Should I shift to D3 to get up a hill that challenges my car?
Posted by A_very_meriman@reddit | askcarguys | View on Reddit | 18 comments
There's a big hill near where I live that I have to pass to get to and from work every day. Getting up it puts a strain on my engine. I'll literally go from 72 to 59 and stay there for a couple of minutes, my engine screaming, as I try to get up this hill. I shifted to D3 twice when going up the hill and it seemed to go better, but it does make the engine pretty loud. I don't know much (anything) about cars and I'm hoping somebody can shed some light on if I should do this and why or why not.
CelestialBeing138@reddit
Take the elephant out of your trunk, and you'll climb that hill much easier.
outline8668@reddit
The computer will shift better than you ever will. Leave it be.
Ok-Anteater-384@reddit
What is your tach reading when this happens ?
A_very_meriman@reddit (OP)
Is this a back to the future joke?
Ok-Anteater-384@reddit
Does your Honda Civic have a tachometer in the dash?
Gunk_Olgidar@reddit
Best possible thing you can do for the health and longevity of a modern engine is drive it up a big long hill every day at highway speed (translation: give it the old Italian Tune Up). Gets the engine hot enough to burn off carbon deposits and evaporate blow-by fuel/condensate in the crank case. All the good things that keep an engine happy.
Whether you manually downshift the PRNDL or put the pedal down and let the car kickdown on its own, doesn't matter.
Just make sure to change your oil on or ahead of schedule (7kmi tops, 5k better) and keep up with the rest of the maintenance. And don't let any check engine lights go unfixed!
A_very_meriman@reddit (OP)
This feels like sarcasm?
Gunk_Olgidar@reddit
Nope. I'm serious.
Modern GDI engines and even moreso hybrids are prone to carbon buildup in the cylinders and on the piston rings because they don't combust completely. Sure GDI engines more fuel efficient than port-fuel-injected engines by a few percent (thanks CAFE regulations!) but they don't burn as clean, resulting in carbon buildup inside the cylinders. You also see this in GDI oil that is jet black at 5k miles, instead of a medium dark brown for PFI engine oil under the same conditions. Been there done that owned both and do my own oil changes w/ lab analysis. (Yes I am that guy.)
When the carbon fouling it gets bad, it clogs up the rings and can make them stick and get stuck to the pistons instead of holding compression against the inside walls of the cylinders. This results in lower compression, rough running (makes carbon worse). When it's REAL bad you get excessive oil burning which makes the problem far worse far faster. Cascade failure ensues. Within a few months of this the engine will burn up all the oil and starve for lubrication, spin a bearing and go BOOM. To add insult to injury this is made worse by scheduled oil changes which are now 10k and more ... because MFRs want to be environment friendly with their ICE cars with less waste oil and fewer/extended oil changes. All of which is bad for you and your car and your wallet.
That Italian Tune Up ... which traditionally was a half hour long run down the Autostrada at over 130kmph with RPMs in the 3-4k range ... or hill climb in your case ... will generate enough heat within the cylinder to a) prevent deposits from forming, and b) burn off existing carbon deposits.
Like I said, it's the best thing you can do for a modern engine. Just don't try it on one with a lit CEL or you might blow it up.
imothers@reddit
It would be very helpful to know what kind of car this is, and if the speeds are km or miles per hour.
If everything is working properly, it should shift to the right gear automatically.
If this is a smaller car (under 1.5 litre) you may have to run the engine at fairly high rpm for maximum power to get up the hill. This will be noisier than normal driving.
A_very_meriman@reddit (OP)
It's a Honda Civic 2007. MPH.
JimiForPresident@reddit
Don’t use D3. It probably won’t hurt that much, but it won’t give you more power either. The car will downshift on its own and use low gears as it deems necessary. D3 just doesn’t allow the transmission to go above 3rd gear, so it stays low gear/high rpm all the time. This is stressful for the engine. The only advantage to D3 is not having to wait a second for the car to downshift when it begins to struggle uphill. You might use D3 going downhill for engine-braking purposes, but that’s a totally different thing, and I normally wouldn’t do it anyway.
HotmailsInYourArea@reddit
Sometimes going uphill it’s best to lock out high gear as well, to prevent gear hunting
nbain66@reddit
The OD off button was always helpful in my Nissan Frontier. It had plenty of power but would always try to lock into overdrive constantly going up hill then downshift.
HotmailsInYourArea@reddit
Yeah some transmissions just arent quite smart enough
nbain66@reddit
They used the same 5 speed slush box in that truck for 15 years. It was probably the worse part of the whole vehicle.
johncuyle@reddit
What gear do you normally climb the hill in, what RPM does it climb the hill in that gear, and what RPM does it climb the hill in third?
littlewhitecatalex@reddit
If it needs to be in D3, it will kick down into D3. Otherwise, just leave it in D4 unless it’s constantly jumping between D3 and D4 and then maybe lock it into D3.
Floppie7th@reddit
Just give it more gas. It'll kick down on its own.