| Oil and vinegar, maybe | 22 |
| Oil and water, e.g. | 19 |
| Oil and ___ | 11 |
| Oil apparatus | 13 |
| Oil apparatuses | 15 |
| Oil assessor? | 13 |
| Oil baron J. Paul | 17 |
| Oil baron, often | 16 |
| Oil barrel | 10 |
| Oil barrels | 11 |
| Oil bases | 9 |
| Oil baskets | 11 |
| Oil bigwig? | 11 |
| Oil billionaire | 15 |
| Oil blaze battler Red | 21 |
| Oil bloc | 8 |
| Oil burner | 10 |
| Oil burners | 11 |
| Oil buys | 8 |
| Oil by the barrel | 17 |
| Oil can abbr. | 13 |
| Oil can letters | 15 |
| Oil Can ___ ('80s Red Sox pitcher) | 38 |
| Oil can, maybe | 14 |
| Oil capital | 11 |
| Oil carrier | 11 |
| Oil cartel | 10 |
| Oil cartel briefly | 19 |
| Oil cartel for short | 21 |
| Oil cartel acronym | 18 |
| Oil cartel based in Vienna | 26 |
| Oil cartel initials | 19 |
| Oil cartel letters | 18 |
| Oil cartel since 1960 | 21 |
| Oil cartel's initials | 25 |
| Oil cartel's inits. | 23 |
| Oil cartel's letters | 24 |
| Oil cartel, for short | 21 |
| Oil centeer | 11 |
| Oil center | 10 |
| Oil center in Iran | 18 |
| Oil center in Okla. | 19 |
| Oil change | 10 |
| Oil change chain | 16 |
| Oil change go-with | 18 |
| Oil change unit | 15 |
| Oil city | 8 |
| Oil city of Iran | 16 |
| Oil city of west Texas | 22 |
| Oil city on the Caspian | 23 |
| Oil companies | 13 |
| Oil Company | 11 |
| Oil company acquired by BP | 26 |
| Oil company acronym | 19 |
| Oil company facility | 20 |
| Oil company founded by George H.W. Bush | 39 |
| Oil company founder Halliburton | 31 |
| Oil company headquartered in New York City | 42 |
| Oil company in a 1999 merger | 28 |
| Oil company machine | 19 |
| Oil company mercenary? | 22 |
| Oil company of old | 18 |
| Oil company sold to Texaco in 1984 | 34 |
| Oil company structure | 21 |
| Oil company that merged with BP | 31 |
| Oil company with a "trimark" logo | 43 |
| Oil company with a sign visible from Fenway Park | 48 |
| Oil company with a toy truck line | 33 |
| Oil company with annual toy trucks | 34 |
| Oil company's penchant for employee transfers? | 50 |
| Oil company, in Wall Street lingo | 33 |
| Oil conduit | 11 |
| Oil container | 13 |
| Oil container #1 | 16 |
| Oil container #2 | 16 |
| Oil container #3 | 16 |
| Oil container #4 | 16 |
| Oil containers | 14 |
| Oil containers ["Get down!"] | 38 |
| Oil conveyor | 12 |
| Oil corp. based in La Palma, Calif. | 35 |
| Oil corporation based in Irving, Texas | 38 |
| Oil country | 11 |
| Oil country: Var. | 17 |
| Oil deposit problem | 19 |
| Oil directly from a well | 24 |
| Oil driller's setup | 23 |
| Oil drilling device | 19 |
| Oil drilling equipment | 22 |
| Oil drum | 8 |
| Oil emirate | 11 |
| Oil encircler | 13 |
| Oil exportation grp. | 20 |
| Oil exporter | 12 |
| Oil exporters | 13 |
| Oil extractors | 14 |
| Oil facility | 12 |
| Oil family name of the '80s | 31 |
| Oil family of TV | 16 |
| Oil field investigation | 23 |