Joined
·
30 Posts
Rockkr4wl3r,
I have never seen this before, sorry! I will say however, that you have several issues here that are not necessarily related. So tackle them as different problems...
Your fan is an issue separate from the overheating issue, although still a problem. If the fan is constantly running (as long as the polarity is not reversed), this is not an overheating issue.
The radiator cap does have to be considered, since a properly operating radiator cap will relieve system pressure long before your radiator would crack. It is only rated at 15 PSI or so, and the radiator will handle quite a bit more pressure than that. So, although cap ay look fine it may still be defective, assuming system pressure is exceeding 15 PSI. If pressure is not the issue then radiators must have some sort of defect or the manner in which they are mounted to the frame is stressing the unit and causing failure.
Now back to system pressure! The system pressure should not get high enough to vent past the cap, particularly if the thermostat is functioning properly and circulating the fluid as it reaching the set temperature. So, does the upper radiator hose get hot once the coolant reaches it's set temperature? This will verify whether or not the thermostat is functioning properly.
Since the system functions fine at speed, your fluid is sufficiently cooling when there is increased flow. So this is normal... However, when there is reduced flow across the radiator you experience reduced cooling.
A few potential issues!
Now regarding the possibility of radiator clogging! Certain coolants will cause a gel to form in the cooling system that can eventually clog the heater core and radiator. Unfortunately, changing these units does not remedy the probem because the gel remains spread throughout the cooling system. I have changed both of these units before and have had the same clogging reoccur within one week. If this probem occurs, traditional system flushing does not clear the system. Flushing will exchange the fluid, but not usually the heavy solids.
How has your heat worked in the Winter? I started removing the heater hoses from the engine and forcing water through them from each direction to clear them. Works much better than the Prestone Flush Kit. This is much more difficult with the radiator however due to it's size and volume.
From Frank:
When did the previous owner change the heater core and radiator, and why? How many trouble free miles have you put on the Jeep?
P.S. I can tell when my thermostat opens because at 210* the needle drops 3/16" almost instantly...
Regards,
Carlos
I have never seen this before, sorry! I will say however, that you have several issues here that are not necessarily related. So tackle them as different problems...
Your fan is an issue separate from the overheating issue, although still a problem. If the fan is constantly running (as long as the polarity is not reversed), this is not an overheating issue.
The radiator cap does have to be considered, since a properly operating radiator cap will relieve system pressure long before your radiator would crack. It is only rated at 15 PSI or so, and the radiator will handle quite a bit more pressure than that. So, although cap ay look fine it may still be defective, assuming system pressure is exceeding 15 PSI. If pressure is not the issue then radiators must have some sort of defect or the manner in which they are mounted to the frame is stressing the unit and causing failure.
Now back to system pressure! The system pressure should not get high enough to vent past the cap, particularly if the thermostat is functioning properly and circulating the fluid as it reaching the set temperature. So, does the upper radiator hose get hot once the coolant reaches it's set temperature? This will verify whether or not the thermostat is functioning properly.
Since the system functions fine at speed, your fluid is sufficiently cooling when there is increased flow. So this is normal... However, when there is reduced flow across the radiator you experience reduced cooling.
A few potential issues!
- Water pump not cycling enough volume at low RPM (defective)
- Radiator not cooling a high enough volume of coolant as temp rises (clogging)
- Fan not pulling enough air across radiator to cool coolant (not the issue)
Now regarding the possibility of radiator clogging! Certain coolants will cause a gel to form in the cooling system that can eventually clog the heater core and radiator. Unfortunately, changing these units does not remedy the probem because the gel remains spread throughout the cooling system. I have changed both of these units before and have had the same clogging reoccur within one week. If this probem occurs, traditional system flushing does not clear the system. Flushing will exchange the fluid, but not usually the heavy solids.
How has your heat worked in the Winter? I started removing the heater hoses from the engine and forcing water through them from each direction to clear them. Works much better than the Prestone Flush Kit. This is much more difficult with the radiator however due to it's size and volume.
From Frank:
Do you notice any constant bubbling in the coolant with the Jeep running? If so, this could be signs of a head gasket problem...
When did the previous owner change the heater core and radiator, and why? How many trouble free miles have you put on the Jeep?
P.S. I can tell when my thermostat opens because at 210* the needle drops 3/16" almost instantly...
Regards,
Carlos
