Hi, the past few weeks I have finally started driving my 2008 2.2 HHR for longer trips up to 30 minutes daily now, and I noticed I lost about a quart of oil in about 100 miles. I changed my timing chain and water pump about a year and a half ago, along with a remanufactured head (there was some piston/valve contact). I did a compression test last spring and the values were all right around 140psi, so it seemed okay. I have around 2000 miles on the car since the timing chain change.

I checked the radiator cap today and noticed that the coolant was brown. I have no issues with coolant temp, it is always at 178-190 when driving. The most recent fix I did was about 3 weeks ago when the oil pressure sensor was leaking oil. I replaced that and cleaned below the sensor with some brake cleaner on the block. I also recently just cleaned my throttle body a few days ago.

From other posts that I've read this seems to be either a bad head gasket, cracked block, or bad water pump.
Would another compression test along with a leak-down test help me diagnose the issue more?

 

Those tests will verify compression and if the rings are good, brown coolant could be from the transmission fluid cooler in the radiator has corroded, it could be the water pump , and or the head gasket.
what brand water pump did you use?
what brand head gasket?
did you use new head bolts or reuse the old ones?
preparation is key to install of new parts, was the head a rebuild or was yours rebuilt?

 

I used the cloyes timing kit that came with a water pump and an enginetech head gasket. The head bolts were new. The head was a rebuild with the cams already installed. The head gasket surface was cleaned too.

Here's a picture of the engine before the head was installed a year and a half ago (might've cleaned it a little more after the picture)

 

Are you sure it is oil not just crud? Oil in coolant is rare, the water is under higher pressure than the oil at places they could mingle.

 

Yes usually it’s coolant in the oil! Is there a milky residue under the oil fill cap?

 

Now that I'm thinking about it, it's probably rust in the coolant. I'll check it later today to see if it really looks milky but I remembered that it was a dark brown. I'm guessing the more driving I'm now doing is causing there to be more rust suspended? The coolant is new from when I did the timing chain service too. Is it possible for me to lose the 1 quart of oil from the longer drives evaporating water in the oil?

 

Check one at a time. You did use Dexcool 50/50 mix right, so that would be orange! It’s an aluminium block head and radiator, so shouldn’t be any rust!

 

178F is too low, should stay above 180F.

 

I only see it go to 176-178 at high speeds when it's cold out (around 20 and lower), is this normal?


There is sludge on the oil cap. I've always seen it there even before I did the timing chains, there was some built-up under the valve cover too. It's yellow and usually has water around it, so I assumed it was just from driving such short distances (only around 5-minute drives usually).
I used dexcool 50/50, yep it was orange.

I just checked the coolant with a paper towel and it actually is still orange. I guess there's just some crud in there to make it appear darker than normal. There's no issue with the coolant most likely then, just wondering where the oil went.

 

Check the hose from the valve cover to the elbow at the throttle body, sometimes oil can get sucked through there during low rpm, the moisture is most likely just condensation, I had that problem in my 2007 2.2 LS . A treatment of Marvel Mystery oil and it cleared up. I added 1/4 quart to the oil with 50 % oil life left then changed oil and filter at 20 % oil life.