coolant is less viscous than oil, and thus spreads more easily. It can run down the frame rail to create a larger spot. Plus, it gets on the serpentine belt which also spreads it.

You can borrow a pressure test kit at the auto parts store and use that to verify the leak.

[EDIT] One other thought, flip the oil dip stick over and measure it again. I find there will sometimes be a wet spot high and out of range on one side, but not the other. The actual level reading will be wet on both sides.

Doug

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Wow! OK ... less oil (i.e: 4.0 qts in a 2011 3.5l versus 4.5qts in a 2002 3.4L).

I did check both sides of the dipstick, too ... it was clearly past the dimpled/cross-hatched area (un-smeared) ... but that dipstick had some resistance going in, too. I was slightly twirling it with my left hand while applying pressure close to the inlet tube with my right hand in order to get it in there.

And I did check the serpentine belt for coolant (running and stopped) and it looked dry. I’ll take a look at that coolant crossover pipe you mentioned, but it really seems like it would be lower than that. The coolant pipes to the transmission might have been glistening, too ... it was hard to tell, but no dripping, so maybe from above that?

Maybe I’ll start with bleeding out some oil to get the dipstick right, then a drive to heat it up better. Maybe it needs a 20-30 minute drive to reveal the leak better?

 

Maybe I’ll start with bleeding out some oil to get the dipstick right, then a drive to heat it up better. Maybe it needs a 20-30 minute drive to reveal the leak better?

Chasing coolant leaks can be challenging. They can open or close with temperature.

Where I've had the best results is connecting the pressure test kit to the cooling system, starting the motor to get the engine up to temp, shutting it off, then adding a few more PSI with the pressure pump. Just a few, like 1 to 5 PSI.

If it is indeed a coolant leak, you should see some red/pink somewhere. But once the liquids get on the pavement, it can be hard to tell the color. So maybe find a white cardboard box, break it down to flatten it out, and put it under the car to try and catch any drips. Or maybe get a drip pan at Walmart or an auto parts store.

HTH.

Doug

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