Reader Question: Overheating Exasperation?

Here’s the latest reader question, along with my reply!

Don asks: I’m at my wit’s end with an overheating truck (2005 Tacoma). I have checked the radiator, replaced the coolant and water pump and thermostat. The engine still runs hot (according to the gauge) especially when pulling a hill. If you have any insights, I’d be grateful!

My reply: You didn’t mention it, so the first thing I’ll ask you is – are you sure the gauge is reading correctly?  Your engine may not be running hot. It may just be a bad gauge or sending unit. One easy way to check this without pulling parts is to get a digital infra-red thermometer – you know, the type they have been using as part of Sickness Kabuki at stores and gyms to take people’s temperature. You can use this to take the temperature of the engine/cooling system to see whether it jibes with what the gauge is saying. If not, you have found your problem, which isn’t overheating but an inaccurate reading.

Another thing I’d check right away – in addition to the temp – is whether the fan is working properly. If electric, is it coming on when it should? If mechanical, is the clutch working? This is the viscous-coupled device that bolts to the fan, that allows it to freewheel when appropriate but which engages the fan when more cooling is needed. With the engine off and cold, try to turn the fan blades by hand. Then try again with the engine hot  – engine off, of course. If you don’t notice a difference in play cold vs. hot (if the fan blades turn easily, regardless) then the clutch is probably bad and should be replaced.

I’m guessing one of these two things accounts for your problem. Check it out – and let us know!

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Got a question about cars, Libertarian politics – or anything else? Click on the “ask Eric” link and send ’em in! Or email me at [email protected] if the @!** “ask Eric” button doesn’t work!