Coolant coming out exhaust

[Scott Milligan]

Hi folks, lots off coolant coming out of exhaust. Not much smoke, mostly just liquid. I replaced both turbos when I installed the new used engine A few months back. No coolant appears to be in oil. Car still runs good, seems to make good power. Coolant level was low.

Im thinking one of the turbos are leaking coolant into the exhaust.

Anybody have an opinion on this?

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[NoSlo]

I had the same concern on my car 30 years ago when the tailpipe was dripping water, took it to our little-town mechanic, and he explained that the chemical product of gasoline+oxygen = carbon dioxide + water (plus the unclean byproducts).

Unless a drop of exhaust water tastes sweet like base coolant or tastes terrible from the bittering agent added in most states, I would think it's water vapor condensing in the tailpipe. Auto coolant is similar to smoke machine or vape pen liquid, so if it makes it into the cylinder or even into hot cats, it's going to be white smoke.

(also an overdue shoutout to that mechanic who diagnosed a pinhole leak in the diaphragm of the fuel pressure regulator on my Tempo, a part which has engine vacuum on one side and fuel on the other side of a rubber membrane).

 

[gwrabbit]

I had the same concern on my car 30 years ago when the tailpipe was dripping water, took it to our little-town mechanic, and he explained that the chemical product of gasoline+oxygen = carbon dioxide + water (plus the unclean byproducts).

Unless a drop of exhaust water tastes sweet like base coolant or tastes terrible from the bittering agent added in most states, I would think it's water vapor condensing in the tailpipe. Auto coolant is similar to smoke machine or vape pen liquid, so if it makes into the cylinder or even into hot cats, it's going to be white smoke.

(also an overdue shoutout to that mechanic who diagnosed a pinhole leak in the diaphragm of the fuel pressure regulator on my Tempo, a part which has engine vacuum on one side and fuel on the other side of a rubber membrane).

Great. Now we're going to have kids vaping Auto Coolant. Way to go.

 

[SHOdded]

I would agree with leaking turbo coolant feed lines.

 

[Johnbigdog]

You can run the car up to temp with a pressure tester installed, then pressurise the cooling system if necessary and let the car cold soak. If the water out the tail pipe is the color if the coolant you can remove an upstream O2 sensor or drop the exhaust to look at the turbos before removing them to see if there is a head or turbo failure.

Might be easier to pull the plugs and inspect each cylinder for coolant and rotate the engine by hand to see if there is coolant behind the vavles.

If you have clear water out the tail pipes, it's probably just a byproduct of combustion as noted above. You may not have bleed the cooling system as well as you thought when reassembling the engine.

 

[SM105K]

Great. Now we're going to have kids vaping Auto Coolant. Way to go.

Let them, natural selection will run it's course.

 

[gwrabbit]

Let them, natural selection will run it's course.

vape nation ya'll

 

[Scott Milligan]

You can run the car up to temp with a pressure tester installed, then pressurise the cooling system if necessary and let the car cold soak. If the water out the tail pipe is the color if the coolant you can remove an upstream O2 sensor or drop the exhaust to look at the turbos before removing them to see if there is a head or turbo failure.

Might be easier to pull the plugs and inspect each cylinder for coolant and rotate the engine by hand to see if there is coolant behind the vavles.

If you have clear water out the tail pipes, it's probably just a byproduct of combustion as noted above. You may not have bleed the cooling system as well as you thought when reassembling the engine.

I pulled exhaust union just aft of cars, ran car on lift and no water coming out of the pipes. The stuff coming out the tail pipes is black liquid. The car is tuned and runs rich. It has been near 80% humidity here lately. I've just never seen a car blast liquid out like this even with a bad head gasket. Both turbos are new oem so I think they are good based on looking at exhaust upstream.

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[SM105K]

I pulled exhaust union just aft of cars, ran car on lift and no water coming out of the pipes. The stuff coming out the tail pipes is black liquid. The car is tuned and runs rich. It has been near 80% humidity here lately. I've just never seen a car blast liquid out like this even with a bad head gasket. Both turbos are new oem so I think they are good based on looking at exhaust upstream.

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What tune?

 

[Johnbigdog]

I pulled exhaust union just aft of cars, ran car on lift and no water coming out of the pipes. The stuff coming out the tail pipes is black liquid. The car is tuned and runs rich. It has been near 80% humidity here lately. I've just never seen a car blast liquid out like this even with a bad head gasket. Both turbos are new oem so I think they are good based on looking at exhaust upstream.

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Sounds like you have normal water condensation coming out the exhaust from the catalysts working and condensation. Of the exhaust. If you have no water pouring out of the down pipes after the car cold soaks and starts back up with no smoke . No problems. The cooling system just didnt get filled completly.

 

[Scott Milligan]

What tune?

Sct tune, from unleashed I believe (it's my son's car and he did the tune)

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[Scott Milligan]

Sounds like you have normal water condensation coming out the exhaust from the catalysts working and condensation. Of the exhaust. If you have no water pouring out of the down pipes after the car cold soaks and starts back up with no smoke . No problems. The cooling system just didnt get filled completly.

Drove the car a bunch today, runs fine. The pin holes in the exhaust seemed to be plugged a bit. I cleared them and when the exhaust was hanging down in front while checking a bunch of water drained. The tune seems pretty rich, im thinking the water accumulated in there and was getting forced out. It was over 80% humidity the last few days here and it drops 30 degrees at night.

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[Majestic]

You have a coolant leak at one or both of the turbos.

 

[ridered74]

I've just never seen a car blast liquid out like this even with a bad head gasket.

