Where's It Going (coolant)???

[SnowBuck]

Yea, those tablets were standard operating procedure any time we did coolant work on specific GM engines, especially Cadillacs.

Just what are these "tablets" you speak of and where do you get them??? Though I am very hesitant to insert anything in the engine. For instance: radiator leak stop...which ends up "stopping" up more then you bargained for!
A couple of the garages told me to just keep adding coolant as needed - easier and cheaper then opening it up which they say is a can'o worms you don't want to get in to.

 

[TJ Baker]

This is what I used. I have visually confirmed crack(s) in 706 heads in a 2005 LM7. Been well over 6000 miles since I used these and no loss of coolant since.

Edit: I crushed the tabs, mixed with some distilled water and added during a system flush and refill.

https://www.amazon.com/Genuine-GM-12378255-3634621-Cooling/dp/B000QIH3C4

 

[mattbta]

This is what I used. I have visually confirmed crack(s) in 706 heads in a 2005 LM7. Been well over 6000 miles since I used these and no loss of coolant since.

Edit: I crushed the tabs, mixed with some distilled water and added during a system flush and refill.

https://www.amazon.com/Genuine-GM-12378255-3634621-Cooling/dp/B000QIH3C4

That's what I used as well when the second refurb head I received had a small leak on the freeze plug. I probably shoulda crushed em, but I just dropped em in the upper rad hose and followed the procedure to get it up to temp quickly.


Not going to proclaim victory, but I've got about 500 miles and no coolant loss now. I still watch it like a hawk along with my oil pressure. I've got a few more short OCI's to complete and then will send a sample out to Blackstone.

 

[isp5190]

Just what are these "tablets" you speak of and where do you get them??? Though I am very hesitant to insert anything in the engine. For instance: radiator leak stop...which ends up "stopping" up more then you bargained for!
A couple of the garages told me to just keep adding coolant as needed - easier and cheaper then opening it up which they say is a can'o worms you don't want to get in to.

You can get the tablets @ a GM dealer, I also saw them at Advanced Auto in the GM package. I forgot to mention during our research about this, GM recommends adding the tablets anytime the coolant is changed or replacing the water pump or any major component where you loose the coolant.

 

[OR VietVet]

This is what I used. I have visually confirmed crack(s) in 706 heads in a 2005 LM7. Been well over 6000 miles since I used these and no loss of coolant since.

Edit: I crushed the tabs, mixed with some distilled water and added during a system flush and refill.

https://www.amazon.com/Genuine-GM-12378255-3634621-Cooling/dp/B000QIH3C4

@SnowBuck these are the same tablets. Follow instructions as advised. We were just told that any GM engine with aluminum block or heads requires them with the cooling system. We did not question why, we just did it. It is for sure a form of stop leak though.

 

[SnowBuck]

@SnowBuck these are the same tablets. Follow instructions as advised. We were just told that any GM engine with aluminum block or heads requires them with the cooling system. We did not question why, we just did it. It is for sure a form of stop leak though.

These sound like the answer to me. How did you put them in: drop in the surge (overflow) tank or do you need to take off a radiator hose?

 

[OR VietVet]

When I was running shops and we added these tablets, there was still radiator caps on most radiators and we crushed the tablets up and added there. In your case I would add thru the radiator hose.

 

[TJ Baker]

Here are the ingredients if anyone is interested...

 

[SnowBuck]

OK...sounds like what I need since no test shows any leaks!?!?!? Now...If I were to grind them up (maybe a baggie & a hammer) and take off the top radiator hose, and drop it in - How many???

 

[treehan77]

Yeah I smashed em with a hammer. Make sure you didn’t tear the baggie lol

 

[OR VietVet]

Supposed to use all tablets supplied with the blister pack.

 

[Byoung1330]

2005 XL...adding 1/2" a week. Three garages + the Dealer all say: "I dunno"!
No symptoms like rough idle (could balance a nickel on it), loss of MPG (none - gets 22 on the road), smell outside-or-in (none).

Did the big 4 Tests multiple times at different garages: Visual look, Pressure test (always good), Dye Test (no visible leaks), Head Gasket test (fine).
Then why have I added 1/2" coolant weekly for the past year???

Had the same problem on my 04 Tahoe. I added these ac Delco tablets and haven’t had to add coolant in over 2 months. I was adding every week. I don’t believe in the miracle stuff or additives I’m afraid of heater core getting clogged and all that but these are ac delco an I trust most their stuff.

 

[SnowBuck]

OK... hammered in a baggie, dumped in to the upper radiator hose. Now...how long til I see a result: like how many miles?

 

[OR VietVet]

It has to breakdown in there and circulate and then do what it does. I would guess you should see results within 20 miles.

 

[SnowBuck]

Thanx to all that responded. After 4 garages and the Dealer: pressure test/dye test/head gasket test ... all said "I dunno!"... I put in those tablets (ground up in to the radiator hose):

I haven't added a drop since !!!!!!!!!!!!!!

 

[OR VietVet]

GM's answer to Alka Seltzer strikes again.

 

[George B]

Glad to hear it worked. Funny story: A coworker of mine used to work maintenance in a landfill. They used to temporarily stop coolant leaks with ground black pepper dumped into the radiators of the compactors at the site. He said it worked pretty well for a long time on the machines.

 

[OR VietVet]

I have never seen it but have heard about it several times from way back that you can also crack an egg in there for a quick patch to get you home after refilling. My guess is the boiled egg bits would clog the hole.

 

[Larryjb]

When I had my cracked head, I had pondered using the tablets. But, I didn't know (and I'm still not personally satisfied with) the long term effects of these tablets on the cooling system as a whole. But, obviously, lots of people use them and don't report any ill effects.

My personal worry other than the long term effects of the tablets was that if the head was leaking, would that leak open up on something like the Grapevine while pulling our camping trailer into LA. I decided to not even take that chance. That summer we used the '08 Explorer (WOW, the performance of a smaller engine with VVT AND 6 speed transmission!). I have since replaced the head and am leak free. Tablets may have worked for me, but cracking a head when out of the country is seriously not fun.

 

[FrankU]

We use these tablets on the Corvette LT5 engines as suggested by Chevrolet with no ill effects at all.

Just my 2 cents FWIW