Coolant leak in IACV-AAC

Hi,

I live in Taiwan and apologize for my poor English writing. Hopefully, I can describe my situation clearly and correctly.

Two months ago, I bought a used 2000 Nissan Maxima GLE in Taiwan which was the same model as those sold in the U.S. However, recently when I tried to clean IACV-AAC and throttle body, I found there is some coolant inside the IACV-AAC's auxiliary air passage and on the surface of it. I'm not sure if the leak is from the IACV-AAC or throttle body. The leak was small but I need to add some coolant every two week. I also found there were two in/out coolant hoses on the IACV-AAC. Can I just use a bypass hose to bypass the IACV-AAC? Will it cause any side effect? Will it effects warm up fast idle mechanism? In addition, if I decide to replace the defect parts, do I just need to replace IACV-AAC or both IACV-AAC and throttle body? I'm not sure if coolant will also goes inside the throttle body.

Any comment or advice is highly appreciated.

Thank you in advance.

Reply to
Eric
Loading thread data ...

I don't know car too much.

My 1991 maxima has bad coolent leak few weeks back causing the engine light on and power all off on the road. white smoke came out from the engine comparment.

It was a lossen hose that caused the leak. Good that the gasket was not broken or it would cost me lot of money to have it fixed. you pray that coolent is not leaked into the valves because it is not suppose to get into the valves unless something is broken within the engine part.

GL

Reply to
SmithChart

Thank you for your comment.

So far, the leak is small. It should not cause the engine overheat now. But, I need to keep my eyes on the temperature gauge from time to time during driving because the leak may get serious anytime.

I think the leak is in somewhere inside IACV-AAC or throttle body and those parts are not inside the engine and the amount of the leak coolant is small, so the coolant should be vaporized before it goes into the combustion chamber.

Maxima's parts are rare and expense in Taiwan. Nissan Taiwan only imported about one hundred Maxima in 2000 and 2001 and then stopped the sell. The dealer in Taiwan said both IACV-AAC and throttle body need to be replaced which will cost me a lot of money. I'm thinking using alternative way like bypassing the hose or only replacing the IACV-AAC to save some money.

Hopefully I can solve the problem soon and with minimum expense.

Reply to
Eric

You can probably rig a bypass. For some reason, Nissan had routed coolant through the throttle body. My guess is that it is to help the car deal with extremely cold weather drivability. A Maxima in Alaska would have very cold starts and the coolant flowing through the throttle body would help to get the IACV-AAC valve (which controls the way the car idles when it is cold) up to operating tempurature more quickly, and therefore work properly. Maybe running coolant through the throttle body also helps warm up the air coming in from the air filter. Either way, it's not a major function of the car if you remove it.

Since you're in Taiwain, you don't expereicne these tempurature extremes so you can bypass it. Get some extra hose and dis-connect the coolant hoses and put them together with the other extra hose.

CD

Reply to
Codifus

Thank you very much for your reply.

I read some discussions on the Internet about bypassing the coolant hoses on the IACV-AAC for performance reason. Some discussion also mentioned that the bypass may sped up carbon build up in throttle body or affected fast idle warm up mechanism. I don't worry too much about the carbon build up because I can clean the throttle body and IACV-AAC every 6 month. But, for fast idle mechanism, I'm not sure if idle speed will keep high after the car warm up once I bypass the hoses. I also checked the Nissan's Factory Service Manual and it didn't give me much answer for my question. However, if I decide to give it a try, I may need two hoses. One is for engine side for bypass the coolant. The other is for IACV-AAC to closing the leaky coolant passage which may cause a vacuum leak.

Reply to
Eric

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.