Exhaustgas detection in coolant

Hello there in the land of really bad head gaskets,

Does this happen often? I've never seen this tried, but you should be able to do this with a simple CO detector (try somebody like Mine Safety Apparatus).

If it is a "really bad head gasket" then isolation of leak through radiator would be difficult since any exhaust from exhaust manifold, valve cover etc would give a reading.

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In what way would exhaust gas from valve cover or exhaust manifold be found in coolant at radiator opening.

If there was a leak elsewhere it would be detectable throughout engine compartment including at the radiator.

Seriously?

I suspect it would be most effective to look for CO2, rather than CO. (Good quality combustion of hydrocarbons generates 10-12% carbon dioxide. Incomplete combustion creates carbon monoxide. (usually 1% or less).

WARNING: In my experience, engine radiators at operating temperature are pressurized to around 15 PSI. Opening the cap is likely to cause steam burns and coolant loss.

There is a test kit available at many auto-parts stores. If I remember correctly it cost somewhere in the neighbor hood of $35, and contains enough chemicals to do multiple test. The name on the one I have is Universal block tester. The kit contains a suction bulb and chemical changes color in the presence of combustion gases. It is available through test tools Inc. P.O. Box 14338 Portland, OR 97214. There's a second name on the box,combustion leak block tester. Stock number BT 500

Hi Yes Radiator shops use a great tool.It is callled..Universal Block tester.Made in the USA.the tester comes with a liquid product that goes from blue to yellow if there is gas in the cooling system.You do not say where you are but try www.uktools.com and put in block tester it will bring up the product.

good luck

If stopping and removing samples is not easy, the way we have used many times is to record coolant system pressure. This can easily be measured by any suitable gauge (electrical or mechanical) and monitored, obviously any leak of gas (or coolant) can be detected - allowing for pressure changes during normal operation.

How about using a radiator pressure tester? It comes with an air pump and gauge. Pressurize the radiator and see if the pressure decays. If the pressure does not hold you have a leak. Obviously this does not pin point a leak but it will confirm if one is present.

If you suspect an exhaust leak into the cooling system. The easiest and best way to check is to have a mechanic or if you have access to an engine diagnostics machine, take the "sniffer" for the tailpipe and hold it over the radiator filler with the cap off. The sensor will pick up any exhaust emmissions.

Hope that helps,

Exhaust gas is mainly water vapor, carbon dioxide, and nitrogen.

Carbon dioxide may be determined accurately by bubbling a known volume of air through a concentrated solution of potassium hydroxide (KOH) and measuring the amount of K2CO2 that precipitates.

Try replacing the radiator cap with one that has a pressure guage in it. the system pressure is normally 15PSI if it goes much over this the cylinders are pressurising the water. You can buy CO2 sensors from Jaycar or Dick Smith or Altronics or radio shack etc etc. They are quite common.

With hindsight- if the car engine is fitted with aluminium alloy cylinder head, this may pass all tests until warm- when the alloy expands just enough to let exhaust gas into coolant- this sudden pressure increase can blow the coolant out of the expansion bottle, plus the sudden increase in coolant temperature- I fit a coolant loss alarm to all my engines(my own make)- sited in the upper radiator hose- when the exhaust gas leaked, the alarm was sounding, stopping, sounding as the gas pressure blew coolant away from probe. The reason alloy heads warp are usually because of corrosion, which blocks the radiator tubes, which leads to overheating. If anyone wants to check corrosion rates, fill several beakers with : plain rain water- tap water- commercial radiator coolant- etc. In each beaker add a iron nail & a strip of aluminium- then monitor over several weeks/months- the only solution that shows corrosion is plain water/tap water!. I have heard that exhaust leaks into coolant system also leads to higher corrosion rates. I would think that a commercial testing kit would be a good investment, in the instance where one buys a second hand vehicle, with no knowledge of the fault above. I should add that the warp problem is worse with modern day vehicles with e-w engines, as there is less gasket/seal area between cyls/coolant ports.

There is a tool. You put some dye in a bubbler that goes in a special funnel over the rad cap. The dye is blue and if you have a leak it turns green.