Why generators show "high oil pressure": 14 documented causes and brand-specific fixes, compiled across 7 manufacturers.
Oil too heavy. Clogged oil passage. Oil relief valve stuck.
3 brands- Cummins/Onan: Drain, refill -with proper oil. Clean all lines and passages. Remove and clean.; Drain, refill with proper oil. Clean all lines and passages. Remove and clean.
- Garretson: Drain, refill with proper oil. Clean all lines and passages. Remove and clean.
- NEC: Drain, refill with proper oil. Clean all lines and passages. Remove and clean.
Oil too he:l.VY•
2 brands- Cummins/Onan: Drain, refill wit.h proper oil.
- Doosan: Drain, refill wit.h proper oil.
Improper oil classification, Oil pressure regulating valve bushing loose (wanders), Improperly operating regulating valve, Plugged piston spray jet, Stuck or damaged filter bypass valve, Stuck or damaged oil cooler bypass valve
2 brands- John Deere: Drain crankcase and refill with correct oil., Remove and inspect oil pressure regulating valve. See your John Deere engine distributor or servicing dealer., Remove and inspect oil pressure regulating valve. See your John Deere engine distributor or servicing dealer., Replace piston spray jet. See your John Deere engine distributor or servicing dealer., Remove and inspect filter bypass valve. See your John Deere engine distributor or servicing dealer., Remove and inspect oil cooler bypass valve. See your John Deere engine distributor or servicing dealer.
- Katolight: Drain crankcase and refill with correct oil., Remove and inspect oil pressure regulating valve. See your John Deere engine distributor or servicing dealer., Remove and inspect oil pressure regulating valve. See your John Deere engine distributor or servicing dealer., Replace piston spray jet. See your John Deere engine distributor or servicing dealer., Remove and inspect filter bypass valve. See your John Deere engine distributor or servicing dealer., Remove and inspect oil cooler bypass valve. See your John Deere engine distributor or servicing dealer.
Oil too heavy.
1 brand- Cummins/Onan: Drain, refill with proper oil.
Defective gage. Oi] too heavy grade. Clogged oil passages.
1 brand- Cummins/Onan: Replace. Drain. Refill. Cleanall lines & passage: Clean by-pass.
Oil too heavy grade.
1 brand- Cummins/Onan: Change oil.
Defective gage, Oil too thick, Clogged oil passages, Oil relief valve stuck
1 brand- Cummins/Onan: Replace, Drain. Refill, Clean all lines and passages, Clean by-pass. Replace if needed
Defective gage, Oil too heavy grade, Clogged oil passages, Oil relief valve stuck
1 brand- Cummins/Onan: Replace, Drain and refill with proper oil, Clean all lines & passages, Clean by-pass
Oil too heavy. Clogged oil passage. Dil relief valve stuck. Mefective oil pressure gauge.
1 brand- Cummins/Onan: Drain, refill with proper oil. Clean all lines and pas sages. Remove and cleaa. Replace.
Oil too heavy.; Clogged oil passage.; Oil relief valve stuck.; Defective oil pressure gauge.
1 brand- Cummins/Onan: Drain, refill with proper oil.; Clean all lines and passages.; Replace.; Replace.
Oil too heavy. Clogged oil passage. Oil relief valve stuck. Defective oil pressure gauge.
1 brand- Cummins/Onan: Drain, refill with proper oil. Clean all lines and passages. Remove and clean. Replace.
Oil too heavy; Clogged oil passage; Oil relief valve not eating
1 brand- Cummins/Onan: Inspect oil, Drain, refill with proper oil; No simple test, Return unit to depot for repairs; Remove and clean oil relief valve
Common questions
What causes high oil pressure?
Common causes, most-reported first: Oil too heavy. Clogged oil passage. Oil relief valve stuck.; Oil too he:l.VY•; Improper oil classification, Oil pressure regulating valve bushing loose (wanders), Improperly operating regulating valve, Plugged piston spray jet, Stuck or damaged filter bypass valve, Stuck or damaged oil cooler bypass valve; 4, 38, 41.; Oil too heavy.; Defective gage. Oi] too heavy grade. Clogged oil passages..