1999 Caddy Northstar V8 Coolant drain advice needed

I am attempting to drain, flush, and refill my '99 Deville. The
factory manual simply says to open the radiator petcock and drain and
then flush if desired before refilling.

As ususal this is a very simplified proceedure.

I have managed to gain access to the petcock, opened it completely,
and the coolant is running very slowly from a cool engine. The
coolant cap is off the surge tank.

What are the tricks to this common proceedure on this engine? The
radiator does not have a coolant cap on it but there is a surge tank
to the side with the fill cap.

I must believe that the shops have a quick way to perform this task,
otherwise this job would cost $400 in labor alone.

Expert help please.

TIA,
Rich

Rich wrote:

> I am attempting to drain, flush, and refill my '99 Deville. The
> factory manual simply says to open the radiator petcock and drain and
> then flush if desired before refilling.

> I have managed to gain access to the petcock, opened it completely,
> and the coolant is running very slowly from a cool engine. The
> coolant cap is off the surge tank.

> I must believe that the shops have a quick way to perform this task,
> otherwise this job would cost $400 in labor alone.

You are doing it right. When you use the radiator drain cock
on the Northstar engine, you will get out all the coolant but
about 2 liters. These engines don't have that much coolant
in them to begin with....only about 10-12 liters which is closer
to what a v-6 engine will have. The Northstar also does not
have block drain plugs....so there is no way of getting out that
last 2 liters. Your best bet is to simply drain out what you can,
and refill with a 50/50 Dexcool mixture. You can also install
the GM sealant tabs into the cooling system before you
refill. This is recommended for the all aluminum engines. Best
place to install it is in the lower rad hose.

We use a flushing machine that simply exchanges the fluid.
Simpler and quicker.

Ian

I found the problem.

In an effort to be 'neat' I had connected a 3 foot tube to the output
of the drain petcock. The fluid just won't drain through it.

I got rid of the tube and it drained just fine. Flushed twice, put
the required sealant tablets in the lower radiator hose and refilled.
Will top off over the next couple of days.

Sorry for the false alarm. I had visions of really having a weird
problem and being hung-up for days trying to figure it out.


Rich > wrote:

>I am attempting to drain, flush, and refill my '99 Deville. The
>factory manual simply says to open the radiator petcock and drain and
>then flush if desired before refilling.
>
>As ususal this is a very simplified proceedure.
>
>I have managed to gain access to the petcock, opened it completely,
>and the coolant is running very slowly from a cool engine. The
>coolant cap is off the surge tank.
>
>What are the tricks to this common proceedure on this engine? The
>radiator does not have a coolant cap on it but there is a surge tank
>to the side with the fill cap.
>
>I must believe that the shops have a quick way to perform this task,
>otherwise this job would cost $400 in labor alone.
>
>Expert help please.
>
>TIA,
>Rich