Strange leak from exhaust, is it coolant or something else?

[saber]

Hi guys

Got a bit of a weird one I’d like to run past you.

Recently I changed the water pump, radiator and thermostat on the old mans AU III Egas ute.
As I didn’t have any coolant on hand, I filled up with rain water (which had been filtered).
While checking for leaks, I found water (well what I thought was water) slowly dripping out of a hole in the exhaust (ie where the pipe first enters the muffler).

I thought “Damn, the old mans done his head gasket”.

After bleeding the cooling system, I took the ute for a drive. All was working well.

A week later, I was back working on the old mans ute; this time I was doing the transmission service.
After taking the car for a decent drive, I left the car running, and popped my head underneath to do one final inspection, checking for leaks around the transmission pan.

I then noticed there was still water dripping out of that hole in the exhaust. The thing is, the water was pretty cool, not even lukewarm.

I checked (and rechecked) that the car was at operating temp. The temp gauge was reading in the correct place (needle sitting at “O”), the thermo fans were both running, and the exhaust was hot to touch.

I haven't had a chance to run a compression test; that's next on the list.

Do you think this is still a coolant leak, or something else?

[Professor Farnsworth]

first step would be to put coolant in the header tank, which will answer the question pretty quickly.

[Rambunctious]

Cool water can come from the aircon drain and also the gas convertor.

[Kryton]

Originally Posted by Rambunctious

Cool water can come from the aircon drain and also the gas convertor.

Thats what it will be - aircon drain.

[saber]

Originally Posted by Professor Farnsworth

first step would be to put coolant in the header tank, which will answer the question pretty quickly.

Yeah there was coolant in the header tank; as far as I know, the level isn’t going down...

Originally Posted by Rambunctious

Cool water can come from the aircon drain and also the gas convertor.

Hi mate. Nah the leak isn’t coming from the converter or air con drain tube. The leak is coming from the exhaust, I saw it with my own eyes!

[BHDOGS]

Falling onto the exhaust somehwre then running down and dripping off?

[RSPEC#78]

its condensation mate. Every car will do it to a certain extent, depending on ambient temp

[Professor Farnsworth]

Originally Posted by saber

Yeah there was coolant in the header tank; as far as I know, the level isn’t going down...



Hi mate. Nah the leak isn’t coming from the converter or air con drain tube. The leak is coming from the exhaust, I saw it with my own eyes!

so you ended up putting proper green/red/whatever coolant in it? my point is you'd be able to tell from the colour if it were proper coolant.

[Torment47]

Originally Posted by davway

Thats what it will be - aircon drain.

I get drips from exhaust on my au and i don't use my air con.....

[Professor Farnsworth]

Originally Posted by Torment47

I get drips from exhaust on my au and i don't use my air con.....

condensation from the tail pipe is normal

[Torment47]

Hence why i agreed with respec#78

[saber]

Originally Posted by Professor Farnsworth

so you ended up putting proper green/red/whatever coolant in it? my point is you'd be able to tell from the colour if it were proper coolant.

Yeah 100% true.

As of yet I haven’t used proper coolant, only water. The reason being if the head gasket is gone, I’d have to drain the cooling system to remove the head (yes a dumb reason not to use coolant I know!!!)
But you’re 100% correct: If I did use the proper coolant, I’d know for certain if it’s a coolant leak or condensation.

Originally Posted by RSPEC#78

its condensation mate. Every car will do it to a certain extent, depending on ambient temp

Should condensation be forming if the engine is at operating temperature? I would have thought that the tailpipe would be so hot that any condensation within the tailpipe would have evaporated...

I mean, don't get me wrong...I'd be very happy if it was simply condensation, and not a blown head gasket...

[GasoLane]

I'm with the condensation crowd.

Try taking the car for a good 1/2 hour drive, then see if anything is coming out.

If it was anything serious like a head gasket there would be steam coming out of the exhaust and bubbles in the cooling system.

Trust me on this, I had a V12 Jag where the left tailpipe looked like a normal internal combustion engine and the right looked like a steam engine

[Mr Hardware]

Isn't that what the catalytic converter is there to do? Convert some of the noxious gases to (amongst other things), water?
Isn't that the main reason why exhaust systems 'wear out'? Because they rust from the water by-product from the process the catalytic converter undertakes?

[Kryton]

If you think its the head gasket leaking water (coolant) explain how the water comes out of the exhaust cold when the engine and exhaust is at operating temp.
Its most likely the aircon drain or condensation.

[Torment47]

Originally Posted by Mr Hardware

Isn't that what the catalytic converter is there to do? Convert some of the noxious gases to (amongst other things), water?
Isn't that the main reason why exhaust systems 'wear out'? Because they rust from the water by-product from the process the catalytic converter undertakes?

Well if that is the case that would explain why my muffler has a hole the size of a campbells soup tin.....

[saber]

Originally Posted by davway

If you think its the head gasket leaking water (coolant) explain how the water comes out of the exhaust cold when the engine and exhaust is at operating temp.

I can't, that's why I'm asking here

Its most likely the aircon drain or condensation.

I hope its condensate, and not the head gasket!

I found an interesting article on areas to check to determine if you’ve done a head gasket. I’ll definitely be checking the exhaust manifold this weekend!!!

http://autofix.com.au/blog/ef-el-hea...n-problem-area

[RSPEC#78]

the cat changes nox and carbon monoxide and other nasties to a more safe carbon dioxide. it can produce moisture but the moisture in your exhaust is from hot exhaust gases hitting the cooler exhuast pipe and cooler outside air temp, producing condensation. Nothing to be concerned about....

[RSPEC#78]

Besides, if you are really concerned about the head gasket. Get a "sniffer" test done on your cooling system. If theres a leak it will show up on the test. the test uses a tube with dye in it, which changes colour when exhaust gas is detected

[ronwest]

As has been said numerous times it's condensation. Every car I've ever had has done it.

[saber]

Thanks guys for all your help and suggestions.

I’ll do more testing (hopefully) on the weekend. Thinking of using proper coolant to see if the drips from the hole in the exhaust changes colour, a compression test, checked the exhaust manifold (as per the above link) and a head gasket testers (if the above 3 tests indicate a head gasket leak).

Hopefully it’s just condensation, and not a head gasket leak!

Anybody know where I can purchase a compression tester? Been meaning to buy one for a while, but unsure where to pick one up.

[ronwest]

Autopro, supercheap, Burson's, They'll all have them.

I think my new one cost me $40 from Autopro.

edit: Here you go... google is your friend http://www.supercheapauto.com.au/sea...ression+tester