High Idle Resolved!

Well, after posting on here a few times about a high idle issue on my '05 Trac it appears I have finally resolved it! This past weekend I was under the hood doing usual oil level checks, etcc, and I noticed that the coolant overflow bottle fluid level was higher than normal. Odd I thought. Then I opened the radiator cap and discovered the radiator was a little low. I am not getting any signs of the engine running hot, temp gauge is good, etc.. When looking in the overflow tank I noticed there was what looked like some slime. This lead me to check the overflow line, and at the radiator end of the line it was now completely stopped up. I assume before it got completely stopped up it was allowing fluid to escape, but then the radiator could not draw fluid back into it form the tank. I cleaned the line out, drained and cleaned the overflow tank, and put in new 50/50 coolant. The radiator and tank have now set themselves to their normal fluid levels and the truck is not experiencing high idle under any circumstances! I also ran a Forscan code check and there were no DTC's in the system. My theory is that the radiator was just low enough that the temp sensor was telling the truck to increase idle to get the fan running a little faster. If anyone has a better theory I accept it. I have driven it for 11 days now since I did this, checking fluid each day, and no issues. And the coolant tank is good and clean fluid.



Just thought I would share.

:banana::banana::banana::banana::banana:

Thanks Todd! The truck has not run this smooth in a while. Idle is dead on 750, with only a slight fluctuation as the a/c kicks on and off. I am still very pleased with the 'Trac. Mine only has around 123k miles on it, so it is just getting good and broken in. :grin:

LOL..... Here to many more !!



Todd Z

My theory is that the radiator was just low enough that the temp sensor was telling the truck to increase idle to get the fan running a little faster.

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This is exactly how Ford deals with high temp. condition. I had this with a faulty thermostat; caused funky shifting coming to stop.

Just a follow-up. It has been a good 6 weeks since I posted and I can happily say that the high idle issue is truly resolved! Who would have ever thought that a little bit of crud in the cooling system could stop up the coolant overflow line and cause this issue, but it makes total sense that this is what was causing the idle issue. We have been having ambient temps close to 100 with high humidity and the idle of my truck has been perfect! :supercool: