On Sat, 01 Apr 2006 14:36:22 GMT, wrote:

> "Peter Griffin" > wrote in message
> .. .
>> On Sat, 01 Apr 2006 13:26:21 GMT, wrote:
>>
>>> "Peter Griffin" > wrote in message
>>> ...
>>>> Ok...same 99 Gmc Savanna 5.7l as usual...now I just finished changing
> the
>>>> intake manifold gaskets, and I figure I'll scab up enough tonight to
>>>> undertake the coolant flushing tomorrow...Question is a friend
> suggested
>>>> vinegar as a flushing agent...Any pro's or cons will be appreciated...I
>>>> just planned on filling with water getting to temp...draining a few
>>>> times...thanks in advance ...
>>>
>>> I wouldn't waste my time with vinegar. It isn't acidic enough to really
>>> do any good with respect to any iron oxide that may be in the system...
>>> at least over the short term. And if you dont get it completely washed
>>> out, it could offset some of the corrosion protection you might expect
>>> from your coolant corrosion inhibitor package.
>>>
>>> The idea isn't totally off base, just too weak to be effective.
>>
>> not do concerned with the corrosion, more about the dex cool coolant
> mixing
>> with the residule in block
>
> The reason you have products like DexCool and other prepared coolant
> formulations is to offset corrosion in the block and radiator.....ordinary
> ethylene glycol or propylene glycol work perfectly well as antifreezes
> and coolants without any sort of proprietary chemical additives.
>
> I am not sure that that fact has been stated often or is clearly understood.
>
> Yes, you want to get the block and radiator as clean as possible, and a
> thorough water flush is about as good as you can do it. The vinegar is
> not really going to help you.
>
> And if you drop the pH of the OAT DexCool, you will convert the organic
> salts (which are extremely water soluble) into organic acids. These acids
> are not very soluble, and will scum out in the block and radiator.
>
> When I do this job, I normally remove the thermostat, and flush repeatedly
> through the block and through the radiator until everything runs clean.
> (and replace the thermostat with a new one when I am finished.)
>
> Your vehicle is now approaching 6-7 years old. If you have not replaced
> hoses before, this could be a good time to do it. It is hard to predict
> when
> they are likely to fail, but 5 years, 100,000 miles, is certainly getting
> into the
> zone where a replacement wouldnt hurt.

While doing the intake gasket set, I also did the serpentine belt, and
inspected/cleanes everything...The hoses seemed fine, but The thermostat is
a good idea, somehow I overlooked it, probably too concerned with labeling
all plugs/bolts, and cleaning up all the blood from scrapes....should of
just yanked the engine/trans instead of doing the intake in the van
also noticed upper rad hose is seaping now....think it is the disposable
clamps they use now..........