I think my hot water tank is getting water out of the central heating system in it..? how is this possible only started about 5 days ago…I beleive this is happening because the water out of the hot tap smells oily like the water out of the radiators!
Unfortunately, you are the only one who knows how your sysem is connected and what is in it, unless you have a competent professional available. You should not be able to smell oil inside your heating system water or your drinking water. Have someone nearby who can examine your system and solve problem.
Hint for the future: When you call an automobile mechanic – letting him guess what kind of car you have while you ask about a noise under the car can raise prices. Everything in this world is fixed by model number, serial number and how it is connected.