This is the first time Ive heard of people pouring a solution into the engine oil to look for leaks, to Find oil leaks is pretty easy and should not require a solution IMHO, firstly you Identify what type of oil it is by smell or colour, ie transmission fluid, engine oil, brake fluid or even coolant. then you look for seepage or if no visible leak can be identified due to it be splashed over a large space of the engine bay/block you work down from the highest point of oil and going from there, any competent mechanic and DIY mechanics should not have a problem with identifying a leak no matter how small or big.
I have very little experience with American engines, just euro & jap engines, I also own a race car which coincidentally next week I'm fully rebuilding the engine and replacing 95% of the engine parts. CAP1 you know Volvo engines are the same as the ford engines in most of there cars, as ford own volvo. Over here people do not like American cars/engines that much either... So I think it mostly comes to what your use to etc.I don't like, Ford/Vauxhall/French/VAG engines that much like I said I love jap engines but thats mostly because thats where my experience is in.
I recomend you view this website and ask any questions as there are alot of Porsche specialists that will be able to offer you alot of advice,
http://www.pistonheads.com/gassing/
volvo engines may now be the same as ford engines, but that may not be the case.
the ford probe had mazda engines in it. the ford escort(later models)had mazda engines. the mazda protege(same as the escort) had mazda engines, but if i recall, as it's been awhile since i worked on one, they had ford EEC4 control systems.
the older volvos(the ugly box ones) that had the 2.3 turbo, was not a ford engine,,,,,,and a very dependable, and easy to repair vehicle.
the audi's i've worked on(which seem to me to be nothing more than overpriced volkswagens), have the same waterpump problems at the vw's.
some (real rocket scientist) engineer, decided to knurl the waterpump shaft, and press a plastic impeller onto it. how frakkin stupid is that??? these things fail by 50k miles(at least the ones in the US do). the volkswagens seem to have thermostat issues either just before, or just after the waterpump(although i replace the stat with the pump if i can convince the customer). if the stat fails first, it will normally stress the system juuuust enough to cause a failure on the waterpump.
the vw 2.3(i think) non turbo in the new beetle........this guy saw his idiot light come on, and continued driving for a few(after i pryed the info from him, it turned out a "few" was about 10) miles. popped the head gasket. it overheated, because the impeller came off the shaft on the waterpump. he said he didn't think it cold be that, because he had the pump done at the dealer at around 52k. it had 99k on it when i got it.
did the head gasket, took it for a test drive, and lost oil pressure. guess what????? vw put a PLASTIC
oil baffle in the rocker cover. it melted. they had a PLASTIC windage tray. it started to melt. the molten plastic blocked the oil pump pickup screen. real genius there.....
the few jag's i've worked on were mostly suspension work. the rear suspension(i think it was an xj12?) had such an over-complicated crappy rear suspension set-up, it was almost embarrassing.
saabs? you techs, and mechanics know what we all think of them. when one pulls in the parking lot......."eehh.......here comes another
sob story"
not comfortable to drive, not particularity powerful, not setting the world on fire with their handling....
mercedes........probably not really that bad, but i've yet to drive one thaT i like the feel of. they all smell like old furniture to me inside, and don't accelerate, handle, or stop the way i'd expect a top end european car to.
bmw.........i've driven quite a few that i really like, but they have their issued too. surge tanks that go bad, map controlled thermostats that go bad, on the older models, i've had a few bad bushings in the rear suspension. i've done a lot of balljoints in the front suspension. that seems like a poor design, although most bmw's i've driven handle exceptionally well.
so, with the experiences above, you can see why i don't much care for european cars.....and i've ALWAYS worked in general repair shops. i learned to fix anything that rolls into my bay. i've never worked at a dealer, and thankfully so, as most dealer techs i know, are lost when they need to work on something besides their make.
most asian cars i like. hondas and toyotas are frakking great cars. probably the absolute most dependable cars on the roads today.
most don't seem to like many american cars, but ford, chrysler, and gm ALL are producing much better cars than they're given credit for. they all have some very dependable cars.