On my 1999 Olds Intrigue with 3.5L engine, I was planning to change the
coolant. When I looked at the draincock, though, instead of having the
familiar "wing" (kind of like a large plastic wingnut) to turn, it was just
a plastic plug that barely protruded from the drain hole with nothing to
grab on to.
Thinking the wings had somehow broken off the plug (maybe during
manufacturing), I went to my Olds dealer. The shop foreman took one look at
the drain plug and said that it wasn't broken, but was just the type of plug
that was put in at the factory. I asked him how to get it out, and he said
"just pop it out with a screwdriver".
(As a side note, I asked how the dealer changed the coolant and whether they
replace the plug with a regular wing type drain cock, and he told me that
they don't even open the drain cock; they just pull the lower radiator hose
off because it takes less time to drain the coolant that way . . . so much
for dealers following the shop manual.)
Anyway, I ordered a new genuine Olds drain cock specifically for my car
(about $3.00) and it is a normal "winged" drain cock.
My question (if you're still awake), is: Could some Olds and other GM car
owners tell me if they've seen a "plug" in the radiator drain cock hole
instead of a normal winged drain cock? Or is my dealer just feeding me some
Okay, here's the right way to change the coolant in an Olds Intrigue with
3.5L engine. This is based on the information in the real Oldsmobile
Intrigue Service Manual (GMP/99-WO-2, volume 2), with corrections based on
personal experience today and consultation with an experienced auto
technician at an independent garage.
1. The engine should be cool or lukewarm; not hot.
2. Open the coolant pressure (filling) cap, which is located on the plastic
tank under the hood near the firewall, on the passenger side. It's very
easy to find.
3. The radiator drain cock is a round white plastic thing about 1/2"
diameter on the back of radiator (facing the engine) on the driver's side of
the radiator, very close to the bottom of the radiator. Open the drain cock
by inserting a 1/4" square driver right in the middle and turn it
counterclockwise until it pops out. It will then pop out about an inch, and
the coolant will start draining out. Do NOT attempt to fully remove the
drain cock from the radiator. (Note: The description and picture in the
Oldsmobile Intrigue service manual is incorrect on this step.)
4. Optional - If you want to do a really through job of draining the
coolant, then jack up the front end and put the car on safety stands.
Remove the right front wheel. Remove the engine block drain plug, which is
located on the passenger side of the engine between the three big pullies.
Allow the coolant to drain. Close the engine drain plug. Reinstall the
right front wheel.
5. Close the radiator drain cock by pushing it in while turning. Tighten
completely, but don't overtighen, as it's just plastic. Finger tight with
the 1/4" driver should be sufficient.
6. VERY IMPORTANT: Open the radiator air bleed valve. The valve is a black
plastic thing, about 1/2" diameter, with a fin to grab on to. It is located
at the back of the radiator (the side that faces the engine), very close to
the top of the radiator, on the passenger side. Since it is black plastic,
it's a bit hard to see against the black color of the radiator, but it is
very obvious after you finally see it. You open it by simply turning it
counter-clockwise until it comes out completely.
7. Add a 50/50 mixture of Dex-Cool and drinkable water to the system
through the filling hole in the plastic tank. VERY IMPORTANT: Keep adding
until the coolant starts pooring out through the radiator air bleed valve.
8. Close the air bleed valve.
8. Keep adding coolant mixture until it reaches the FULL COLD mark in the
9. Run the engine. While running the engine, keep adding coolant mixture, as
needed, to the plastic tank to keep the level up to the FULL COLD MARK.
10. Watch the temperature gauge, and shut the engine off when it reaches
normal operating temperature.
11. Install the tank cap on to the plastic tank.
12. Run the engine through 3 thermal cycles (this could take a few hours or
even a few days, depending on how much you drive, since you need to let the
engine cool down each time), and refill the plastic tank with water to the
FULL COLD MARK each time after the engine cools if the coolant level has
13. Check the coolant with a hydrometer to ensure proper freeze protection.
If you are purist, then you can also flush the system with water around
steps 4 to 6.
One other item: The "drain cock" that the dealer sold me (see below) turned
out to be an air bleed valve. More evidence that some dealers don't know a
thing about servicing cars.
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