Small coolant leak coming from right side of engine (opposite of water pump/belt side). Doing strange things.

[sonicsprings]

Trying to decide if I should shell out the money to fix it. When I top off the coolant it will leak pretty heavily, but then once it leaks some out the leak will basically stop. The overflow tank has a tiny bit of coolant in it, if I put anymore in it it will inevitably leak out. So I just run the car on "semi-low" coolant and it doesn't leak anymore...

 

[rodslinger]

Did I just read the equivalent of my car has an oil leak so I stopped adding oil because it doesn't leak anymore when it runs out?

Find and fix the leak or be prepared for a new engine. Just clean the engine thoroughly and let it dry, add coolant and find where it is coming from. There is plenty of room to see especially with a small inspection mirror and a flashlight on these cars.

 

[sonicsprings]

Did I just read the equivalent of my car has an oil leak so I stopped adding oil because it doesn't leak anymore when it runs out?

Find and fix the leak or be prepared for a new engine. Just clean the engine thoroughly and let it dry, add coolant and find where it is coming from. There is plenty of room to see especially with a small inspection mirror and a flashlight on these cars.

No what I meant to say is that when the system is completely full about a little bit leaks out, but then after that the leak stops. So the coolant system has about 80-90% of the coolant it's supposed to have, and it isn't leaking.

 

[RayneFall]

Inspect the underside of your coolant reservoir tank. Mine was cracked / fractured just enough that it would hold coolant when cold, but would leak through the cracks when warmed up. I only discovered this because it would leak down onto the radiator hose, and the bottom of the coolant tank was wet.

 

[Bruiser350]

I agree with what Rayne is saying, but just go ahead and spend the $30 for a nee coolant reservoir just to rule that out as being the leaking part. The only other part on that side of the engine is the water outlet and a couple hoses....all are relatively cheap fixes.

 

[thelittlemugatu]

I've encountered the same issue - turns out mine leaks from the seam that's adjacent to the radiator side when it's filled to the proper level. And for me this happened less than 500 miles after replacing the the original recovery tank due to the aforementioned stress/temp cracks on the underside. So maybe that's where yours is leaking from too?

You know what they say, fool me once, fool me twice...so I'd recommend picking up one of the nicer aftermarket options. Probably going to pick up an aluminum one myself. To their credit though, the refund from GM was nice & easy. Not much to argue over I guess lol

 

[Z71]

I just fixed coolant leak on my Sonic. The leak was caused by worn gasket on the thermostat housing against the engine block. the coolant leak was substantial, as I saw a puddle under the car everytime I parked it. I replaced the entire thermostat housing as it comes fully assembled with temperature sensors and new thermostat and it is made of plastic so after 165k miles it was a good idea to replace it. No more coolant leaks after the repair. I used the OEM housing. I replaced the coolant overflow reservoir some time ago because as mentioned it was leaking slightly on the bottom.

So if your Sonic with the 1.8 liter engine has over 100k miles, be prepared to replace the oil cooler gaskets and thermostat housing gaskets because they will eventually leak, causing engine oil to mix with coolant (oil cooler leaky gaskets) and coolant loss (thermostat housing gasket).