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I had a 79 smokey and the bandit trans am that did that. If you let it idle in the garage there would be black spots all over the ground behind the exhaust. Being young and dumb I didn't think anything of it, motor seized not too long after that.

 

[shoblock]

Coolant level is easily checked. Mark the cold level with a felt marker and watch for variation over time (2-3 weeks). If the turbos are defective, one of them could send anti-freeze into the exhaust, but it would be rare from my experience. Usually, defective turbos leak oil on the ground or seize up.

 

[6500rpm]

Agreed with watch your coolant level and see if it drops. A coolant line to the turbo would be an external leak. I've never had one of these turbo's apart-is it even possible to pull coolant into the air stream or exhaust unless the housing's cracked? Oil yes, coolant I'm not sure.

 

[mrhighcaliber]

Agreed with watch your coolant level and see if it drops. A coolant line to the turbo would be an external leak. I've never had one of these turbo's apart-is it even possible to pull coolant into the air stream or exhaust unless the housing's cracked? Oil yes, coolant I'm not sure.

You're right. I've rebuilt several of these. The likelihood of an internal turbo coolant leak is extremely low. But More likely to dump in the oil passages within the turbo rotating assembly housing than into the exhaust. The casting is much thinner internally between the coolant and oil passages.

To the OP, Still have suspicions as to whether or not you have a coolant leak (head gasket)? Pull your spark plugs. Coolant tends to steam clean the combustion chambers. The cylinder's plugs with coolant leaks will have bright white porcelain and clean electrodes/ ground straps.

Im sure youve checked for milky oil, or rising oil level.

High humidity will increase exhaust condensation in addition to the water produced via the catalyst. If the exhaust steam smells sweet, youve got a leak.

Also, the aluminum banjo bolt gaskets on the turbos for coolant in/out will visibly leak externally. Hopefully they were replaced with the turbos, and torqued to 30ftlb. If you have access to a coolant pressure tester, connect and pressurize the system to 16-18psi (cap release pressure) for 30mins (cold engine!) Pressure may drop 1>psi (usually in the first 10min) due to the cooling system hoses expanding. Any thing more is suspect for a leak.

If you don't have access to the cooling system pressure tester. Jack up a cold vehicle, safely support on stands, and check the bottom of the turbo coolant lines and at the banjo bolts at the turbo for coolant leaks. Look for evidence of a white residue. Then start the vehicle and monitor the lines as the engine warms up. The coolant will evaporate off of the center housing of the turbo, but is usually slow. It usually will run down the lower line and drip.

Alwayyls use caution working around hot engine fluids and components.

Maybe this coolant mystery had already been solved, but this post should be beneficial to all.

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[twobitcoder]

I had the same concern on my car 30 years ago when the tailpipe was dripping water, took it to our little-town mechanic, and he explained that the chemical product of gasoline+oxygen = carbon dioxide + water (plus the unclean byproducts).

Unless a drop of exhaust water tastes sweet like base coolant or tastes terrible from the bittering agent added in most states, I would think it's water vapor condensing in the tailpipe. Auto coolant is similar to smoke machine or vape pen liquid, so if it makes it into the cylinder or even into hot cats, it's going to be white smoke.

(also an overdue shoutout to that mechanic who diagnosed a pinhole leak in the diaphragm of the fuel pressure regulator on my Tempo, a part which has engine vacuum on one side and fuel on the other side of a rubber membrane).

Do not ever taste liquid that might be coolant.

 

[NoSlo]

Do not ever taste liquid that might be coolant.

It's bittering agent you'll be tasting for quite a while, but otherwise the coolant is only toxic in "pets drink it" quantities, or a little bad for you because of the metal and exhaust products.

 

[Scott Milligan]

You're right. I've rebuilt several of these. The likelihood of an internal turbo coolant leak is extremely low. But More likely to dump in the oil passages within the turbo rotating assembly housing than into the exhaust. The casting is much thinner internally between the coolant and oil passages.

To the OP, Still have suspicions as to whether or not you have a coolant leak (head gasket)? Pull your spark plugs. Coolant tends to steam clean the combustion chambers. The cylinder's plugs with coolant leaks will have bright white porcelain and clean electrodes/ ground straps.

Im sure youve checked for milky oil, or rising oil level.

High humidity will increase exhaust condensation in addition to the water produced via the catalyst. If the exhaust steam smells sweet, youve got a leak.

Also, the aluminum banjo bolt gaskets on the turbos for coolant in/out will visibly leak externally. Hopefully they were replaced with the turbos, and torqued to 30ftlb. If you have access to a coolant pressure tester, connect and pressurize the system to 16-18psi (cap release pressure) for 30mins (cold engine!) Pressure may drop 1>psi (usually in the first 10min) due to the cooling system hoses expanding. Any thing more is suspect for a leak.

If you don't have access to the cooling system pressure tester. Jack up a cold vehicle, safely support on stands, and check the bottom of the turbo coolant lines and at the banjo bolts at the turbo for coolant leaks. Look for evidence of a white residue. Then start the vehicle and monitor the lines as the engine warms up. The coolant will evaporate off of the center housing of the turbo, but is usually slow. It usually will run down the lower line and drip.

Alwayyls use caution working around hot engine fluids and components.

Maybe this coolant mystery had already been solved, but this post should be beneficial to all.

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Update- car is running fine. It was a combination of not burping the cooling system after engine install and a few unusually humid days with large temp swings at night I believe. The drain holes in the exhaust were plugged, possibly from the previous failed engine which oil into exhaust.



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