: Coolant System Questions 1996 Cadillac Deville

02-03-11, 03:45 PM
Hello all, new to the forums, been lurking here for a few months... I have a 96 Deville with just over 60,000KM. Been very diligent in ensuring everything is in order as I'm not 100% sure of the service history. After solving a few mysteries I am still having trouble with my coolant system.

Last week I took her in for a flush, making sure that my mechanic is aware that it needs to have GM Coolant supplement tabs added, from the research on this site I made sure to say SIX tabs altogether. Once I got it back from the shop I noticed that he didn't put anything on the bill about the tabs, when I called him he said he put a whole bottle of liquid that did the same thing, which was a bit of a surprise. I'm not sure exactly what he put in there, but I assume it was Bar's C16 or R6. Upon researching this liquid I notice it is NOT recommended due to possibly foaming up in the system.

I've put about 600KM on the car since the flush, have I caused any damage? I am going to talk to him tonight to find out exactly what was done, should I have the system flushed again and the tabs added? Or do I just need him to add the tabs to the system? I'm sure he will work with me whatever the case may be, I just wish he would have listened to my instructions to begin with...

Any and all feedback would be appreciated, I want to keep her as nice as I can for as long as I can!



02-03-11, 05:35 PM
If the system was not leaking coolant before you took the car in for service, there was little or no need to add anything to the system after the coolant change.

The tablets - Bar's leaks #HDC or the equivalent powder G12BP - GM recommended three tablets crushed in the lower hose (the powder equivalent would be about a half tube) - that was to prevent nuisance production line weeps.

Liquid radiator, block, and head sealers were/are not recommended.

My take would be to have the shop perform another coolant exchange. The tablet addition is your call. Go through this forum and up a bit in Technical Tips and get a feel for just how this (very different) cooling system works.

BTW _ Welcome Aboard !!!:welcome:

02-03-11, 07:06 PM
Submariner, thanks a ton for the reply and the welcome. I went to the shop and spoke with my mechanic, he didn't put any Bars products in there, it was a totally different additive designed for rust inhibiting. He provided me with two small bottles of Bars to put in there as well as offering to re-do the flush for me with the Bars powder or tabs. Personally it seems like a good idea to run Bars in the system, he noted that with what he put it there doesn't clog heater cores or cause any issues, he has used it on many vehicles in the past with no issues. I explained that this engine is not like any other and has very specific maintenance requirements.

I will have him flush the system again and add Bars powder or tabs, do you think I've done any damage with the 600KM I have put on it since the flush?

Will review some more technical information in the archives here before I proceed, but as it stands I'll have him flush the system again. Thanks again for your timely response, this place has been a tremendous resource already!


02-03-11, 09:56 PM
I doubt you did any real harm. Be advised that GM no longer uses or recommends the cooling system supplement UNLESS there is a minor seepage problem. As Sub said, using it is your choice. That stuff CAN eventually clog heater cores. Note I said CAN not WILL.

02-07-11, 01:07 PM
I have always used the tablets. When I did my HG job, I noticed that the outsides of the cylinders were all coated with residue/buildup - it was exactly the same as the tan color of the tablets. I used a small wire brush to remove the bulk of the coating - not that I think it really caused any problems, and I did add the tablets when I refilled. I know you're supposed to add them to the radiator hose, but I have actually always crushed the tablets and added them to the surge tank without any problems - they mix right in with the coolant.