Atok

I've had a few people tell me GM doesn't recommend the use of Coolant Seal Tabs anymore, but I can't find a GM Tech Bulletin saying this. I did find this from March 2004 (read 2/3 way down):

http://www.gmtechlink.com/images/iss.../TLMar04e.html

I'm not sure what to make of this. In one sentence they say:

"GM no longer endorses universal use of seal tabs. Procedures in SI have been specifically written to discourage their use in most cases."

Then they go on to say:

"If seal tabs were installed in a vehicle at the factory, it’s OK that the proper amount of tabs be installed if the coolant must be drained and replaced."

So I just replaced my coolant....do I add the Seal Tabs or not? My Service Manual says add 6 pellets, part #3634621, which is the same # in this GM Tech Link.

So what's the concensus? Anybody replace their coolant and not use the Seal Tabs? Were there any negative effects...like coolant seeping or leaks?

Thanks

c4cruiser

I didn't put the tabs in when I did a coolant flush a couple of years ago based on that Tech Bulletin. I did replace the upper and lower radiator hoses at the time and even reused the original sping clamps. No leaks anywhere so far.

I figured that the tabs that were put in originally helped to seal any leaks especially around gaskets. If this material flows around the gaskets and maiting surfaces and then seals, it should last assuming that you don't use any sort of chemical flush when changing coolant.

skeet

Don't use them.

If I had a problem with porosity in the aluminum heads or a leak I would use what the factory uses - Bars Leak. I had used this product when I first got my 85 and there was an intake coolant leak. After using Bars Leak the leak was sealed for the 12 years I owned the car. I think it is a great product - just shake it well before you use it.

Atok

Thanks for the tip, but according to the service manual the factory uses part GM #3634621 which is in pellet form.

Mr Mojo

Bars Leak is in pellet form as well.

OdinsRage

the best stop-leak are the GM 6 pellets.

This is the SAME as the bars leak pellets, or the tube of ground up pellets. Wont clog heater cores, stops leaks GREAT, non toxic!

I think widespread use was first in the cadillac HT-4100 engines from 82-87. Leaky aluminum/iron setup made it nec.

Some say northstars should have this also...

Never knew they came in the Lt1 from factory... I dont know if I would use them!

onedef92

I've used them twice following radiator flush-n-fill and have never had a problem. I always just crush the pellets first before plopping them into the coolant tank.

MtlSphere

I use Bars Leak in my N* ('98 Eldo).

Though I would recommend that you add the pellets/BarsLeak through the radiator hose and not the surge tank. GM recommends the lower hose but I've had no difficulty adding it through the top hose.

I believe the aim is to have the material in the radiator.

The surge/expansion tank, while part of the pressurized system, is not in the flow. Rather it is located at the highest point in the system, above the engine and plumbed with smaller hoses to allow the escape of air (cavitation) produced by pump activity.

There is a great deal of info about this at Cadillacforums.com. The site is very similar to this one and just as easy to navigate. Do a search and you will find a great deal of info.