We have installed a new shower, replacing an existing one. There was some new supply pipe installed to the shower head. When we turn on the water, hot or cold, we get a smell of petroleum, like oil or grease. The water has a slight film and a few small drops of what appears to be grease. Those drops smear upon touch. The plumber suggested we run the hot water for an extended period to remove any grease that may be in the pipe from the manufacturer, and we did, but the smell persists. It does improve sllightly the longer we let it run, but it is still too offensive to let people use it. The only plumbing that was done was to put a new supply line from the old tub faucet valve to the shower. In the old tub, there was a shower with a normal diverter and we never had any trouble like this . Nor do we have any other pipes or water supplies that give off this particular order. Any help with this?

Was the plumber who installed it the one who suggested grease in the line? If it's copper, then one of the things needed to put it together is called flux. It is a greasy and a bit foul smelling stuff that makes the solder work. He may have just used way too much of it.

I'd suggest cranking your hot water tank up to near high and try flushing it again. Let us know if that helps.

We are tying this approach and it does seem to be getting better. After about 2-3 minutes the smell decreases. Thanks so much.

Excellent. I'd go even 10-15 minutes of running on ultra hot just to give it a real good flushing.