[rjcarleton]

I am losing water from the system.Can see no visible leaks,pressure tested system..O.K.
Wired a bottle to the overflow hose to the ground,no water going out there.Have had a problem in the past with head gaskets,but i have no signs of that..no white smoke from the tailpipes..temp gauge steady..no water in oil pan...idle is smooth.Would not the pressure test on the radiator on the car have showed a head gasket leak?Is there a test that will show a definate head gasket leak?Oh yeah,there is no heater core leak either.This is a 455 in a 66 GTO...since a rebuild 2 years ago,i have replaced 2 head gaskets,so i am looking for that,but i don't see the signs of it.HELP!!!


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rjcarleton

[rjcarleton]

I am losing water from the system.Can see no visible leaks,pressure tested system..O.K.
Wired a bottle to the overflow hose to the ground,no water going out there.Have had a problem in the past with head gaskets,but i have no signs of that..no white smoke from the tailpipes..temp gauge steady..no water in oil pan...idle is smooth.Would not the pressure test on the radiator on the car have showed a head gasket leak?Is there a test that will show a definate head gasket leak?Oh yeah,there is no heater core leak either.This is a 455 in a 66 GTO...since a rebuild 2 years ago,i have replaced 2 head gaskets,so i am looking for that,but i don't see the signs of it.HELP!!!


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rjcarleton

[Ccass]

There is an inexpensive kit that you can buy at any parts store that tests your radiator fluid for oil. If there's oil...there's a problem.

[vaccaraj]

how much water are you loosing?
it is possible to loose it through the engine and not see the steam coming out of the tail-pipes. depends on the amount of water you're loosing.
if you've had a problem with head gaskets, you might want to check how straight the heads are. you might have to have them surfaced. this surfacing also gives a cross-hatch on the head which gives the gasket something to grab on to. this will allow the gasket to seal better. the block deck should also be checked. hopefully this is straight. hate to see you have to pull the engine.
sometimes you can see small bubbles in the radiator(with the engine running) if the head gasket is bad. i believe there is a much better test thats done on new cars today. something with dye and a uv light.
hope this helps somewhat.
tony

[mike nixon]

have you tested the hot and cold? i've seen cracked heads leak hot and not cold[first minute or two of operation].
if you change the head gaskets use felpro gaskets and coat them with halomar [spelling?] , it's a gasket coating by permatex made to take up imperfections in the sealing surface. mike

[KS circutguy]

I have been able to find unknown leaks this way...

Find a shop that has a 4 gas emissions analyzer,have them do a sniff of the coolant while motor is running and fill cap is open.

Ya dont want to submerge the probe,just hold it above the coolant and if theirs a leak,the 4 gas analyzer will see a rise in HC (hydrocarbons)which is unburned fuel.

This will confirm for sure that you have a leak in the head gaskets.Also;

Their is a kit you can buy at napa cheap that will test it.With a dye that changes from blue to yellow if theirs a leak..
I think its under $30.00 and its re- usable...Hope this helps..KS out. [img]/infopop/emoticons/icon_biggrin.gif[/img]

[rjcarleton]

O.K....heres an update...did a compresssion test...176-180 psi on all cylinders.Started out with overflow half full and radiator full.Drove 50 miles normal throttle,next morning,overflow is empty..radiator is full.Water is not escaping out overflow(i wired a bottle to the outlet of the overflow tank).NO water in oil..NO white smoke.The test kit to measure hydrocarbons at the radiator is $50.00 at Napa,and with those compression numbers,do i still need to do that test?Thanks for all the help guys,this one is driving me crazy!!!

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rjcarleton

[JC455]

Could it possibly be a small crack in the overflow bottle?


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John

[Blackcat]

I had an unknown water leak. Drove me crazy!
Turned out to be a freeze plug on the back of the block. When the engine was warm it would leak through the trans cover. Not easy to find.

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Gatomon
A car is cheaper than a girlfriend. Better than a wife. If it gives you trouble you can park it and forget about it!

[Richard Ohran]

Being from Texas, is there a chance that the weather is warm enough that you don't run antifreeze? If not, it could be leaking out your heater core in small enough amounts to avoid noticing - especially if you are running air conditioning.

[rjcarleton]

I actually scotched taped paper all over and under my overflow tank,there is no leak going on there.
The outlet and returns to the heater core are capped at the engine...so theres no heater core leak.
The freeze plug leak sounds possible,but when i pull into my garage after cruisin around,seems like even a small leak there would drip a little...there are no drips at all,and next morning,i check again underneath,still no water on the floor.
I am using about a quart(half an overflow bottle) in 50 miles of driving.
Thanks for help guys.


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rjcarleton

[Blackcat]

It only leaked when driving under pressure.
I never noticed any water. Only found out when the transmission was out! Try some Alumaseal and see if it helps.

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Gatomon
A car is cheaper than a girlfriend. Better than a wife. If it gives you trouble you can park it and forget about it!

[Michael G]

Try a 7# radiator cap. Less pressure on the system may temporarily solve the problem.

[rjcarleton]

Well,i broke down and bought the hydrocarbon vapor tester for the radiator at NAPA,and sure enough it tested positive for gas vapors,so i guess i do have a head gasket leak.I screwed up and did the compression test the other day when the engine was cold,and since have found out i should have done it on a warm engine,so maybe the small gasket leak only blows thru when the engine is warm and that is why the compression numbers were good.This will be the third head gasket replacement in less than three years,and yes we have used good Felpro gaskets...and the heads have been gone over by a good machine shop..any ideas what we should try this time?Thanks for all the help!

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rjcarleton

[llucas]

Install an aluminum cross-flow radiator and convert to Evans coolant. Non-aqueous polyethylene glycol and only atmospheric pressure in the cooling system.

[Ed Neasham]

OK, llucas, educate me. How does an aluminum cross-flow radiator and Evans coolant(Non-aqueous polyethylene glycol and only atmospheric pressure in the cooling system)
stop the leaking of headgaskets? It seems with 12 to 14 psi in the jacket the d/p (differential pressure) between the cylinder and the jacket would be less (albit only by a small amount) and therefore be less likely to leak.

Ed

[Herb Hagan]

Are you torqueing your head bolts properly?
Bringing them up to specified torque in steps, working from the center out?
What type of torque wrench is being used?
Has it been checked for calibration?
Condition/age of head bolts?
Just of few thoughts.
Herb

[llucas]

Ed Neasham, read the original post with these thoughts in mind. The recurrent head gasket failure can be caused by local hot spots in the heads, and Evans coolant will address and solve this problem. With atmospheric pressure in the cooling system, coolant won,t be getting into the cylinder during the intake stroke. Admittedly there are some things to be done to run Evans coolant, like blocking the thermostat bypass and installing an air bleed line from the top of the water pump impeller chamber to the vicinity of the water return neck on the manifold, but these things help the less-than-perfect Pontiac cooling system handle increased horsepower and heat load.

[mike nixon]

when you pull the heads again i'd check the block and heads to make sure that both are true. something has to be warped for you to have blown that many sets of gaskets. you also might want to have your torque wrench checked for proper calibration. mike

[Krosati]

rjcarleton
I'm glad to hear you found your problem. But it's too bad you have a gasket leak. I was going to suggest you watch the weep hole under the water pump neck.
I found a leak on my car after I was working on the fanblt one time. I pulled the belt around the fan to get it on the pulley and noticed there was water doplets on the belt. It took me a while but I found it.

Also, about a year ago, I was watching Shadetree mechanics and they demonstrated a dye that they put into the coolant system that shows leakes using a blacklight. Really helpful on newer cars with lots of junk in the way.
Krosati