overheating
overheating
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
Could be any number of things. Could be as simple as bad sending unit, failed radiator cap, failed thermostat(yes even new, they fail), bad clutch fan, bad idiot dash gauge, failed water temp sender or a completely failed water pump. The overheat condition is broad in diagnosis.
Post back with info regarding; Year, Model, Motor, Mileage. Also, when was the last tune-up, general condition of vehicle helps in diagnosis.
Post back with info regarding; Year, Model, Motor, Mileage. Also, when was the last tune-up, general condition of vehicle helps in diagnosis.
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New User
Joined: Sep 2011
Posts: 5
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1992 f150.....4.9L.....mileage is about 150,000....water pump was new last year...(no obvious play in pump....no bearing noise or drag)...tuneup was about a year ago.....,,,where is the sending unit located.....and what is its function please..............
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
The sending unit is located on the passenger side of the block, to the back, and it's PITA to get really. I know I have to wiggle my arm up between the exhaust and the frame to get to it. It's function is for driver awareness as it doesn't send any input to the ECM, but to prevent Engine damage from overheating.
If you manage to find it and decide to replace it, I would drain some coolant from the system before doing so, as it will pour out until it's below the sender area. May also want to check for damage to the sender wire, could be be brittle or lose. Another diganosis, After you know the engine has completely cooled down, turn the key to Start. The pointer for the gauge should be on the cold mark. Now use a jumper wire and ground the sender wire. The needle for the dash gauge should be on or past the "HOT" mark. If it doesn't perform as noted, then the problem may be in the guage or wiring. If it does perform as noted, then the sending unit is defective.
Also do not leave the jumper wire connected any longer than it has to be.
If you manage to find it and decide to replace it, I would drain some coolant from the system before doing so, as it will pour out until it's below the sender area. May also want to check for damage to the sender wire, could be be brittle or lose. Another diganosis, After you know the engine has completely cooled down, turn the key to Start. The pointer for the gauge should be on the cold mark. Now use a jumper wire and ground the sender wire. The needle for the dash gauge should be on or past the "HOT" mark. If it doesn't perform as noted, then the problem may be in the guage or wiring. If it does perform as noted, then the sending unit is defective.
Also do not leave the jumper wire connected any longer than it has to be.
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