Q: mystery radiator leak, put in Bars Alum stop leak, made a big difernce. on 1996 Buick Skylark

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still has noticable leak that rests in the frame well where the radiator sits, there are small wells and the coolent is there. Had a mechanic put on the pressure "thing" it showed no loss, but I don't know how long he had it on, or how long it HAS to be on before it reveals a loss of pressure. The radiator was replaced two years ago, spark plugs, wires, all hoses connected with the radiator, BUT DID not REPLACE the water pump OR the thermostat. How effective would be having a diagnostic dye put in? IF it is the water pump, OR the thermostat, would the diagnostic dye reveal THAT? I am having a cow
(1) Answer
first of all, stop leak was a bad idea. it cloggs the system. it may be masking the real leak. it would be temporary at best. the shop is doing the correct action but the stop leak has masked the issue. a dye will help but may take a while to show because the stop leak has to break down and allow the leak to show.
water pump is a common failure along with the intake manifold gaskets.