A week ago I had a coolant leak. I discovered the turbo coolant return line was leaking. I was able to get my hand back there and visibly notice it. It was a small leak though. I replaced that hose this past Thursday. Last night my low coolant light came on. Indeed, my overflow tank was visibly empty. This hadn't happened when that hose was just leaking. I confirmed the hose is NOT leaking.

Putting the car up on ramps I see anti-freeze dripping. I took a picture as to the area, you can see the reddish drop of antifreeze getting ready to drip:



I'm not really certain WHERE this leak is coming from. It's leaking heavily though and enough of it to empty the overflow tank fairly quickly. Does anyone have any suggestions as to where this could be coming from? I have a good 3 hour drive tomorrow morning, I'll be stocking extra coolant and distilled water for the trip for now.

 

spray it off with a hose or brake cleaner or something.... blow it off or let it sit over night.... start it and get underneath and watch

 

This is a good idea. But before even getting to that point. What other coolant lines run back there? I've yet to do any real engine work on this car so I am not familiar with how the coolant lines are ran or how they work with the turbo.

From what it looks like the coolant feed comes from a distribution block on the left, runs under the turbo and then up and connects. The entire line is a hard line. Then just about where it connects in to the turbo is the return line. That comes up and around the top of the turbo then connecting to a rubber soft hose. Are there any other coolant lines? Is this only what I am dealing with?

 

knowing cobalts there probably a hole in the block or head somewhere, haha

 

Coolant feed goes to the rubber hose to the banjo bolt near the intake manifold. Coolant return routes down to the thermostat.

 

Thanks for clearing that up; I had them swapped. I won't be able to get under the car until Saturday to look at this. If I find the banjo bolt leaking, what would cause this? What else could I possibly expect to find?

 

Ya ur leak probably put air into the system making ur res suck dry. The lines arnt hard to fix when ur under the car. The feed line u should see looking down from the top of the motor in front of turbo, if that leaking ur manifold should have yellow stain on it. If not u get at the return line from under the car. Pretty easy

 

Mine was leaking, and it was due to the shitty banjo gaskets. I put new gaskets on and tightened them down, no more leaking.

The oil feed one is the worst one to get to.

 

Where did you find the gaskets? I'm having difficulty locating them. Perhaps I am using the wrong search terms?

 

GM dealer

 

Part number 12626102

 

Thanks guys, I picked the gaskets up and I'll be doing the install tomorrow or Sunday.

 

So I found something very interesting. I turns out the coolant return line was damaged and leaking. It's hard to tell from this picture, but there are two lines that look like it was cut with a dremel. The cuts are to the left of the aluminum covered flex pipe. The picture is very high resolution, but still taken with my phone. This is the pipe that is the lower connection on the turbo and runs to the coolant distribution block:



It was rubbing against the flange for the turbo and it cut right through. I smoothed the edge of the flange down a bit by hand with a file. I'll have to order a new pipe though.

Has anyone else seen anything like this happening? Why didn't GM design this to be 1/8th" further away from the flange? Are there perhaps tolerances between turbo castings from Borg Warner? This is frustrating, this should *not* have happened!

 

Btw, does anyone know what the torque spec is for the banjo bolts?

 

If no one puts the specs I'll do it when I'm off work, have Em at home

 

I want to say 17-19lb-ft. I'll check the exact number when I get home. There's a thread on some other forum somewhere out there on the internets with LNF torque specs but I can't find it at work. I saved it at home.

 

Thanks for the help guys! There's no rush. I had to special order the part and the dealer said it'll be here Wednesday or Thursday.

 

Just so that it's out there, I noticed that the oil gaskets are different than the coolant gaskets. So don't do what I did and buy 4 oil gaskets when you really need 2 oil and 2 coolant. Very doubtful you did something like that, but maybe helps someone in the future.

 

damn should of let me know. I had an extra since I switched my ZFR to all AN lines and fittings. Probably would of been cheaper.

 

I was actually considering doing this, but at this junction I have 3 vehicles and none are running. The Cobalt is the easiest to fix right now.

 

That was me 3 weeks ago. I know that feel.

 

If it still matters, coolant line bolts are 15 foot pounds

 

Thanks, it does. The part came in on Friday. I couldn't do it Friday night and it rained all day today. So I'll be doing this tomorrow.

 

I think this happened to me last night. I saw a small wet spot and just thought it was from the rain we had. I started to back up amd low coolant light flashed. I checked the engine nothing was leaking but the coolant tank was low. I looked underneath the car I saw leakage towards the back of the car around turbo area. I havent put it up on ramps yet. Thats my next step but I did see something like that aluminum pipe thing hanging and wet. Now that I see your pipe that could be my problem aswell. How much was the part and #. Let me know if its hard to fix.

 

I just installed the new part yesterday morning, filled the coolant back up, bled it and all is well now. Drove about 50 miles so far today and everything looks solid.

The part is easy to install, it took about 15 minutes to get the old one out and another 10-15 to get the new one in. I took some extra time to file down the edge of the flange that was rubbing; hopefully it'll help. The part was $90, I got it from a dealer so I didn't actually look up the part number. Thinking back, I don't think he gave me a receipt that may specify the part number. I'll double check when I get home this evening. It did take a long time for the dealer to get the part. I called it in Monday morning and they didn't receive it until Friday.

Thanks again for the torque specs guys!