Hello all,
I am brand new member of this great site. However, I have been to this site many times just reading the forums to answer my question. My most recent problem has left me stumped and I cannot find a thread that describes the same symptoms my car has. I have had my "new" 99 T/A for 10 months and LOVE it! Recently, as the weather turned colder, I have noticed the coolant light coming on). I added coolant the first time not thinking too much about it. A couple weeks later, it came on again. I looked over the system and didn't see any leaks. I also checked the oil and coolant, but i didn't see any cross contamination. I added again and took it to my local garage. They pressure checked my system and found no leaks or loss of pressure. Just a couple days ago, I smelled antifreeze, so I popped the hood and discovered coolant leaking from the cap on the recovery bottle. I haven't modified anything since I have had it, and drive it everyday. I occasionally have a little fun off the line, but most of the time I baby it around. (no sense in jackrabbiting from a red light just to have shift gears in rush hour traffic all the time)
The weird thing is, it may loose enough coolant to set the light off in a couple of days, or it may take 2 weeks, and I am driving it the same way the whole time. The temp gauge never passes 200 degrees. I have noticed the typical valvetrain "tick" all LS1's have. It started about 2 months before the coolant problem. I wouldn't think this would cause anything coolant related, but i'm just at a loss on this. Any ideas?
Thanks a bunch

 

double check for leaks,these ls1s are notorious for water pump gaskets failing check to see if any coolant is dripping onto the bottom of your k-member. i had the samething where i would smell coolant everyonce and awhile and could never find the leak,mine didnt eat coolant like yours is doing though. you can put a piece of cardboard underneath after driving it and let it sit over it for a while and see if and drips,which can help you pin point the leak. mine sits in the garage for 7 months so i think that may have somthing to do with it,cause when i take it out the next spring it tightens back up. i have since replaced the gaskets just so i wouldnt have to worry about it,no problem since.

 

When it was at the garage, i walked under it with the mechanic helping him look for leaks. Nothing was leaking then, however, I now know where it is leaking from (the lid of the coolant recovery bottle) i just can't figure out why. I hope i don't have a cracked head gasket. No oil/coolant mixing is happening, and the temp is staying low. It has to get warmed up aka. driven for a while before it starts. But, sometimes it doesn't leak.

 

is it the overflow cap or the radiator cap?

 

Look real close at the coolant bottle it will crack around the seems and it takes pressure to make it leak. Replace the radiator cap also. If ou have the bypass for the throttle body recheck that.

 

i had a bad radiator cap that was letting air into the system,but was not leaking coolant. i would replace your cap also and check your overflow bottle like outlawz suggested.

 

I looked closer at the cap and it is leaking where th dipstick is attached thru it. I will replace the radiator cap and keep you posted. thanks a lot

 

Here is what may be happening:

The Coolant level sensors often can get gunked up and set a false low coolant light, even though the coolant level is fine. My T/A did it before, and my Grand Prix used to do it all the time.

So you add coolant thinking its low, but its actually not. This causes the coolant level to be too high, overfilling the coolant reservoir when the engine becomes warm. Which would explain why you saw it overflowing out of the reservoir.

Let us know if that sounds like it may be a possibility.

 

When i first added coolant, i couldn't read where it was on GM's dinky plastic dipstick, so i popped the radiator cap and looked into the radiator where it appeared low (it might have actually been fine) i added about a quart total of coolant mix. thats when it all started.

 

Check the pressure on the radiator cap as well. We had a similar problem and couldnt find the leak. we ended up changing the radiator cap and it solved the problem. Just my $.02

 

same here...

I had the same symptoms youre having OP.

 

hey fastvet, how much cubic youre running???

 

[QUOTE=kobraa;12739393]

 

Hi guys, I'm finally back. We had lots of winter precip, so I've been driving my tank alot and kept the T/A out of the mess. I replaced the radiator cap and added about a quart. So far, I have driven bout a week and a half and the idiot light has been happy. Its snowy and slick again, so once I get back behind the wheel of the T/A, I'll do some more driving and keep ya'll updated.
Thanks a WHOLE bunch!