So got my 09 ss turbo out Friday, while doing spring maintenance I checked out my coolant. The level looked good and I'm not due for a flush yet so I left it. 240km later I'm boosting up a steep hill when my low coolant warning gets tripped. I had been driving the car spiritedly off and on since getting it out and had no coolant issues, I even checked fluids twice before the issue and never notices a drop in my coolant.

I've since filled my coolant back up and driven it and still no signs of leakage, doesn't smell or look like I'm burning coolant. The car works fantastically really, I'm just worried since the coolant must have gone some where.

Is there anything I should look for? Some place coolant may be getting forced into under full boost? Does this sound like porous block? There's 150,000 km on this car so I figured the previous owners would have noticed and got the LDK already and I had no problems all last summer.

Any ideas?

 

Watch your coolant. How much did you put in? The coolant HAS to have gone somewhere. I spent quite a bit of money going to college so that they could tell me that matter is neither created nor destroyed without nuclear reactions It could have been a bubble or something. If it's porous block, it likely went into your oil. Unless you lose coolant overnight, you'd have to get the oil analyzed to know. Mine drained overnight into my oil pan. I opened the drain plug and got a bottle full of coolant. "Porous block" can strike at any time.

 

Who did u buy car from? 09 cobalt, missing coolant, sounds like the old porus block that so many 09s got hit with. Check ur oil if it's milky, if it is, u need a new motor more than likely.

 

I only needed to top it off with about half a cup- a cup of 50/50. My oil seems to be fine, did an oil change when it came out of storage, didn't see anything in it unusual but after the coolant disappeared I checked my oil cap, filter, dip stick and even drained a small amount from the pan to look for any discolouration and I'm not seeing anything at all. My 05 base cobalt has coolant getting into the oil so I've seen the yellowy white foam that it forms on the cap but I didn't see anything but clean fresh oil in this car.

I'm still not seeing a drop in coolant level now after a few days of driving so I'm hoping it was nothing but even after sitting for the winter my coolant level shouldn't have changed from what it was last year and when I did my initial inspection it was good so something must be going on.

Is porus block still covered by gm? How do I get my oil tested for leakage? I bought the car from a private sale from the original owners and they were the type of people who went to the dealer for every little thing so I can't imagine them over looking this. Can porous block really go unnoticed for that long?

 

If the coolant doesn't drop again you're probably fine.

"Porous block" is not covered by GM if you're outside of the powertrain warranty. Don't bother trying, they will just blame you. The porous block in the LNF is a little different than the classic definition. Most of the time a porous casting is noticed because the fluid slowly weeps through the metal. In our case, what seems to happen (or so I've read anecdotally) is that the porosity in the casting causes a crack which causes coolant to leak, usually into the oil pan. Because it's a fatigue issue, it can happen at any time. That's why if your car has it your previous owner may have never known. When I get some time I'm going to try and find my crack, cut it out, and see if my metallurgist friends will take a look at it in the microscope. It's taken me a while because life.

EDIT: I do remember my coolant dropping a little and setting off the low coolant warning a while ago. Then I had no problems for quite a while. Eventually, I got the warning again, filled it up, and then it was like it had an insatiable thirst after that. It even drained while sitting overnight. Was the initial drop in coolant a foreshadow of the porous block issue? No clue. The only thing you can do is enjoy your car and pay attention to the coolant level. If it cracks, then it cracks. Nothing you can do about it. No use letting it haunt you all the time like happens to some people even though it's unlikely there's going to be an issue.

Also, you can contact Blackstone Labs for the oil analysis.

 

Sounds like I'm going to have to hope for the best and see what happens down the road. Thanks for the info

 

i'd keep your coolant temp up on your DIC from now on and watch it like a hawk. ihad my engine replaced under warranty. i was lucky enough to catch it at the 110C mark before the engine grenaded. i had no coolant left in my engine when it was towed into the dealership. i had similiar experiences about a month before mine let go. may just be a fluke but better safe than sorry. wouldn't worry too much though. enjoy your car and if it happens it happens.. deal with it then!

 

good place to look for a leak that people usually don't think of is down by the line at the bottom of the reservoir, u pretty much have to take the fuse box off to see it right, but I had a leak there once, had to throw a zip tie on it together with the clamp.

