Questions about the engine cooling system?
General Cooling System Info
There are 2 types of Cooling systems on the XJ/MJ
- Open style - any normal cooling system used today.
- Closed style - no radiator cap and utilizes a pressure bottle. used in 87-90 XJs.
MAINTENANCE SCHEDULE
- Change engine coolant every 12,500 miles or 12 months.
- Thereafter change engine coolant at the beginning of every winter season.
- Maintain ethylene glycol and water solution at a mixture of 50/50.
Cooling System Specs
| Application |
Thermostat Temp F (C) |
Rad. Cap PSI |
Coolant Capacity Quarts (L) |
|---|---|---|---|
| 2.5L | 192-198 (89-92) | 12-15 | 10 (9.4) |
| 4.0L | 192-198 (89-92) | 12-15 | 12 (11.3) |
| 4.2L | 192-198 (89-92) | 12-15 | 10.5 (9.9) |
| 6.0L | 192-198 (89-92) | 12-15 |
14 (13.2) (1) - Without A/C 23 qts. (2.1L) for recovery tank. (2) - Includes 1 qt. (.9L) for recovery tank. |
Coolant Temperature Sensors
- the 99 XJ has only 1 coolant temp sensor which is located on the Thermostat Housing
Cooling System Upgrades and Tech Write-ups
- Replacing the Mechanical Fan with another OEM Aux Fan - External Write-up on NAXJA
- Replacing the Mechanical Fan with an Electric Aftermarket Fan - Writeup by Marcus
- Installing Dirtbound Offroad's 3 electric fan XJ kit