i just encountered the dreaded buzzer and add coolant light. my seven was parked for about a week while i was working on the rear brakes. got her back on the road last night and thats when it started. after reading through most of the threads about this issue i am hoping that i just have an air bubble in the radiator. however i dont know where that is. S4's have them on the right side of the radiator, correct? i have a 91 n/a, where could it be?

 

The don't have them.

The S4's needed them b/c the top was higher than the top rad hose, creating an air pocket in the radiator. Taking out that bleed screw got rid of the air in the top of the rad.

On S5's, there is a rad cap on the radiator itself, so there is no need for a bleed screw. The rad filler cap of the S5's is the high point of the system, so all the air bubbles travel to it.

 

so if the radiator doesnt have a way of traping the air, theh i definitely have something else going on...i.e. probably not good. would the color of the fluid in the overflow container be a sign of any particular problem? i am looking a a brownish color. maybe its getting rusty in there? BTW the buzzer/light only gone off after 5-10 minutes of driving, but the engine temp stays at 1/2. the warnings are intermittent and never consistent, some short some long.

 

To bleed the air out of an S5, you idle the engine with the rad cap off, for about 30 minutes.
Do this over some pavement to see if you have a leak from one of your hoses. Also, turn on your heat to see if it smells sweet.
Failing this, look into your rad cap while the car is running. If you are still seeing bubbles after the 30 minutes... budget an engine rebuild.

 

damn thats rough. the engine is only 81,000 new. i was hoping to get another 20 out of it before looking into something like that (the rebuild that is).

 

It could very well be a number of things. Rad cap, or any number of hoses. Just do the test before you order a new engine yet.

 

i will be checking out your advice in the next two hours. but just for something to think about, would you care to mention any of the other things that could make the add coolant light/buzzer go off?

 

You sure its not the add oil light and buzzer? Try flushing the cooling system.

 

ok good to know, guess i should have thought of that. is flushing the system easy to do?messy? i am all for doing what i can myself over taking it to a mechanic (rip-off artist).

 

Yea its pretty easy, unscrew the plastic screw at the bottom of the raditor, flush it, plug it fill it with water.. let your car idle for about 5 min with heater on, unplug and flush again, refill it with 35% antifreeze 65% distilled water and your set.

 

well first off i tried bleeding any air out by running the car at idle with the heater on. i assume it is supposed to spew liquid out for a bit. in less than five minutes whatever air was in there did make it out. after that i heard the buzzer going off again, so i am hoping that was it. shut the car off and refilled the radiator. going for a drive now, and see what happens.

 

that didnt work. checked the water sensor and that looked ok too. guess i will have to try and flush the radiator tomorrow.

 

Well, I'm not sure how flushing it will remove air, but it's probably still a good idea to do -- esp. if you're seeing brownish in your overflow.

But after the flush, keep in mind that you've introduced MORE air to the system than it had before. So 5 minutes of idling probably won't do it. Take scathcart's advice and idle it w/ open cap for 30 minutes. That should do it. Probably wouldn't hurt to go on a drive and 'slosh' everything around good (releasing air pockets wherever they might be) -- come back and maybe even repeat the process if necessary. Top it off and see how it does.

 

i flushed the engine and have replaced the thermostat, the water level sensor, and the radiator cap. the problem still persists. i tried to bleed the air out again, but only did so for less than 10 minutes. tomorrow i will go the full half hour and see if that makes a difference. could anyone tell me if i am supposed to see a lot of fluid coming out while i bleed the air?

 

The sensor for the buzzer is probably bad, mine used to go off every once in a hile, and I had a perfectly fine cooland level..

 

thanks bud, actually i found out the plastic threads were cracked when i was replacing it yesterday before your post and still the buzzer goes off. i am gonna try to bleed the air from the radiator for a full 30 minutes later on today. hope that works.

 

Me and my friend had the same problem your having right now. We flushed his coolant system, replaced all his hoses, plugs and bled the system of air. He has a fairly new motor (under 40k) so we were assuming that it couldnt be the engine. it ended up being his sensor. So we just grounded it. End of story.

 

i just replaced the sensor with a new one, which actually had a different connector. but since its just a ground i used the connector from the old one and just used a crimp. may be i will replace the whole wire straight to the ground. i did look at it yesterday and it looked solid but a little crusty. thanks for the advice.

 

ok ok i think im screwed! i replaced the ground and did the full 30 minute air bleed from the radiator. it stop bubbling after 20-25 minutes. put the cap back on, go down the street and its BUZZING again. i swear im not leaking coolant anywhere. but then again is there some other place i should be looking???? please help.

 

Did you try squeezing the upper radiator hose softly to help the bubbles bleed out? Also try revving the engine to help circulate it as well. I also bled my coolant system by driving aroud for 5-10 minutes and then opening the bleed screw slightly. Alot of bubbles came out. I repeated this several times and it worked for me.

 

hmmm. since i have an S5 your saying i should keep driving around for a 5-10 minutes at a time, stop pop the rad cap and let the air out and then repeat several times?

 

I wouldnt recommend popping the pressure cap since.... well because its pressurized and can pop off and hurt you. I am talking about the bleed screw on the left side of the radiator.

 

i dont think S5 models have those... atleast thats what scathcart said in the first reply to my original question. actually just checked on my car and dont see one. i did notice though when i am done driving after all the hub bub mentioned above that there was quite a few bubbles or air that would rise up as i loosened the cap and it would go through the over flow hose. loosen the cap is what i really meant. i wouldnt literally pop the radiator cap off....hehehe dont need the hot coolant shower. i will try what you suggested for sure. just really want to get my seven back on the road. thanks for your help.

 

Some people may have a small black plastic piece that needs a phillips head to remove.

 

cool man thanks for the pic. i see it on yours but i do not have that same bleed screw. wish i did.