The Hoyer Group's diesel carrier came to a halt on the northbound hard shoulder at junction 16 for Stoke-on-Trent at about midday but the rear later burst into flames.
The motorway has reopened with one northbound lane closure and there are delays, said North West Motorway Police.
The driver of the tanker was unharmed.
A Hoyer Group spokesman said: "A detailed investigation will be undertaken to establish the cause of the incident and any learnings."

The three Grade II-listed thatched houses at Silvergate caught fire late on Saturday afternoon.
Norfolk Fire and Rescue Service incident commander Simon Mason said crews may remain at the scene for a second night.
A National Trust spokeswoman thanked firefighters who "worked tirelessly".
Residents from two houses have gone to stay with family and friends, while the third family has been re-homed in a holiday cottage, the National Trust said.
"We do not know the cause or full extent of the fire yet but, most importantly, there have been no reports of any injuries and all of the tenants were able to get out of the cottages," said the trust's spokeswoman.
"We are enormously grateful to the crews who reached the cottages quickly, worked tirelessly to tackle the fire and have maintained a constant presence."
About 70 firefighters attended the blaze as it ripped through the roofs of the cottages.
"We expect to be on the scene for the remainder for the day and maybe over the night," said Mr Mason.
An investigation into the cause of the fire has been launched.

Premier, the maker of Mr Kipling cakes and Bisto gravy, this week revealed it had rejected two bids from McCormick.
McCormick said in a statement on Thursday that it was now "willing to consider increasing its latest offer".
Meanwhile Japanese noodle maker Nissin Foods has agreed to buy a 17.27% stake in Premier Foods.
Nissin, which Premier describes as a "long-term shareholder", is expected to take a seat on the Premier board.
McCormick, known for its Schwartz spices and Lawry's seasonings, first made a bid of 52p a share last month and then raised it to 60p a share on 14 March.
Premier rejected it "on the basis that it significantly undervalued the company and its prospects".
Now McCormick has said it may be prepared to increase its offer following "limited confirmatory due diligence", i.e. a review of Premier's pensions documentation, current trading and material contracts.
McCormick said "it would be an outstanding custodian for the Premier Foods brands and, can provide benefits for Premier Foods, its pensioners, creditors and other stakeholders, which Premier Foods' current capital structure cannot deliver."
Some shareholders are keen for Premier to seek a higher offer.
David Cumming, head of equities at Standard Life Investments, the fund arm of insurer Standard Life, which controls 7% of Premier, said: "Although we believe the 60p  bid indicated by McCormick is too low, we remain open to a bid at a higher level.
"We expect the Premier Foods Board, on behalf of its shareholders, to engage with McCormick and pursue this option to the full."
Premier shares have been on a roller coaster ride this week, soaring 50% on Wednesday following news of the McCormick bid, falling by more than 10% on Thursday on the announcement of the Nissin stake and then recouping nearly all their losses as McCormick said it might be prepared to pay more.
Premier used to be one of the UK's biggest food groups but came unstuck when it expanded too fast, loading itself with debt.
It has since sold off its Hovis bread business to the US-based Gores group, rebuilt its £20m production line at its Mr Kipling bakery in Barnsley and pushed through a £1.1bn refinancing package, which included a £353m rights issue.
It still owns a range of household UK brands such as Ambrosia rice pudding, Oxo stock cubes and Batchelors soups.
Premier is increasing its international operations following a recent co-operation deal with Nissin that allows Premier to distribute its products in the UK, while making its own products more widely available in key overseas markets.
Nissin invented the first instant noodles in 1958 and operates in 19 countries. Its products include Cup Noodles and Top Ramen.
A fuel tanker broke down and then caught fire forcing the closure of a stretch of the M6 in Staffordshire.
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Three families lost their homes when fire engulfed a row of National Trust cottages on the Blickling estate in Norfolk.
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McCormick, the American food flavourings business, has said it may increase its $700m (£494m) bid for the UK's Premier Foods.