Coolant leaking: pressure test or dye UV test?

[Tony_1992]

First thank you guys for your answers. I'm really addicted to this forum.
As it is becoming hotter in Florida, I sometimes found the fan in head starts to turn. I thought that's problem of cooling system.
And after checking the antifreeze, the level was fairly low. So I added some antifreeze to it's normal level. But after a day's driving, the level dropped about 2cm in normal speed. And I can see some water(I mean antifreeze) gathering on the cover underneath the car, and the cover was also very dirt. Maybe polluted by leaked antifreeze?

In that case, pressure test and dye UV test, which one should I do?
And by the way, in pressure test, is pump be connected to radiator cap? Where is the radiator?

Thank you guys.

 

[joegr]

Okay, I assume that you will be resistant to this, but I'll post it anyway.
There's really no value to testing to find out where the leak is. (If you know what to look for, you can find it just by looking anyway.) The reason I say this is that all the plastic degrades at close to the same rate. As soon as you replace the part that is leaking, another one will start. You need to replace it all at the same time.
GenII LS8 Cooling System Overhaul

 

[Tony_1992]

Okay, I assume that you will be resistant to this, but I'll post it anyway.
There's really no value to testing to find out where the leak is. (If you know what to look for, you can find it just by looking anyway.) The reason I say this is that all the plastic degrades at close to the same rate. As soon as you replace the part that is leaking, another one will start. You need to replace it all at the same time.
GenII LS8 Cooling System Overhaul

Thank you man. So, what would you suggest me to do with my car now? I just want to find the leak and seal it with welding. Or replace the O-ring if that's the culprit.

 

[joegr]

Replace all the parts as shown in the link I included.
It won't be an o-ring.
Even if you epoxy or thermal weld one of the cracks to seal it, there will be ten more right after that.

If you are going the short-cut route anyway, I wish you luck. You'll need it. If you succeed, let us know. You'll be the first.

 

[Blueberryyum02]

Listen to them they know what they are talking about. I tried the short cut route on the degas bottle its motor craft now after the first dorman died six months after install and the replacement died before I could get the cowl cover on good.

 

[04_Sport_LS]

Where is the radiator?

Behind the grill and in front of the engine. The radiator doesn't have a cap. You would attach the pressure tester to what you would call the overflow bottle... which is located back by the drivers side hood hinge.

 

[Tony_1992]

Behind the grill and in front of the engine. The radiator doesn't have a cap. You would attach the pressure tester to what you would call the overflow bottle... which is located back by the drivers side hood hinge.

Thank you buddy. Is the overflow bottol actually called the degas bottom, or the antifreeze reservoir, or just the coolant tank?

 

[04_Sport_LS]

Official name is degas bottle. You could try renting a pressure tester from one of the parts stores that does that kinda thing. If you still can't determine the exact location of the leak... then the UV dye might help at that point.

Thing is... where a leak drips and where it originated from,,, could be a couple feet apart. If your losing a half inch of coolant from the degas bottle per day... that's a pretty good sized leak.

DON'T try to patch it. Just replace the part. You'll be doing yourself a favor in the long run.

 

[Tony_1992]

Official name is degas bottle. You could try renting a pressure tester from one of the parts stores that does that kinda thing. If you still can't determine the exact location of the leak... then the UV dye might help at that point.

Thing is... where a leak drips and where it originated from,,, could be a couple feet apart. If your losing a half inch of coolant from the degas bottle per day... that's a pretty good sized leak.

DON'T try to patch it. Just replace the part. You'll be doing yourself a favor in the long run.

OK, I'll try to find where the leak is. Maybe loosing an inch per day was a wrong observation, cause I didn't take the compressibility of air into consideration. I'll rent a pressure test tool and see if the pressure can hold for a while. Thanks!

 

[RigsLS]

You're loosing coolant at a significant rate, observed coolant gathering on the cover underneath the car ... why would you think it would hold pressure for a while?

Dye, pressure testing, magical plastic welding, O-rings that aren't there (unless T-stat)
Just give it up my friend, it needs a complete overhaul of the plastic cooling system ... just they way it is. You replace one part, it'll potentially never bleed correctly or properly. It'll simply spring another leak a bit further down the road.

Two things:
1) It has been recently rebuild or only one part changed and it wasn't done correctly.
2) It's the original cooling system and it's rotting from the inside out. The time has come.

Still haven't mentioned the year of your LS (unless I missed it) and this will play an important factor in your parts and rebuilding process.

00-02 is 1st GEN LS
03-06 is 2nd GEN LS

different cooling system parts!

Please do reread post#2 ... it needs to be refreshed as a whole with all new OEM parts
You can try and mickey-mouse it with aftermarket or salvage yard parts but it's not going to work.

Up to you of course.

 

[joegr]

...Still haven't mentioned the year of your LS (unless I missed it) and this will play an important factor in your parts and rebuilding process...

04 V8, according to his other posts.