Idle Air Control Valve lasts only three years

[John G]

Three years is about how long my idle air control valves are lasting. They've been the most frequent maintenance issue since I bought the ST new in 2000.



I just replaced mine for what must be the fourth or fifth time. I've got only 80k miles on the ST, as I drive it only for short 2-mile trips to work, mainly.



Symptoms are either:

* in cold weather, one morning, I can't start the ST -- it will crank but never start running.

* or it stalls while idling at a red light -- it just won't idle.



I've come to the point where I just keep a new one in the garage, ready for the next unexpected day when it won't start. It takes about four minutes to change it, once I've found a socket wrench with a 6 mm and 7 mm sockets.

 

[Todd Z]

I bet almost 100% you have the job 1 intake manifold gaskets going bad and not IAC valves.



the rubber o rings on the manifold half's and intake to head go bad on the job 1.



Have it tested or do the self tests.



Todd Z

 

[swshawaii]

Agree, seems that time affects intake gasket shrinkage more than mileage. Did you scan for trouble codes? Possibly p0171/174 lean codes? Never tried it but I've read blowing smoke through the brake booster hose with the engine off will help find intake leaks. Sounds much safer than spraying starting fluid around the intake with the engine running.

See posts #2 thru #9 in bottom link for upper and lower intake gasket repair.



2000StreetRod's Helpful thread list (4.0L SOHC)

http://www.explorerforum.com/forums/index.php?threads/2000streetrods-helpful-thread-list.263665/

 

[J Piroth]

Have you tried just taking the IAC off and cleaning it out thoroughly with carb cleaner? I only ask because I have a 2001 that has had IAC issues several times since I bought it in 2002, but each time those issues have been solved by taking the IAC off and spraying it out thoroughly, wiping it with a rag and getting in there with a q-tip as well.

 

[John G]

The stalling symptoms that I experience are completely and immediately fixed when I replace the IAC valve. So I don't think there's a reason to suspect the symptoms are explained completely by some other cause, such as leaks in the intake. But I am glad to learn about the intake manifold gasket anyway.



My check engine light never comes on, so I have not scanned for codes.



jpiro, yes I have tried cleaning the IAC as you describe. It is a cheaper solution, costing a few dollars for a can of cleaner as compared to about $56 for a replacement part. And it does work for a while. However, I found the problem recurred sooner after a cleaning than after replacement, and replacing is easier anyway, taking only about two minutes.

 

[Todd Z]

Maybe try sea foaming the intake, Cleaning the passages that feed the iac.... It sounds like they are dirty and causing the gook in there to damage the new iac.



Maybe get a set of pipe cleaners or something and clean the passages.



Todd Z

 

[Richard L]

My 2001 Job-1 IAC only lasted 2 months. Not dirty, just defective.



...Rich

 

[Yardsale]

I have the original IAC on my 2001. Almost replaced it, but it turned-out to be a bad injector. I have cleaned it maybe six or seven times. I lube the bushing shaft, but not the valve surfaces, with a drop of gun or similar oil.