 

Check for a leak
I had to add a small amount then about a month later a small amount then a month or so later found a crack in the radiator. Look everywhere even get a mirror it doesn't sound like your talking about very much fluid at all so the leak could be very small

 

I'm still hunting the leak, can't find anything yet. I'll be starting to pull parts for a better inspection if it happens again but unless something really starts leakin again it seems like it's so insignificant that I can't see it. Is it possible it's more so spraying out somewhere than just a leak? I'm just wondering if its not leaving much behind because its not even touching the car on the way out. I got the low coolant warning under full boost up a steep hill so maybe.

I'm still driving it exactly as I would before the leak, it's just hard to really enjoy it when I'm having to worry and watch my coolant temp all the time.

 

I am dealing with the same issues and have a thread,
https://www.cobaltss.net/forums/08-1...-again-316735/
my car started this at 120K miles and I have been fighting it for over 3K miles, I have done leak down test, compressions test, pressurized the coolant system, looked for leaks, steam, and smell and all tests show no problems, no apparent water in oil or moisture under oil fill cap and an oil sample has been sent to Blackstone Labs with no results yet.

 

Is is safe to say the porous block issue seems to rear its head when boosting over stock levels? I am having second thoughts on a 20psi tune because of this. Even if I am not "hard on it" a higher boost might still cause me issues, from the way it seems.

 

No, many unaltered tunes have the issue.

 

That yellowish stuff on your other cobalts oil cap is water mixing with oil (condensation). Its relatively normal on cars that arent driven far.

Your lnf-
on a Friday night, pull the spark plugs.
Fill your res and put a pressure tester on it.
Leave it pressurized over night.

If you are burning coolant there should be coolant in the combustion chamber in the morning.

Though... If its a porous block issue... It may only get into the chamber when the block is hot (the block expands a bit when hot).

So do the pressure test when the car is hot (with the plugs out).
Drive it for an hour or so to make sure it doesnt cool down too much, plugging your block heater in while doing the pressure test would be a good idea too.

 

Finally got a chance to do the pressure test as advised by random letters, thanks for the advice. Still nothing though, I haven't seen a drop in coolant again yet either which honestly has me more concerned since I'm still wondering where did my coolant go?

Six, I've been following your thread since before I had problems actually, you got the LDK right? Did that solve the problem?

I've done every test I could think of, everything advised by others in this thread and everything I can find on this site but haven't found any issues and the leak hasn't returned. I had plans for some modding this season but now I'm wondering if maybe I shouldn't if this is porous block. I was planning on a dp, K&N sri, tuned to 22 psi on stock turbo, Zzp larger front mount intercooler+ hot and cold side charge pipes.

So what do I do? Do I continue on with my plans or do I play it safe and see what happens? Should I be worried even after all the tests returned nothing? If I have porous block and need to swap it out I'm going with the LDK so it doesn't effect my upgrades anyway but I don't want to buy the parts and end up needing a new motor too.

I should also mention my oil sample was clear of coolant which makes me feel safe to bet I don't have porous block but I also changed the oil twice since the coolant disappeared so am i right to assume that may have effected the test?

 

I have my LDK on order, should be middle of next week, I am assuming you sent an oil sample to Blackstone Labs, and if so they ask what mileage is on your oil change to adjust their findings, I would go ahead and do whatever you want to your engine, from what I have read it doesn't much matter if stock or tuned for the porus block issue. My results from the lab didn't show any water in my oil but it showed a bunch of antifreeze, I guess the water burns off since I have a fairly long drive to and from work. Today is the first day I haven't driven my car, it was using about a quart of coolant per 60 miles , it seemed to get worst this past week. You will know when you have problems, you will add coolant about every day. I couldn't ran every test I could think of and my oil looked good to me but Blackstone found it.

 

I didn't get it done by blackstone, just took it to a local place and had them check it but my results show no water and no antifreeze. I told them the oil was pretty low km but the guy didn't seem to think that mattered, maybe I'll still send a sample off to black stone labs as well after I drive on this oil for a while. I'll for sure have it tested again if I have more go missing.

Good luck with yours man, I hope the LDK fixes it for you.