Coolant leak
 

I started having coolant leaks last week, took a look and it was coming out of the water outlet. Replaced it as it was broken... you'd think that the problem was solved... nope!

Now I'm losing about the same amount of coolant but I can't see an external leak. With the car running and filled with coolant, I would wait for the car to warmup and look underneath and not a drip... The oil looks okay and not milky... no smoke out of the pipe. The heater is working fine too. 20 minutes of driving and the tank would get empty... Can't figure out where my coolant is going. Could anyone help?

Leaking intake manifold? Your thermostat is stuck open? Head gasket? check em all

The replacement water outlet tends to fail too. I made a custom aluminum one that uses the entire surface on the head as a sealing surface instead of just a crappy o-ring.

But more than likely, your leak is coming from the plastic "quick-connect" behind the engine where a metal pipe from the water pump connects to a hose going to your heater core. That plastic piece can be broken, and you can put a new hose right over the metal pipe and hose clamp it.

Or lower hose, upper hose.

Or the metal bleeder pipe going into the side of the water outlet with its tiny little o-ring that fails.

Otherwise, possible head gasket. My oil looked fine and exhaust wasn't smokey either.



Umm.. the intake manifold holds air, not coolant.
Thermostat controls when fluid flows internally through the system, it doesn't play a part in external leaks (that I've ever seen).
Not likely unless there's overheating issues as well.


Also the coolant cap might be bad. (or tank cracked).

I'll go and try again to locate it but the leak isn't starting until I'm driving so I'll have to drive it around the block and then check.
There is no heating issue until the coolant gets low enough. If it's the head gasket, I'll have to say goodbye to the car... less than 120,000 KM and I have replaced the engine once and fixed almost everything there is to fix...:No:

I've had coolant leaks recently at the water outlet, the upper radiator hose (obvious though), and the quick connect at the back of the engine going to the pipe.

Interesting enough, it's all coming out of the overflow pipe! I had the car running for half an hour and no leak... the fluid level stays the same. I went around the block and came back and the tank was empty with a big dump under my overflow pipe. Bad reservoir cap???

Yep.......that's what it sounds like to me....

Sounds like that to me too. Once that pressure gets released, all the coolant wants to go there.. higher pressure to lower pressure...

Not to scare you but that's a sympton of when the head gasket goes, too. Excess pressure in the cooling system. Hopefully it's just something minor.

It was just the cap... fixed now... was very close to take it to the car auction and get rid of it. phew!

Hmm you just needed that little rubber ring that seals it? Cause that might be whats causing me to fill it every 3 days..
And the thermostat was a problem in my car... had to replace it so i would stop burning away all my coolant.. :S LIMG was what was wrong the first time when i was loosing coolant.

I replaced the whole cap... it wasn't keeping the overflow under pressure and everything was just being pushed out.

My problem with the water outlet was real.... it had two big cracks in it but then because I had to open and close the cap a few times before I had the outlet fixed, the cap became defective too.

I have an interesting problem with my coolant cap...the part that screws in to the reservoir has separated from the top part used to screw it in. Crazy...but it still seems to seal properly.

Yeah, get a new (GM, not parts store) one soon.

I went through 3-4 of those caps, they separate, then you can only get it off with pliers or a screwdriver, and it might explode. I had one break apart and the spring shot out, shrapnel went all over.

Good advice...I've been putting it off for awhile now.