Many car manufacturers have specified 30-grade engine oils (5W-30 & 10W-30) for normal operation. Had multi-grade oils been available back in the 1930s and 1940s, they would have specified them rather than recommending seasonal changes with mono-grade oils. Where 10W-30 oils were originally specified, you may safely substitute 5W-30 or 0W-30 oils as these grades are only thinner than 10W-30 when the oil is cold.

0W-30 HDEO

• Chevron Delo 400 Synthetic 0W-30 (CG-4/SH)
• Citgo Citgard SynDurance 0W-30 (CH-4/SJ)
• Mobil Delvac Elite 222 0W-30 (CJ-4/SM)
• Petro-Canada UHP 0W-30 (CK-4/SN)

5W-30 HDEO

• Amsoil HDD 5W-30 (CI-4+/SL)
• Chevron Delo 400 LE Synthetic 5W-30 (CJ-4/SN)
• Mobil Delvac 1 LE 5W-30 (CJ-4/SN)
• Petro-Canada UHP 5W-30 (CJ-4/SN)
• Shell Rotella T6 Multi Vehicle 5W-30 (CK-4/SN)

10W-30 HDEO

• American Refining Group HDDEO SAE 10W-30 (CJ-4/SL)
• Amsoil ACD 10W-30/30 (CI-4+/SL)
• Brad Penn HDEO 10W-30 (CJ-4/SM)
• Chevron Delo 400 XLE Synblend 10W-30 (CK-4/SN)
• Chevron Delo 400 XLE Synblend ISOCLEAN Certified 10W-30 (CJ-4/SM)
• Chevron Delo 400 XLE Synblend 10W-30 (CJ-4/SM)
• Chevron Delo 400 ZFA Synblend 10W-30 (FA-4/SN)
• Citgo Citgard 600 10W-30 (CJ-4/SL)
• Citgo Mystic JT-8 Synthetic Blend 10W-30 (CJ-4/SN)
• Irving IDO Universal 10W-30 (CI-4+/SL)
• Irving IDO Synthetic Blend CJ-4 10W-30 (CJ-4/SN)
• Lubrication Engineers 8130 Monolec 10W-30 (CJ-4/SM)
• Mag 1 Fleet SAE 10W-30 (CH-4/SJ)
• Mobil Delvac 1300 Super 10W-30 (CJ-4/SM)
• Mobil Delvac Elite 10W-30 (CJ-4/SM)
• Mobil Delvac Super FE 10W-30 (FA-4/SN)
• Petro-Canada SHP 10W-30 (CK-4/SN)
• Renewable Lubricants Bio-Fleet HD Plus 10W-30 (CJ-4/SN)
• Shell Rotella T Triple Protection 10W-30 (CJ-4/SM)
• Shell Rotella T4 Triple Protection 10W-30  (CK-4/SN)
• Shell Rotella T5 10W-30 (CJ-4/SM)
• Shell Rotella T5 10W-30 (CK-4/SN)
• Shell Rotella T5 Ultra 10W-30 (FA-4/SN)
• Valvoline All-Fleet Plus 10W-30 (CJ-4/SM)

15W-30 HDEO

• Chevron Delo 400 SD ISOCLEAN Certified 15W-30 (CJ-4/SM)
• Chevron Delo 400 SD ISOCLEAN 15W-30 (CJ-4/SM)