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Michael J.
Jedi Warrior
Offline
I had purchased a cast aluminum Thermostat housing for my 99 XJ8. Before I had time to install it, the plastic housing blew apart causing overheating. Although the resin of the housing looked alright on the outside, in the attached photo you can see the extent of the degradation on the inside. The failure was at the threads for the cap with the Allen Wrench hex.
Discussion threads that I have been reading talk about problems that the overheating can cause to the water pump since original water pumps use a plastic impeller and shroud whereas replacement pumps have aluminum impeller and shroud. After replacing the thermostat housing I experienced overheating even though the water level was correct in the header tank. The attached photo shows the failed thermostat housing and the problem that I found with the water pump. The replacement water pump is also shown as a comparison.
If you have not replaced the thermostat housing with cast aluminum, I stongly urge you to do so and avoid what I went through.
Discussion threads that I have been reading talk about problems that the overheating can cause to the water pump since original water pumps use a plastic impeller and shroud whereas replacement pumps have aluminum impeller and shroud. After replacing the thermostat housing I experienced overheating even though the water level was correct in the header tank. The attached photo shows the failed thermostat housing and the problem that I found with the water pump. The replacement water pump is also shown as a comparison.
If you have not replaced the thermostat housing with cast aluminum, I stongly urge you to do so and avoid what I went through.
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