: Invisible leak (coolant)



kjhansen
10-30-07, 09:45 PM
I've crawled around underneath the car with a light, shined the light down around the engine compartment, and I can't see the coolant leak, but I can smell anti-freeze, so I know it's there. It's not losing much, but I know there's a leak! Driving me nuts. I've already drained and re-filled, plus adding the GM coolant treatment tabs. Is there a typical place where these engines leak that isn't readily apparent?
Keith

Ranger
10-30-07, 10:48 PM
Radiator side tanks and water pump cover gasket are common leak points that are hard to detect.

kjhansen
10-31-07, 08:27 AM
Thanks. Since it's a minor leak, is there a radiator additive that will stop it without damaging the radiator or engine? Obviously the GM coolant system treatment pellets won't... Or maybe I just haven't added enough of them.
Keith

misfit6794
10-31-07, 11:36 AM
I wouldn't put any kind of stop leak in the northstars cooling system, chances are you'll just clog something. Look for any white residue around the water pump, or on the rest of the engine, the white residue is dried coolant. Smelling coolant and not seeing a leak was one of the first symptoms when my headgaskets were going bad.

Ranger
10-31-07, 12:23 PM
Don't use anything other than the Bars tabs. Also check the 2 coolant lines that run along the rear head. They are another known leak point. Very hard to get at and replace and almost impossible to see. You may be able to run your fingers along it and see if they come out wet.

kjhansen
11-01-07, 08:12 PM
Smelling coolant and not seeing a leak was one of the first symptoms when my headgaskets were going bad.

BTW, what other symptoms did you have when the headgaskets went bad? I've had it happen twice on other cars. One, a 1970 Buick Riviera, started blowing steam out the exhaust. The other, a 1981 Chevy Citation, started dumping water into the oil. This car isn't doing anything like that. Loses about a half cup of coolant every 600-700 miles or so (estimate). I can just smell the antifreeze when I park it in the garage.
Keith

Ranger
11-01-07, 10:34 PM
Common symptoms on a Northstar are coolant loss, followed by occasional overheating, followed by frequent overheating. They rarely put coolant in the oil. The fact that you can smell coolant is a good thing. That means it is an external leak. I had the same thing on my '97 Deville. Very faint coolant smell when I pulled into the garage. Took me a year to find it. Turned out to be the pump cover. It was so minor that I never got around to fixing it. Still have the gasket 2 years after I sold it. Same thing with my '03. Finally found a leak on the crossover manifold. Had that fixed under warranty.

kjhansen
11-02-07, 08:16 AM
Thanks. That's encouraging. This car was very well maintained by the previous owners, so I'm hoping for many happy miles without major problems. So far so good. All of 3 weeks without trouble! Compared to my Turbo Regal this is great! I was working on it every week.
Keith

lry99eldo
11-02-07, 08:57 PM
Here's one for ya. I had to change my battery about 2 months ago. While I was doing this I couldn't help but to be looking right at the fill tank. I mean it's right there. I noticed that there was some yet where yet shouldn't be. Turns out the return tube fitting that is on the purge/fill tank is broken right at the tank. This is where a peice if 3/8 hi-temp flex hose attaches to the tank on the top front.
It wasn't broken completely through but like sheared half way. I'm thinking well that's probably $300 so I look to figure a way to repair it.
The tank is molded with a rubber kind of something. Not plastic, not rubber. I took the hose off and the first thing I noticed was there was a bit of brass tubing sticking out of the end I just exposed. I wiggled it and the tubing was not far enough into the molded tube to reach the joint at where it meets the tank.
Well, I got a good sharp knife and carefully cut the rest of the way through. After removing it I pulled on the brass tube and it slowly came out. It was long enough to have been in the tank yet wasn't.
After some thought I pushed it back into the tube but past the tank to tube fitting area so that if you put the tube back to the tank the brass tube would go INTO the tank.
So now what? The material isn't going to like epoxy, glue, or anything like that. So, I have a small propane fine tip torch and melted the material at the joint while holding the fitting about 1/2 inch away. Once they both were on fire I jammed the two together, blew the fire out, and went inside to have a drink. Thirty minutes later when I come back the "WELD" seemed pretty good. OK, what to I have to lose. So I hook the 3/8 hose back up, fire up the engine and wait to see if it pressurizes. Yup, and holding fine for 2 months now.
I think the brass tube was part of the design for reinforcement because the engine tourques while the tank is mounted, so movement is to be expected. The brass was never really into the tank or it worked it's way out allowing the joint to fatigue. The leak was minor, but when I had the oil changed a couple of weeks before the tech said it was wet but couldn't determine what or where it was coming from. Guess where?
lry99eldo

kjhansen
11-03-07, 07:44 PM
Very clever fix. I'll have to take a look at mine! I even have a propane torch. I guess the key is to avoid setting the whole car on fire... :histeric:
Keith

misfit6794
11-03-07, 08:05 PM
You could test the coolant for exhaust gases, its quick and cheap, and you can buy the test strips yourself. You definetly want to do that before you drop any money on new parts. Having to add coolant consistently and not being able to find where its going isn't a good thing.

kjhansen
11-07-07, 04:10 PM
You could test the coolant for exhaust gases, its quick and cheap, and you can buy the test strips yourself. You definetly want to do that before you drop any money on new parts. Having to add coolant consistently and not being able to find where its going isn't a good thing.


Who makes test strips that check for exhaust in the coolant? I did a search and only came up with test strips that check the coolant for freeze point, aciditiy levels and pH levels, none of which show exhaust. If I can find these strips I'll buy 'em!
Keith

Ranger
11-07-07, 05:24 PM
Most auto parts stores should have them.

misfit6794
11-07-07, 07:11 PM
Last time I was in napa they had em. Acidity,ph, and freeze points are the least of your worries at this point.

dkorhonen
11-10-07, 01:40 PM
I've crawled around underneath the car with a light, shined the light down around the engine compartment, and I can't see the coolant leak, but I can smell anti-freeze, so I know it's there. It's not losing much, but I know there's a leak! Driving me nuts. I've already drained and re-filled, plus adding the GM coolant treatment tabs. Is there a typical place where these engines leak that isn't readily apparent?
Keith

I have the same problem with my 2004 Deville. With the fact that the engine also appears to be eating a quart of oil every 3000 miles, my wife thinks that this is a warning that we are going to have bigger problems later- she may be right. Please let me know what you have discovered for this problem. My email is dkorh28576@aol.com. Thanks, Dana

Ranger
11-10-07, 05:30 PM
A qt per 3000 miles is just fine. They used to use a qt per 1000. GM now says a qt per 2000 is acceptable. You are doing better than average.