Pontiac G8 Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
Hey all, as springtime is approaching here in Ontario, Canada. I'm looking at beginning to order all my parts to due a spring tune up on my V6. I'm considering trans fluid change and spark plugs as well. Wonder what everyone's opinion is on doing a trans fluid flush and fill with filter. I bought my car back in October of 2019 at 154,000kms, it's currently at 160,000kms. Any opinions are welcome and if there's anything else I should be looking at for preventative maintenance please let me know, cheers.
 

·
Registered
Joined
·
2,004 Posts
When I got my V6 I changed every fluid in the car for peace of mind.
Trans, coolant, brakes, diff and oil, probably some more I'm missing here.
I didn't do any flushes, not a fan of flushes. With older gaskets and seals in a car sometimes flushes clean to far and cause leaks.
As for plugs stick with AC Delco unless you have a tune. Air filter and cabin filter . Cabin filters can be pretty gross if not changed regularly.
 

·
SUSP3CT
Joined
·
1,000 Posts
Since you just bought the car I would just "reset" everything and change all the fluids, especially engine oil, transmission and filter, differential, and possibly engine coolant. Not sure about the latter though, as some say it's better to keep the system intact from factory. As for the brake fluid, you can switch that when brakes are due. Spark plugs definitely, switch them but keep them stock. Might as well do wires as well. Air filter? Cabin filter?

Best of luck and have fun!
 

·
Premium Member
Joined
·
5,104 Posts
Second draining and refilling the transmission fluid in lieu of flushing. Normally prefer factory AcDelco over aftermarket fluids, however have used numerous Castrol brand products with great results. Replacing the cabin air filter might be a mute point, unless the outside/fresh air mode is frequently used. The re-circulation mode closes the door and recirculates the air in side the cabin and air does not pass through the cabin air filter. Of course, it wouldn't hurt to clean out the compartment to prevent foul smells or odors emitting into the cabin.
 

·
Registered
Joined
·
205 Posts
My suggestions, from about 8 years working on cars professionally:

1. DO replace that cabin filter. They get absolutely disgusting over time. Also, being an owner of a G8 myself, I have noticed that the seals under the cowl are deteriorated and water gets in there more than it used to whenever I wash the car - which means the filter gets wet. Last year I pulled it out and it was moldy. That's not some **** you want in your lungs. I've pulled some filters out that started their life as white or slightly gray, and were black when I got to them. Also, leaves and other **** pile up.

2. If the transmission fluid has never been replaced, DON'T DO IT NOW or at the VERY MOST just drop the pan, replace the filter, and the 3-4 litres fluid that goes with it. If that's the original fluid at 160k it might be fatal to the trans to do a 100% fluid replacement now. Filter & a few litres is your best friend if that's the case.

2. If it HAS been replaced before, you could consider doing a 100% replacement of the fluid, but if you DO, don't do it if it's a "flush" type service. Some shops use machines that actually flush with chemicals and whatnot, others use machines that just "exchange" - the exchange is pretty safe. That's what we used to use - basically disconnect the cooler line, attach two hoses, plug into machine pre-filled with new fluid, then run the engine - trans pumps its old fluid out and fills up the lower half of the machine (basically a big cylinder with a piston in it) which pushes the new fluid back out of the top of the machine and into the car. No high pressure, no chemicals, all dictated by the car's own transmission fluid pressure & flow. You can do just a pan drop with a fluid & filter job, but very often that gets less than half of the fluid out. That's what happened with me on the 5-speed auto - only took about 3-4 litres to refill it after the service, and it's about 10L total capacity if I recall. But again...if it is still the original transmission fluid, the pan & filter service might be your safest option.

3. As for the coolant - flushing is a nice idea but there's a couple things I worry about on the V6 and the big one is the thermostat. I've seen the occasional thermostat be damaged during coolant flushing and on the V6, replacing the thermostat is not a simple job (it's on the back side of the engine between the block and the firewall). Around 160,000km I had the car in for some other work and I just had them do a typical drain & replace on the coolant - that should be more than enough. Unless you're having a problem getting heat from the heater core, or the engine is running too hot and you want to make sure there isn't any clogging anywhere, flushing isn't all that necessary. Dexcool now is not like Dexcool from 1996 - it doesn't build up brown snot in the system like it used to. Dump the coolant and replace it the old fashioned way.

If you REALLY want to flush, you could always drain the coolant, fill with water and a chemical flush, run the engine for a day or two or a good drive at least, and then re-drain it and refill it. But I wouldn't machine flush, at least not at the age your car is at now. I'm not saying it's a guarantee that things will go wrong, but the car's age and the age of the hoses, radiator, etc are more prone to failure at this age than they were when the car was younger. I've seen coolant machine flushing, and even just chemical flushing without a machine, create leaks that weren't there before because it flushed out built-up snot in the system that was actually serving to plug small holes & leaks that would probably have been fine for a while had we not flushed out the booger chunks.

Just my two cents. Do with it as you will.

Source: about 8 years as a tech in Mr. Lube performing hundreds/thousands of these services and seeing the pros/cons of doing them.
 

·
Registered
Joined
·
44 Posts
The transmission cooler went bad in my radiator about four years ago. I ended up replacing the radiator and having the transmission filter and fluid changed. The radiator is an OSC unit from RockAuto. I used waterless coolant from Evans. The transmission shop claimed to use an AC Delco filter and "approved" fluid. The cooling system has given me no problems at all, even in hot summer city traffic. The transmission lasted about 38,000 miles. It was replaced with a Street Smart unit and their own fluid. I'll be replacing the plugs, wires, and coils this year, but at 108,000 miles, it still runs pretty strong for a six cylinder.
 

·
Registered
Joined
·
205 Posts
Yeah, what he said ^^^ ...no wires. Also, I wouldn't rush to replace ignition coils unless you are having misfire issues...I still have all-original coils at 266,000km and no issues. New plugs would be a good plan though.
 
1 - 9 of 9 Posts
Top