Engine Temperature Question >>

[BadGT471]

I have an 02 GAGT with the 3.4 V6. I was just wondering if there was any merit to starting the car and letting the engine get up to normal operating temps before you drive it. I was just curious if it was bad to start it in the morning and immediately put it into drive, or if maybe you could preserve the life of the engine by letting it warm up before you start driving? This maybe a stupid question, but I was just curious.

Thanks,
Jeff

[atc3434]

Not a stupid question. This is one of the things you can do to really help an engine. Espcially the noisey 3.4! When the motor is cold, ie sat for more than 5 hours, its not a bad idea to let things come up to temperature before you put a load on it. Coming up to a full 200 degree's isn't needed, but I usually go for two minutes of idle before I touch the gas. By then the noise in the motor is gone, and she's got a little temp in her. Putting a load on a cold engine isn't good for it, your reducing the life, not a ton, but it definatly is a factor in the long run. When you've got 200k on a car you can appreciate having let it warm up before driving it each time!

To help engine life even more, when you go somewhere don't just shut off the engine as soon as you get there. Let it idle for a minute or two allowing the water pump/coolant to pull some of the heat out of the engine. By shutting the engine off w/o idling first, the engine tends to superheat itself. I've seen this happen with vehicles with temp guages. An engineer found this out while doing specific tests to find out what hurts an engine the most and this was it. Let the engine "adjust" to the idle running temp, then shut her down.

ATC3434

The noise you are refering to is it like a low knocking noise? Almost like the motor neede oil. When I cold start my 99GA I hear a knocking noise which sounds like the engine needs oil. I know the oil level is good but was just curious where the noise originates.

[cavingman]

piston slap, happens on our engines all the time.
something about GM making the pistons smaller than the cylinder, so they expand when they get warm, just enough to fit in the cylinder. something like that

Piston slap = not a good thing.

Have you or anyone else ever had a mechanical failure because of it?

Piston slap = not a good thing.

Have you or anyone else ever had a mechanical failure because of it?

[atc3434]

Its actually not piston slap but wrist pin clearnence... similar noise. Its exactly that motor low on oil sound you refer to. It always disapears when you get warmed up, as it should. I've got a 89 Buick Century with 182k on it thats been to the redline more times that I've started my grand am, and the good old 3.3 has always rattled when cold, and quiets right up after a few minutes. IMO you have nothing to worry about. GM v-6's (Other than the DOHC 3.4) are stone reliable. Very very rare to have one have a mechanical failure of the motor itself!

Swilli... great point about letting the motor idle a minute before shutdown. I've always made it a point. You want your metals to heat and cool evenly!

What kind of mileage can I expect to get out of my GAGT?

[atc3434]

I'm not sure... I've got 49k on mine right now, still runs great. I don't see why 150k plus isn't to be expected. Do your regular maintanence, and it'll run forever!

[Licit]

I was letting the engine warm up off and on but had never thought of allowing idle before shutdown. I've heard a couple people say that letting the engine warm up will kill gas mileage, of course with no explanation. Are they going by the brilliant logic that you would save some gas by not warming the engine up, as in 10 mintues of fuel injection at idle is "eating" gas? Anyone else heard this?

[BadGT471]

I've heard people say that all you're doing is wasting gas mileage b/c the cars these days are designed to drive right away once you start them. You don't have to warm them up. That never sounded right to me. Also, the idle before you shut down the car is also new to me too. I never heard of that. The only time I've ever heard of that is back in the older days when Turbos didn't have intercoolers and you would have to sit there and wait for like 3 minutes to let the Turbo cool down if you were pushin a lot of boost.....

[atc3434]

Idling down a turbo is to let it spin down while your still pumping oil. Otherwise if you shut down and that turbo's still a whipp'n, you can cook the bearings. Cars are not designed to drive the second you start them, fuel injection might make it seem that its ready to go because they are idling smoothly and responding to throttle. But the metals inside the engine are designed to operate at high temperatures, and need to warm up before you place a load on them. Idling down, while not as important, is still probalby a good idea, kinda the same concept. As far as mileage is concerned, you not burning much idling. And you burn lots of gas in open loop, which is what the car is running till it warms up enough. You burn tons of gas running open loop, did it all winter with a stuck termostat on another car. Great power, but NO mileage.

[Hot_Stud18]

Originally posted by Stelios
What kind of mileage can I expect to get out of my GAGT?

I was reading in the "USA Today" a few weeks back that GM said they now design transmissions to last 125k miles but before the late 90's they were only designed to last 75k miles. But I wonder how much abuse they been putting there tranny's through to last 125k?

I thought everytime an autoworker said "I pity the poor b*****D that gets this tranny" automatically put 10K on it. That explains why our tranny was junk before it even got to the dealer. Of course they didn't mention that as we drove off and they locked the gates behind for the weekend.

[Mike Jung]

Here was a post I did on Extra Cold Car Starting & Power Steering Fluid in the winter time.

In the summer:
I let the engine idle until the engine coolant temperature needle starts to move or 1 minute minimum to let the fluids circulate & so I can: roll the windows down, put on seat belt, etc...

[andrewe77]

You don't let your car sit there and warm up. You drive it at moderate speeds until it is warm.

Also, you don't need to let it "adjust" to idle after driving it. That's the biggest load of crap I've ever heard.

[atc3434]

Ok, back it up Seriously, some me some reasons why you don't need to let your car warm up. If your driving a car with a 3.4, I know you have wrist pin noise every single cold start. That is the sound of your wrist pins rattling in the piston. Now, do you really think its a good idea to put any load on those parts before they are seated right, and fit well? Another point, different metals warm up at different speeds. So your aluminum heads warm up faster than your steel engine block. You want them both warm and ready to go, otherwise you can end up with head gasket problems. (Anybody with a early neon or anything quad 4 knows all about this!) So letting your car warm up before you even drive it is a good idea. And idling for maybe 30 seconds before shutdown allows the temperature of the parts inside the engine to stabilize a bit before they start cooling. Lets the internals have a decent coat of oil before shutdown, etc etc... This is definatly less of an issue, but putting a load on a cold motor is about the worst thing you can do! Why do you think every motor oil company is so concerned with the first 30 seconds on startup. Because thats when the most engine damage and wear occurs. You certainly don't need to speed that up any!

[JHawk GT]

Sounds like we need to decide exactly what “warming up” means. It would take a long time to reach operating temps when idling because not that much heat is being generated.

Personally, I would never let a car idle for more than 2-3 minutes. Usually, at most, I drive away after 1-2 minutes—in winter, much less in summer. A motor under load from driving will warm up far quicker than one left to idle. But it’s the kind of driving that seems most important. It makes sense that slow driving the first few miles until things like coolant, oil, tranny, etc., can warm up would be best. Safely warming an engine is going to make it last a lot longer.

Some of the problems I’ve heard that are worsened with prolonged idling are: increased cylinder wash (from fuel) which increases oil breakdown and engine wear especially in the cylinders, increased fuel dilution and condensation in the oil which can’t be burned off due to the oil’s low temp, and increased condensation in the exhaust system which isn’t burned off until operating temp is reached. There are others, but these are the serious ones that contribute to engine wear and corrosion. This stuff is going to happen, so shortening the period that it does, by safely getting to operating temps asap, is what I try to do.

[CDW00GT]

Originally posted by atc3434
Its actually not piston slap but wrist pin clearnence... similar noise. Its exactly that motor low on oil sound you refer to. It always disapears when you get warmed up, as it should.

Ok so since I have this noise on startup, is it covered under warranty? Can I get a new shortblock out of it? Anyone have experience of getting a new engine out of it?