Coolant leak, confused.

[ms255]

I own a 2005 CTS 3.6L with about 61K miles. I'm still covered under the extended warranty and I plan on getting to the dealer ASAP but I wanted other opinions on this issue.

Back in March of this year, I was driving home and stopped at a store, maybe a 20 mile drive, and there was a very large puddle of coolant under the front of the car. Couldn't see exactly where it was coming from. The low coolant light came on and I put about a gallon of coolant in. The next day I took it to the dealer. They kept it 2 days and told me they pressure tested it twice and drove about 10 miles on it. Couldn't find any leaks.

For the next couple of months I kept an eye on the coolant level and had no problems. Then within the last month I've been seeing small spots of coolant and on my way to the vet, I started to smell some coolant and the low coolant warning came on again. When I got home I added maybe a quarter gallon of coolant and the light was off.

This morning on my way to work, in heavy stop and go traffic, I started to smell it again and actually saw what I assume was some steam coming from under the hood. Once I got out of the traffic I couldn't smell anything and opened the hood at work but couldn't see anything. The reservoir was all the way to the fill line, and the low coolant light never came on.

During this entire time the temperature gauge never came above halfway, which is what is runs at ever since I bought the car.

What I have taken from this is that it seems to happen when I'm in stop and go traffic, both the vet and work drive were such. Other than that I am very confused. Any opinions I would appreciate. Thanks

[txbest1980]

maybe your t-stat is getting stuck open every now and then...just a guess, but maybe something to look at

[josney]

I am going through the same scenario. I can smell the coolant and i can occasionally see the steam from under the passenger side of the hood, between the hood and the windshield. Haven't figured out where mine is coming from yet.

[BlakGost]

Mine was doing the same exact thing for the last 6 months. 48k on the whip. Really had me twisted for a second. Always smelling coolant while driving and then parking to find a puddle of coolant under the car later. Never overheated and gauge never went past halfway. Took it to a Caddy dealer in San Antonio - couldn't find anything. Finally had a chance to take it in here in Tucson - pressure test showed a crack in the waterpump. Also, the thermostat was on it's way out. Warranty covered both. Good timing I guess you can say because it was time to change belts anyway.

[bburt]

When I bought mine a couple of years ago with 41,000 on it, I continually lost coolant. In checking around, it came through that the heads, head gaskets, and block are a minor issue. I went through what was thought to be heater system leaks, cracked head, etc. Finally, a very good mechanic spotted weeping, not leaking around the rear of the heads back by the firewall. He checked his network and found that it itsn't uncommon. He gave the the choice of pulling the heads, milling the head, new head gasket and putting it all back to gether, for about $500.00. He then suggested that I try Alumaseal at $1.95 a tube. I put in the alumaseal, drove it for fifty miles immediately afterward. I haven't had a problem since. Try it. You won't do any damage, and it might work. The leaks are very small and happen under higher pressure and stress on the engine, apparently. At some point, someday, I'll have a shop work over the engine, but until then, it works. By the way, I live in the desert, so the whole sytem is under extreme pressure use all the time, with a/c and external heat requiring higher heat dispersal than might be in other locations. Not an exotic fix, but it just might get the job done.

[josney]

Thanks for the suggestion. I will give it a shot.

[ewill3rd]

There is a water control valve (if I remember right) at the right rear cylinder head area, it is prone to leakage.
Also the Oil Cooler cover plate is in coolant and they are prone to leakage.
Both jobs kind of suck.