Moisture out exhaust pipe-How to find source?

850man · Post by **850man** » 11 May 2010, 01:22

Bought a used engine w/94K miles to replace overheated (warped) head on a resurrected 96 850 Turbo. I also replaced the radiator. After 10 min of idling, condensation comes out exhaust. Feels wet like steam. Engine runs strong, turbo smooth and quiet. After 25-30 min of driving, engine "recorrects"; it sounds like O2S or computer trying to correct a mixture problem, idle gets rough then engine cuts out if idle speed isn't increased. I put a bottle of Bar's in the cooling system and less condensation came out exhaust.
-Compression test: all cyinders 175-180. Could it be head gasket problem in spite of even compression readings?
-Chemical test confirmed exhaust in cooling system.
-Used a boroscope to look into each cylinder. Did not see anything strange, no deposits on piston domes, no carbon. Plugs are clean.
-no coolant in oil, no oil in coolant

**Is there any other way besides a head gasket leak or crack in head that exhaust gas can get into cooling system? Can turbo cooling lines be source of coolant into exhaust via wastegate? Is it possible gas from turbo wastegate can get through turbo and into turbo cooling lines? I am going to pull head this weekend. Any suggestions would be appreciated. Thanks!

Someone suggested re-torquing the head bolts a 1/4 turn. I am hesitant to do that wth torque-to-yield bolts. Is that safe?
I might as well lift the head and check it out at that point. Is there another diagnostic I can do to determine a crack in head? BTW no water in oil, no oil in water.

If I remove head and don't see obvious signs of gasket damage, what else should be checked?

Post by **JDS60R** » 11 May 2010, 07:30

Unless the center section of the turbo has a crack that allows coolant into the exhaust ( 1 in a million) you have a head gasket leak. 99.9% sure its a head gasket if the combustion gas test is positive.

If you just bought the used engine have the seller get you a new/er one. Offer them the combustion gas test result. If not, its time to pull the head and check the head and block for warp. Do not scrape the gasket. Use chemical remover and do not scratch the gasket surfaces - they need to be very smooth for this car. Steel wool or scotchbrite can do enough damage to cause an early head gasket failure. If the block is cracked down the midline then you must repalce the block. Over heating tends to crack it down the midline while overboosting tends to crack the cylinder on the front or back side. Please post a pic.

You can pressurize one cylinder at a time with a Leak Down tester or just remove the schrader valve from your compression tester and apply 100 psi through that tube. You will need an assistant to hold the crank pulley at roughly TDC for each cylinder.

Remove the rad cap and while the leaking cylinder is under pressure you will see bubbles in the coolant recovery tank .

Oddly enough a fair amount of these overheating failures is due to a bad radiator cap. Make sure to test it or replace it with a tested , new one. Beacuse of the design of the relief valves in our pressure cap the system does not like Bars leak. While Bars is a great product its particle size can be an issue with our caps working correctly. They make other brands that do not have the particles in case you have to have one. The system does not a sealant in normal use. Leaking hoses etc need to be fixed so the planned 22psi in the cooling system can be applied.

Please follow up with us.
We would love to know :
Which coolant you were using?
Did the rad cap hold 22psi?
Where was the damage allowing the leak?

Best Wishes,
John

Post by **jblackburn** » 11 May 2010, 07:37

Is there any other way besides a head gasket leak or crack in head that exhaust gas can get into cooling system?

No. Not on these engines. The turbos very rarely let those seals go, and you would be seeing more smoke than after just 10 minutes - that area warms up very quickly.

I'd say it's a fair guess that this engine overheated at some point in its life, and they buttoned it back up and sold it to you with a new head gasket when the head itself is warped. Once it warms up, the gasket lets loose as the block expands slightly around that warp and causes this to happen.

Try a compression test once it's warmed up to operating temp.

850man · Post by **850man** » 11 May 2010, 14:08

Thanks for the replies, guys. I will try the 100psi test. You said to do the 100psi test at TDC. Wouldn't it be better to find a block crack by doing it with piston all the way down the cylinder bore?

BTW, I talked to engine guy and he's is willing to swap me another engine. Seems like the right thing to do to avoid a "can of worms". I can swap the engine in less overall time than removing,analyzing and replacing the head. I will ask him to do a compression & hydrocarbon test on the new engine before sending. I'll keep you guys posted on progress. If they don't ask for old engine back, I will take it apart (when I get time) to find the root cause.

Thanks,
Mike

FCPEURO · Post by **FCPEURO** » 11 May 2010, 20:06

Glad you could get your hands on a better engine. This is the right thing to do. That engine you have right now sounds like it will be a bigger problem down the road.

Keep us posted on the new engine. Hope everything is smooth sailing from here.

850man · Post by **850man** » 09 Aug 2010, 23:50

Hi John & others,

I finally got to the root cause of my moisture in tailpipe problem. I went to local auto parts store and bought a $30 hydrocarbon test kit. It confirmed I had exhaust in my coolant. I pulled the head off and checked for warp , using a decent carpenter's level (milled prety flat). Using feeler gauges, I measured about 5mils of space, between 2nd and 3rd cylinder. Not trusting my measurement, I took it into a machine shop and had it measured. He confirmed 4-5 mils of warp. I had him remove valves and do a pressure test. The head was not cracked. I paid him to shave 4 mils off the head and install new valve stem seals. Put it together and voila no more steam out of exhaust! Thanks to all for your suggestions. BTW, the water level was still dropping -found a water leak leading to previous owner blowing the 1st head; the lower heater hose at firewall had a slight leak that dribbled down firewall. That's the next repair-to replace the heater hose coupler. Any ideas how to move the coupler over towards gas pedal and away form the evaporator casing (white plastic box) in order to remove with out having to tear dash apart?

Keith19851985 · Post by **Keith19851985** » 08 May 2018, 11:56

Hey mine is doing same thing except I had head off sent it to 2 machine shops both checked good but steam bellowing out exhaust I checked cylinder walls and everything looked good do blocks crack often I had no warpage in head