Avanteone
NAXJA Forum User
- Location
- Auburn, WA
To some of you, this all may be general knowledge and you will just say, "DUH".... but after so many rigs overheated last year, I thought I'd post up some simple tips or things to check. The XJ's cooling system is only marginal in perfect operating condition on a stock rig. Add lifts, big heavy wheels, tires, bumpers, winches, etc. and they are even more prone to overheating. The long hard pulls up the forest service roads and even some of the hills on the trails make the Naches area hell in an XJ.
XJ's ('87+) have both a mechanical fan with thermal clutch, and an electric fan. The electric fan should come on using the fan switch any time the rig gets up to like 210*. It also should come on any time the a/c or defrost are switched on. Make sure that it comes on when running the a/c and that should confirm most of the system is functioning properly.
The mechanical fan clutch should be tight, not freewheel. When the engine is cold, grab the fan and spin it, it should spin but have some resistance, not just freewheel. If it does, replace the fan clutch. Also, the fan shroud is absolutely ESSENTIAL on XJ's. If you don't have a fan shroud, get one. They're like $20 brand new at the dealer.
Thermostat. Many people will try and patch an overheating problem and replace the factory 195* thermostat with a 170* or 180* unit. This can actually make things worse as it doesn't keep the coolant IN the radiator long enough to cool it back down. The best bet is sticking with the 195* thermostat.
Water Wetter. This is a product made by Redline (same guys that make the synthetic oils), that works AWESOME. Somehow it changes the chemical properties and eliminates the little tiny air bubbles that happen inside the radiator and cooling system. It's under $10 for a bottle, available at Schucks and most auto parts stores, and can easily drop coolant temperatures 10-15*.
John
XJ's ('87+) have both a mechanical fan with thermal clutch, and an electric fan. The electric fan should come on using the fan switch any time the rig gets up to like 210*. It also should come on any time the a/c or defrost are switched on. Make sure that it comes on when running the a/c and that should confirm most of the system is functioning properly.
The mechanical fan clutch should be tight, not freewheel. When the engine is cold, grab the fan and spin it, it should spin but have some resistance, not just freewheel. If it does, replace the fan clutch. Also, the fan shroud is absolutely ESSENTIAL on XJ's. If you don't have a fan shroud, get one. They're like $20 brand new at the dealer.
Thermostat. Many people will try and patch an overheating problem and replace the factory 195* thermostat with a 170* or 180* unit. This can actually make things worse as it doesn't keep the coolant IN the radiator long enough to cool it back down. The best bet is sticking with the 195* thermostat.
Water Wetter. This is a product made by Redline (same guys that make the synthetic oils), that works AWESOME. Somehow it changes the chemical properties and eliminates the little tiny air bubbles that happen inside the radiator and cooling system. It's under $10 for a bottle, available at Schucks and most auto parts stores, and can easily drop coolant temperatures 10-15*.
John