"BAR" stands for "barometric pressure", or 14.7 PSI. A 1.1 BAR cap would work out to about 16 pounds.
There are tests available to check for exhaust gas in the coolant, either with a dye, or a sniffer similar to a 4-gas exhaust analyzer. The presence of exhaust in the coolant indicates a crack or a head gasket leak. I've actually used my exhaust analyzer to draw a sample of air off the top of the coolant, looking for carbon monoxide or hydrocarbons, but it's a good way to ruin an expensive analyzer if any liquid gets drawn into the tube!
Jerry
