(Updates prices and re-leads)
* Stabilisation in oil price lifts energy stocks
* Auto stocks down as JP Morgan cuts China market forecasts
* European bourses in 2015: link.reuters.com/pap87v
* Asset performance in 2015: link.reuters.com/gap87v
By Sudip Kar-Gupta
LONDON, July 14 (Reuters) - European stocks turned positive on Tuesday as oil prices steadied and supported energy shares after initially tumbling on a landmark nuclear deal on Iran.
Investors' belief that Greece will pass reforms in order to get a new bailout also kept European stocks on course for a fifth day of gains, even though Greek Prime Minister Alexis Tsipras faces opposition over the austerity plan.
"There's been a lot of progress on Greece after the weekend, and that is one of the reasons why traders are continuing to buy into this market," said Thames Capital Markets strategist Nav Banwait.
The STOXX Europe Oil & Gas Index rose 0.7 percent, with Statoil the best performing stock in percentage terms on the pan-European FTSEurofirst 300 index, which was up by 0.3 percent.
German internet company United Internet also rose 2.4 percent after a price target upgrade from Deutsche Bank.
But carmakers fell as JP Morgan cut forecasts on China's auto market, a day after a profit warning from Brilliance China Automotive Holdings, which makes BMW cars in China.
JP Morgan also reduced its price target on Volkswagen , whose shares declined by 2.5 percent.
The FTSEurofirst is up around 15 percent since the start of 2015, while the euro zone's blue-chip Euro STOXX 50 index is up 14 percent.
($1 = 0.9059 euros)
Today's European research round-up (Additional reporting by Alistair Smout; Editing by Louise Ireland/Ruth Pitchford)