G35 overheat - ds radiator fan not working

[tollboothwilley]

How did you bleed the system?

This system is difficult to bleed.

I recommend jacking the front end up off the ground about as high as you can go. Start the car and let it run with the radiator cap OFF. It will spill and you will have to clean it up unless you use a spill proof filler on the radiator. Let the car run for a few min with this off, at a minimum until the car heats up to full operating temperature. Rev the engine a few times. Hold it at 3000 rpms for 10 sec. Let off the gas. Repeat 3 times. Turn the car off, keep the radiator cap off and let the car *burp* itself for at least an hour.

[flyhighusa]

I have never had a water pump impeller fail. However I have had the shaft seal fail and have seen this many times. This can be a source of air into the system. Keep in mind that if you get air into the system that it will blanket various parts of the system keeping water from coming in contact and carrying the heat away. You can actually have your coolant drop in temperature or increase. It may increase since the engine will get hotter and the coolant will then pick up more heat in the areas it does contact. It becomes sort of engine area contact area issue. The air will also displace the coolant. In much the same way as steam will make your coolant lever appear unnaturally high when in reality the system contains less water air will do the same thing and continue to do so until it is vented.

If concerned I would do as I suggested or use some other method of looking at coolant temperature so you may be able to associated it with what you know occurs. For example you know that your thermostat (at least if it is functioning correctly) starts to open at a certain temperature and is fully open at another. You know your fans start at a certain temperature and then shut down at another depending on their bandwidth.

What I have found out for example is that the thermostat on my car (stock) appears to start to open around 178 or so and will be fully open by 190. the reason I think this is true is that it will cycle between these termperatures up to the point the ambient is high enough that the termperature will then rise up to around 195 (ambient around 104). On my temp gauge this isn't all that much needle movement but easily viewable with the OBD gauge.

Perry

this describes exactly what's going on. unnatural high coolant level. have to bleed the system every time ( bled it with front end high for more than 3 hrs ) though I cannot detect any leaks would it be possible the shaft seal is shot and sucks in air but not blow out coolant?

it gets hot and all of a sudden it drops to normal temp range some times. ac kicks on and then off really quick.

is there a description how to tackle the replacement of the water pump? this would be HUGELY appreciated thanks so much for all the info this is actually fun.
Modified by flyhighusa at 11:27 PM 9/13/2009

[tollboothwilley]

You have air in your system.

You need to bleed it again. I could show you links to 1000 other people with this. If it jumps and falls quickly its from air in the system.

Bleed it again using the method I just described.

[flyhighusa]

Bled the system twice as you described. no change..,,,

I can let the car idle for 45 minutes and it keeps temperature. As soon as you start driving it 6-7 miles it starts to heat up quickly.

Trying the waterpump now. took it apart, but cant see anything wrong with it. also the rings look fine... still replace it?

have one more problem before i can put it back together though. http://forums.g35club.org/zerothread/451561

thanks a million!

[tollboothwilley]

Did you have the heat on the car all the way up to make sure that the heater core was burped out as well?

[flyhighusa]

had the back in a ditch and the front on a ramp trying to get it as high as I could. Maybe if I put a new pump in i'll let sears fill the radiator under pressure?

[tollboothwilley]

Did you account for the HEATER CORE?? you have to turn the climate control all the way up to 90* and full speed fan to really get air out of the heater core.

[Sentientbydesign]

I'm thinking the problem is a little more extreme than just air in the radiator.

What peaks my interest is the A/C issue. Does the A/C cut out as the car starts to heat up, or just while idling?

Also, your idle is too low. With the A/C on, it should idle around 800 rpm. 400 is too low.

[telcoman]

heat=evil

There are two kinds of heat.

The kind that ignites and burns down shanties

The kind that excites and brings down panties.

Sorry, i couldn't resist

Telcoman

[tollboothwilley]

How is the car doing now?

[flyhighusa]

Thank you all and especially tbwilly.

I pretty sure the problem is fixed. drove more then 100miles without a problem. the only time at slightly got over 90 degrees (not even a bar) is when I really kicked it 5k rpm and 115mph but as soon as i let the gas go it dropped below 90 degrees again. fans work again. brand new set. so did the following

- New radiator fan assembly (fixed old one, but already ordered unreturn. set)- Flushed radiator- New thermostat- New Waterpump (this was the kicker)

rebled the system after installing the waterpump (which was a *itch without proper tools)

she runs like new again.... love it. thanks a bunch

ps:

Regarding the timing chain tensioner. I molded my own plastic piece with a soldering iron and it seemed stronger then the stock piece (the one I lost)

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A/C runs like new again since replacing the water pump. My guess is the ECU kicks of the A/C as soon as it detects an overheat situation to attempt a cooldown. Pretty neat system if I may say.

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Also I removed the bumper today and undented a huge dent. Its not perfect but looks much much better. amazing what a blowdryer can do :-)

[rerodriguez2]

Hey flyhighusa i am having the same problem on my infiniti g35 replace thermostat radiator flush bleed the air many times and still overheats the water from radiator keeps going to the reservoir. I dont know what to replace anymore please help!!!