Changing Iacv

cgaviator · July 1, 2009

I followed the instruction in the sticky post and cleaned the IACV on my daughters 99 RX300. Worked great for a few days now it's dropping low rpms and stalling again. I figured I'll just change the IACV this time at $280.00 for the part. Anything I need to watch out for, or can I just plug and play the old for the new?

code58 · July 2, 2009

I followed the instruction in the sticky post and cleaned the IACV on my daughters 99 RX300. Worked great for a few days now it's dropping low rpms and stalling again. I figured I'll just change the IACV this time at $280.00 for the part. Anything I need to watch out for, or can I just plug and play the old for the new?

CGA- How did you clean the IACV? Did you remove it and take it apart to clean it? There are those who get away with HA type of cleaning of the IACV. At least that's what I would call it- a lazy man's way of doing it. On the car and spray some cleaner in there and get results for a little while, hoping that it will work. You get the results back in proportion to the work that you put into it. I believe in doing things right the first time and not having to do it over, which means taking it off, apart, and cleaning it right. That means draining some of the coolant, since the coolant lines go through the IACV. If it worked for a little while, I can almost guarantee that if cleaned properly, it will continue to work.

As for replacing it, you can buy it online for about $200. As far as changing it, drain part of the coolant and to get the 2 Phillips screws off, use an impact driver (the kind you hit with a hammer) or a needle nose set of vise grips to get it loose. They are soft metal and most likely will strip before you get them loose. I used the old rubber seal (gasket) as it was in perfect condition and if you don't want to do that, must order a gasket because the IACV doesn't come with one. Good Luck in whatever you decide to do. By the way, I cleaned my DIL's and it worked perfectly, but because of a critical situation where the car was going to be 1200 mi. away for 6-8 mo., I chose to replace it to relieve stress on her.

cgaviator · July 2, 2009

Thanks - I did take it apart and drain the fluid, sprayed it out with the appropriate spray and nylon brushes, reassembled it and put it back together. The screws were a pain and I did strip 2 of them but got them out and replaced. the gasket seemed fine so I reused it also. I was just wondering when I replace it, if I need to recalibrate anything. Also, should I replace the IACV and throttle body or just IACV?

Thanks.

code58 · July 2, 2009

Thanks - I did take it apart and drain the fluid, sprayed it out with the appropriate spray and nylon brushes, reassembled it and put it back together. The screws were a pain and I did strip 2 of them but got them out and replaced. the gasket seemed fine so I reused it also. I was just wondering when I replace it, if I need to recalibrate anything. Also, should I replace the IACV and throttle body or just IACV?
Thanks.

CGA- Glad to hear you did it the right way- am still puzzled as to why it would work for a short while and then quit working if it was completely clean and free (no interference in motion) You did take the servo off when you cleaned it, right? It is such an incredibly simple device, other than dirt, it's hard to imagine why it would quit working after it had, when cleaned. I guess it's possible the electrical could go bad, but the coincidence is hard to comprehend.

If you replace with new, no calibration needed (or when cleaned). I don't know of a reason why you would have to replace the throttle body, unless you have reason to believe there is a problem with it. Is the car one that must be driven daily? If not, and you intend to replace the IACV anyway, I would suggest taking it back apart and seeing if the valve is completely free as it should be. I'm still puzzling over the success and then failure almost immediately. You might try plugging it back onto the lead once you get it off and have someone turn the key on and see if it responds the way it is supposed to, to make sure it isn't bad electrical contact. As a matter of fact, if you have some electrical contact cleaner and lube spray, I would pull the plug off and spray that in the plug and try "resetting" (insert and retract a couple or three times) and see if that makes any difference before you take anything apart. I have seen people spend a lot of money (and time) chasing electrical gremlins, when the solution is as simple as that. (previous sentence) Good Luck!

I checked my factory manual and it says: to inspect operation (with valve off but connected to plug) Have someone turn the key on while you watch operation of valve. In .5 second the valve should go from half open to fully closed, fully open and back to half open where it should have started. Be sure to do the plug "reset" and contact spray 1st.