'06 Aveo cranks, but won't start. Running out of options

[Tw1tcHy]

Well then.

Did an in line spark test all good. Did the compression test and, in order on each cylinder - 60 PSI, 55-60 PSI, 60 PSI, 80 PSI.

It was shortly after this that I rechecked the oil. It looked fine before, but after rechecking it and despite having looked fine before, the oil now looks like chocolate milk...

My instinct says head gasket naturally, but why does the oil look so poor after getting it running once?? When it DID run it ran fine, and how would this have taken compression out on ALL cylinders? We couldn't do the test with a warmed up engine of course, but no way it would have made a difference that huge...

The plot thickens

[slayerized6]

Stop overthinking it and bring it down to basics. You need fuel, air and spark for combustion.
-You have fuel pressure at the fuel rail
-You dont have anything preventing air from entering the cylinders
-You claim to have spark, on top of replacing wires and plugs
-You have compression on all cylinders

Some other things to think about
-Car has been sitting for 6 months. Its possible the fuel may just have gone bad?
-Even if you have a bad PCM, as long as you have fuel, air, and spark, you should have combustion
-Is the timing belt still in check?

[Tw1tcHy]

Agreed, that's how I've laid it out to her to help her understand the problems she's having. We 100% have spark and fuel, yet it struggles.

We have compression on all cylinders, but hardly. Seems to me that the lack of comoression would be a good indicator of why it struggles trying to fire up.

Turns out the car has o my been sitting since around early July, which changes the timeline a bit. Just discovered that last night, (she's bad with dates it seems...), so I don't think it's gas.

I will be checking the timing belt out very thoroughly later today. I'm not sure how to know if the #1 piston is at TDC with the head still on, or if that's even possible with this car, but I'll figure something out.

What's blowing my mind is that now all of a sudden this oil is classic chocolate milk, indicative of coolant mixing. But good God for the head gasket to have blown enough that there's a leak in every cylinder for the compression to be like this... Doesn't seem right.

[avguy]

Compression is WAY too low, and explains what you've been seeing. I'm guessing the coolant was low for quite a while, and she repeatedly cooked the head gasket (and likely warped the head as well). You could do a leak down test to confirm it, but I don't think that's necessary in this case.

[Tw1tcHy]

I didn't even bother with the leak down test lol. She swears she didn't drive the car much when it would begin to overheat, but I'm hoping like hell she didn't warp the head... If it's somehow miraculously just a gasket, then this should be good to go, but the fact that it's all 4 cylinders gives me doubts...

I began tearing into it yesterday. Only had 3ish hours or so, but I nerd to remove the coil pack and EGR mounts (easy), remove the bolts holding the intake to the head (fuel rail is already gone), and jack the car up on the front passenger side after removing the wheel to access the timing belt area and take everything off of that. That seems like the biggest pain in the ass left to do. Exhaust manifold is unbolted, I just need to get it off the studs.

This can't be over soon enough, but like I said, I'm seeing it through to the end! I feel like we're all in this together at this point haha

[avguy]

... but I'm hoping like hell she didn't warp the head...

Most of us DIYers don't have what's required to check for true, so you are going to take it to a machine shop, correct? It would be a major kick in the a$$ to reassemble, only to find it still has problems. Also plan on doing a couple of immediate oil changes, and a coolant flush, once it's back and running ok.

The one thing you need to cross your fingers (and toes) about is the effect of coolant dilution on prior lubrication of rings and bearings. The part about her running it for a while and getting worse over time sounds potentially ominous but, since there's nothing you can do about that, no sense in worrying about it.

[Tw1tcHy]

Absolutely. I used to build high end GM racing transmissions (4L80Es, TH400s, Powerglides, etc) for 1-2000hp clientele (even two guys in the show Street Outlaws) and if there's one thing the racing industry taught me, it's that a machinist and his equipment are worth their weight in gold (or at least billet aluminum).

We have a good place around here that's fairly cheap that I will be giving a call for an estimate. If their pricing is too out of line, then I will just have her buy a refurbished head.

The oil looked fairly good the first time I pulled the valve cover off and I added a couple of quarts of fresh oil after replacing the valve cover gasket and we got it to fire up that evening for a bit. I guess it was at that point that the oiled became extremely dirty, because it looked like **** when I took the valve cover off again a couple of days later. I don't know why it happened so suddenly, or what exactly triggered all of this. I have never seen anything like this before, and after some of the things I've encountered, an Aveo was the last thing I expected to hand my ass to me so bad haha!

[avguy]

Do you know when the timing belt was last changed on this Aveo? If she doesn't know, or if it's been anywhere close to 60K, you might want to have her consider buying a new timing belt kit. The 4 part kits go for around $100, and it's naturally a great opportunity to do that work. Of course that decision depends on her finances, and also how long she would like to keep it, assuming nothing else major happens.

Are you buying the gasket and head bolts from Chevy, or do you have another good source?

When you just dove into the engine disassembly with no hesitation, I had a hunch about you having some type of significant auto background. I hope this lady understands how fortunate she is to have you working on her vehicle!

[WyrTwister]

Forgive me , but how many miles on the engine ? If you send the head to a machine shop , you might as well ask them to see if it needs a valve / guides job . And , of course , if the head needs to be cut flat .

Yes , do the timing belt , coolant pump , and related parts , that comes in the kit .

Best of luck ,
Wyr
God bless

[Mcsquatch]

Could not find where to post a new Thread, Having starting Issues with my 2007 Aveo5. It Cranks but does not start, I was told to replace the Cam Sensor and the Crankshaft Sensor. Both of them I replaced, than I was told to replace the Alternator and to get a new battery which I did, and its still not turning over. After this I replaced the Spark Plugs, Coil Pack, and Spark Plug wires and still is not starting, I also replaced the 100 amp fuse which is attached to the Positive post on the Battery. All of the fuses are good, So Ive hit a wall and can not seem to figure this out.