Flushed my coolant - Now have problem

thebean311

New Member
Mar 19, 2001
12
0
0
Chandler, AZ
My car is closing in on 6 years old, and I had never changed the coolant. Last time I went to add some coolant (about a week ago), I saw that it was real dirty looking, so I decided to flush it out and add new stuff.

So, I follow the bullittarchive walk through, and everything goes smoothly. I also bled the coolant system, per the guidelines in svttech's thread. I put in the coolant and distilled water and take the car for a drive. During the drive, the low coolant light comes on. I get the car home and top off the radiator expansion tank. I don't think anything of it until I go to wash the car yesterday.

After washing the car, I'm driving and the low coolant light comes on again. I put a bit more coolant in there. I get pissed, so I pretty much filled the thing all the way to the top. I go to drive to work this morning, and the low coolant light comes on AGAIN (after driving less than a mile). I get it home and remove the radiator cap, and a small amount of coolant bubbles out the top.

My question is what is causing that damn light to keep coming on? Will it come on if there is too much coolant? Will it come on if the mixture of coolant isn't correct? I wasn't having this issue until I flushed the system out. The heater blows nice and hot, and the car doesn't seem to overheat. What gives?
 
Nater said:
Is it leaking from any place? Otherwise the system is burping itself and using up the coolant from the reservoir. Assuming no leak or burn-off, it should be fine very quick.

There are no leaks. The burping thing you are talking about is what I thought, but this morning when the light was on, there was so much coolant that a little actually burped out the top when I took the cap off. There was so much coolant that made me think that possibly the light was on because of too much?

How long does the system take to burp? I had the car idling with the cap off for at least 10-15 minutes, and have driven the car probably 15-20 miles since flushing. Shouldn't that be sufficient to burp the system?
 
jstreet0204 said:
Check to see if the float is stuck to the bottom. It may have some build up keeping it down. Also if you have too much water in your mixture it won't float.

Do you have a picture of what the float looks like and where it's located? I could not see anything that looked like a float anywhere in the expansion tank. I looked before I flushed, during the flush, and after. I never see what people call the float.
 
jstreet0204 said:
Check to see if the float is stuck to the bottom. It may have some build up keeping it down. Also if you have too much water in your mixture it won't float.
Now that I think more about it, I think you are right. I might have too much water and not enough coolant. What would be the best way to increase the mixture? Do I have to open the drain again, siphon liquid out of the expansion tank, do something else?
 
Get one of those testers with the little plastic balls in it. Drain some out, and add some antifreeze. run it for a while to let it mix up then test it. It may take a few times before you get it right. Personally, I run 75/25 water to antifreeze in the warm months, and I just ignore the light.
 
I haven't looked at my 03, but my Moms 94 had the level sensor located on the end of the shaft of the overflow cap.

Clean the two exposed contacts with a wire brush. The contacts allow a small charge to pass from one throught the fluid to the other. If they are corrded, no signal is received and you get a low level light.

rad_overflow_sender_cap.jpg
 
thebean311 said:
It's a 2000 GT.

Jinx, the '99+ stangs don't have a shaft like that. It's just a plastic cap. There is nothing attached to it.

OK. I wasn't sure, but there has to be a sensor somewhere for low level. And it's possible that the contacts have some minor corrosion built-up on them. Keep us posted :nice:
 
Does the light come on and stay on?? When I got my 97GT I didn't have a problem. Once I got the coolant exchanged out it, in the cooler mornings the light will come on for about 1 min then go out the entire day unless it's really cold and it's cooled completely off. I just ignore it caues I figure it's something with the sensor. I've had the coolant tested and it's just fine also.
 
Someone in this thread said that the floatie wouldn't float if the mix had too much water in it. I have one of those testers with the floating balls, and only 1 ball floats. I'm thinking that my mix is probably a little less than 50% antifreeze. Maybe this is why the dealie isn't floating and making the sensor go off. I'm going to keep an eye on it, but next time I change my oil, I think that I will drain a little of the coolant mix I have in there now and replace it with 100% antifreeze to try to bring the mix up.

Does anyone have a picture of where the float sensor is and what it looks like? I just can't see it.
 
I had another question though. Is it possible to put too much fluid in the expansion tank? The last time I added fluid, I filled it up all the way to the top of the neck where the cap screws on. Could this cause damage? Would excess fluid simply spill out of the tank?