Vehicle runs hot while idling
Sep 16, 2026 at 9:33 AM
Intermittent over heating?
JAMES FARNSLEY
- MEMBER
- 2 POSTS
What to check next
Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.
The nonworking fan is the first issue to resolve. With the engine cold, check coolant level using the vehicle procedure. Avoid further driving if it overheats, and never open a hot cooling system. Have a technician verify the replacement fan's application, connector condition, loaded power and ground, and the control command using the correct wiring diagram. A relay bypass that produced no movement does not identify the failed part unless the circuit and test connections were verified. Keep hands clear: an electric fan can start unexpectedly. If the correct supply and control reach the fan but it does not operate, the fan assembly needs investigation. If they do not, repair the demonstrated feed, ground or control fault. Then verify temperature at idle and normal fan operation. Investigate radiator flow only if the remaining evidence supports it. This sequence addresses the known fault before another major part is purchased.
Guidance references and applicability
HELLA: Radiator fans https://www.hella.com/techworld/us/passenger-car-parts/thermal-management/radiator-fans/ General reference linking overheating and absent fan operation to the fan or its electrical controls. Exact wiring, activation conditions and test limits must come from the vehicle's service information.
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Ok you say its intermittent when it overheats ..so when it starts to over heat does it happen abruptly all of the sudden or does it slowly creep up to it t ? And also does it go up and just stay hot or when the car starts moving down the road does it cool back down ?
If it cools back down does it do it quickly or does it take a long time to cool back down ?
If it cools back down does it do it quickly or does it take a long time to cool back down ?
Sep 16, 2026 at 11:19 AM
It slowly creeps up while idling to the third line on the gauge. It will quickly drop back down when start driving again. I've checked the relays (all 3) and the fuses.the old fan burned out. Replaced it and still no fan spin up. Bypassed relay an still no spin up.
Sep 16, 2026 at 12:12 PM
Sou ds like maybe your radiator is clogged to some degree theyr pretty cheap nowadays might be a good timento change it if its found to be bad also I believe on the model the transmission line runs through the radiator too when the radiator stops circulating efficiently it will creep up like that becuase the transmission oil running through it is carry hot and it acually heat the coolant inside the radiator instead of the radiator cooling the trans oil...and if it goes on for long enough it damages the engine and transmission..so i would look into it also one of the things the couses scale and grime to build up in the radiator is when people add water to it instead of coolant that really bad for the cooling system and all of its components
Sep 16, 2026 at 6:03 PM
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Discussion summary
Intermittent over heating?
The owner reported temperature rising at idle and dropping after the vehicle began moving. The original fan reportedly burned out, and a replacement still did not run despite fuse, relay and bypass checks. A contributor suggested a restricted radiator, but no restriction test or repair result was reported.
Reported outcome: The replacement fan remained inoperative. No confirmed diagnosis or successful repair was reported.
The bypass method, measured voltages and replacement-fan compatibility were not supplied. The discussion does not establish that the radiator is clogged.