[T20A02]

Hi, ever since I picked up my 08' TX wagon, I have been having issues with coolant use. When I say "use" I mean around a gallon every 100 miles. The car is basically un-driavable in this state and the only sign of a coolant leak is from behhind the coolant overfllow, pointed twards the driver side fender. Now this area gets wet, soo the first thing I did was check the overflow tank, and I saw a crack but was not sure it was leaking, so I replaced it just in case, still the same issue. It appears that the coolant is coming out of (this is an assumption) of the vent tube coming from up by the radiator cap. I then put the cap that is know good of another one of my cars on it in a pinch, and no change. I can hear a small amount of bubbling by the water pump outlet side of the car, and i have a gasket kit for the three gaskets over there, but I can visually confirm and its not super wet over there. What would cause the leak behind the res, and possibly out of that vent tube?? I fear a head-gasket as it misses a little at cold start but clears up. Planning on doing plugs soon, and if one is steam cleaned that will tell me if its the head gasket. Any ideas?

 

[Bob12312357]

Rent a radiator pressure tester kit. It won't test the cap nor the HG but at a gallon per 100 miles you should know if you have a HG leak from the smell alone.

 

[tannybrown]

Hi, ever since I picked up my 08' TX wagon, I have been having issues with coolant use. When I say "use" I mean around a gallon every 100 miles. The car is basically un-driavable in this state and the only sign of a coolant leak is from behhind the coolant overfllow, pointed twards the driver side fender. Now this area gets wet, soo the first thing I did was check the overflow tank, and I saw a crack but was not sure it was leaking, so I replaced it just in case, still the same issue. It appears that the coolant is coming out of (this is an assumption) of the vent tube coming from up by the radiator cap. I then put the cap that is know good of another one of my cars on it in a pinch, and no change. I can hear a small amount of bubbling by the water pump outlet side of the car, and i have a gasket kit for the three gaskets over there, but I can visually confirm and its not super wet over there. What would cause the leak behind the res, and possibly out of that vent tube?? I fear a head-gasket as it misses a little at cold start but clears up. Planning on doing plugs soon, and if one is steam cleaned that will tell me if its the head gasket. Any ideas?

Yeah I was fearing head gasket. Maybe an oil change will give you some clues (or just checking the dipstick?)

 

[T20A02]

I picked up an block test kit to see if there is exhaust fumes in the cooling system. Could it theoretically be the turbo? I'm not 100% how the coolant is routed but could seals fail and leak into the turbo, and burn them? ill post results on here of that test, and ill probably run a compression test.

 

[ReverendPaul]

That fume tester really is hit or miss. I don't think it does anything unless the coolant is already bubbling bad so it's sorta "no duh."

Yes, it could theoretically be the turbo and it would look like a head gasket either way they go (bubbling/ lots of smoke). Its not a common failure on a Saab (but failures are often kinda "not normal"). Still, it would 90% run like an absolute turd if the turbo was that messed up.

Milky oil is the one that can't be the turbo. Have you checked the oil? Top of the fill cap?

Compression tester MAY tell you if it's the head gasket (leakdown is the better test to see if it holds pressure/ would force out a leak to go were it's gonna go), but a headgasket can squeak by a compression test.

A vacuum gauge is the best one. Its basically a leakdown test (vacuum is the cylinder pressure) without having to yank plugs.

Cant rent it at autozone but if you buy used cars the vacuum gauge lets you test the engine completely in 5 minutes.

 

[T20A02]

I have checked the dipstick, and the cap and they both look normal. Today after hopping out of the car I am almost certain that the coolant loss is out of the vent. I'm going to run a block test, and a compression test after work, but other then a head-gasket what could cause over-pressure on the system? Could a thermostat failure cause boil-over?

 

[Bob12312357]

IMO start with a radiator pressure tester kit, then go do the rest. You are losing a ton of coolant, yet don't have smoke from the tailpipe, don't smell coolant from the exhaust pipe either, don't have cross contamination of fluids (coolant, oil, etc), don't have bubbling in the coolant system, etc, etc. I don't see the reason to chase zebras off the bat, Occam's Razor. . . . .

 

[T20A02]

Alright ill rent a Pressure tester kit tonight, and git it a whirl. I have a set of silicone d088 hoses ready for this car, was just hoping to wait a bit longer! Will update, and thank you all for the ideas.

 

[T20A02]

Unfortunately the block tester confirmed a failed headgasket, and with the removal of the plug on cylinder #4 I found a wet spark plug and a steam cleaned piston. Thankfully I have another motor on the shelf with less miles! Thank-you all for your input.

 

[jvanabra]

Ah, bummer, but at least you know the answer for sure.