Overheating Problems On Mystery Rig
Question: Well, first my water pump went out, so I replaced it. Then about a week later, my motor mount tore through its bolts and my motor fell into my radiator. After I put in a new radiator, it was running hot so I replaced my thermostat and thermostat housing, which broke during the repair. This still didn't make it run right, so I replaced my fan clutch, fearing it could have been broken in the fall. Still it won't run right.
The problem is: at idle, it heats up fast and runs very hot, but hasn't overheated yet, but when I bring it up to about 20 mph, it cools down to almost normal temperature and stays there until the next time I stop-then it heats up again. So I have replaced the radiator, water pump, thermostat, thermostat housing, a couple hoses, and the fan clutch, and it still runs hot. What should I look at fixing next? I'm out of ideas.
Tyler Jenner
via fourwheeler.com
Answer: The known facts are: The water pump, fan housing, thermostat, hoses, and radiator have been replaced.
It gets hot at idle.
It runs cool going down the road (better airflow through the radiator and more water-pump speed).
Unknown facts are: What is the vehicle? Some vehicles have more of an overheating problem than others.
Is something blocking the airflow through the radiator? Winch, lights, grilleguard?
Is the belt slipping, or is the clutch fan locking up? Look for signs of glazing on the belt. The clutch fan should be hard to turn by hand when it has heated up. (Naturally, with the engine stopped.)
Is there a fan shroud in place? Perhaps it was damaged when the fan went into the radiator. Without a shroud, the fan finds it easier to pull air from the sides instead of through the radiator. The fan blade tips should be about half in and half out of the shroud.
Condition of the engine: Does it have so many miles on it that it is ready for a rebuild? Did it overheat and possibly be damaged? Is there a restriction in the exhaust system such as a plugged catalytic converter, or smashed tailpipe?
Was the thermostat installed in the proper direction? The "pellet" end goes into the engine block. I have seen people install them backwards before with no end of heating problems.
Is something obstructing the airflow out of the engine compartment? See this month's "Willie's Workbench" for more on this.
Needs S.Y.E. Kit, But Can't Afford One
Question: I have a '90 Jeep Cherokee Limited 4.0L automatic. I recently purchased a 4 1/2-inch Rough Country lift. Everything I have read recommends a slip-yoke eliminator if you plan to do any wheelin', and I plan to do that every chance I get. Now the only problem is that I can't afford a slip-yoke eliminator. Is there another transfer case that does not have a slip-yoke that I could bolt up to it that could be found at a local junkyard? Or do you know of another low-cost solution to this problem?
Jordan Trompler
Kenmore, WA
Answer: Yes, most likely you're going to have to go to a slip-yoke eliminator kit, as a 4.5-inch lift puts the rear driveline at a just-marginal angle, as well as not quite enough slip-yoke engagement into the transfer case. The eliminator kit will give you more distance between the transfer-case output and the rearend for a longer driveshaft and will result in a better driveline angle. Then you can probably get rid of the spacers that came with the kit to lower the transfer case. This will put the front driveshaft angle back to where it is supposed to be.
There is not another transfer case you can swap to without some major expense. There are some NV231/241 Dodge combinations that use a flanged output, but these would require an input-shaft change along with new driveshafts.
The easiest solution is to do some trading for a 3-inch lift kit. Besides that, I feel that 4.5 inches of lift puts the front control arms at too steep an angle and destroys ride quality. Plus it transfers a lot more load when hitting a rock with a front tire into the arm's unibody mounting point.