When driving a manual transmission vehicle, I usually put it into neutral when I'm going to come to a complete stop (ie: stop sign, red traffic light, etc). In automatic cars, people generally just leave it in drive the entire time when braking to a halt. I've recently been throwing it in neutral, same as if I were I were operating a MT... I am curious if this harms the AT in some way.

11/11/2011 9:58:50 AM

It doesn't hurt the transmission. But it's also entirely pointless to do it and possibly could be dangerous (one less way to control the car if something unexpected occurs).

Also, if you're driving a new-ish car (i.e. not your Porsche or Mazda) with a manual transmission you're better off leaving the car in gear until you are close to a complete stop. Coasting in gear usually shuts off the fuel injectors, thus you'll benefit from better gas mileage.

11/11/2011 10:09:40 AM

Quote :

"Coasting in gear usually shuts off the fuel injectors, thus you'll benefit from better gas mileage."

This is the kind of info I want. I'm not sure if the IS250 is setup in this way, but I will assume so. Especially at <10 mph, you can really feel the car "push" while braking... Hence one reason why I started putting it in neutral.

11/11/2011 10:15:47 AM

^my coasting in gear comment only refers to manual transmissions. It does not apply to torque converter equipped automatics.

11/11/2011 10:35:10 AM

Double clutch that shit bro!!

11/11/2011 3:10:17 PM

Quote :

"one less way to control the car if something unexpected occurs"

http://www.youtube.com/watch?v=OK3KYCEuepA

11/11/2011 4:58:42 PM

Quote :

"Also, if you're driving a new-ish car (i.e. not your Porsche or Mazda) with a manual transmission you're better off leaving the car in gear until you are close to a complete stop. Coasting in gear usually shuts off the fuel injectors, thus you'll benefit from better gas mileage."

To clarify, most ECUs cut fuel off completely on overrun (throttle closed, car in gear and clutch pedal out, rpms over a certain threshold like 1200 or so). This is primarily done so that raw fuel is not introduced to the engine when there's insufficient air to burn it and subsequently pumped into the exhaust partially burned, thus increasing exhausted unburned hydrocarbons. The difference in fuel mileage is low...I'd say almost to the point of being negligible. An example of a case where fuel is introduced into the engine on overrun and partially burned fuel is exhausted is commonly seen in older carbureted cars, which pull lots of fuel when the throttle is closed on overrun. The common indication of this is popping through the exhaust and flames shooting out the exhaust on deceleration...and is commonly seen on race cars, where obviously emissions aren't a real concern.

There have been several ways of dealing with this phenomenon ever since the very late '60s and early '70s...most electronic injection systems have fuel cutoff on overrun, even the first Bosch L-Jetronic systems. Other manufacturers have installed dashpots or diaphragm linkages that pull the throttle slightly open to provide air to burn the fuel...this system uses a vacuum threshold, as manifold absolute pressure drops (vacuum increases) a LOT when the throttle is completely closed at speed.

There's no reason really to put the car in neutral. Any energy produced by the crankshaft is absorbed by the torque converter in a stall condition, and the byproduct is heat. At such low speeds, this heat is easily dissipated by the fluid cooler. The internal clutches in the transmission see much lower load than if power is applied during acceleration. You might save a very negligible amount of fuel if you put the transmission in neutral or park. And we can pretty much assume that the extra wear from leaving the car in drive is very negligible...to the point of being a non-issue.

11/11/2011 6:16:33 PM

My 2002 Grand Cherokee has 140k miles on it. I haven't really looked super closely but it appears both valve cover gaskets are leaking oil through them. Also, the past couple of oil changes I'm taking 5 qts out and putting 6 in, changing it every 4500-5000 miles using Mobil 1 Full Syn and their best filter. Is this a bit more than "comfortable" for a WJ with this kind of mileage on it or is it reaching the "to be expected" point?

11/12/2011 11:50:54 AM

don't forget that the oil filter can hold a lot of oil. You may be taking out more than you think in the oil filter, but a new filter is dry and soaks up the oil you put in.

11/12/2011 6:56:52 PM

say about half a quart for the filter, so you're burning about half a quart in 5000 miles. that's not excessive imo.

11/12/2011 8:10:39 PM

oh durr. I forgot about the oil filter.

11/13/2011 8:44:36 AM

Btt

11/25/2012 7:52:06 PM

guessing this was bumped for someone besides me but oh well...when my car (99 Taurus) idles, the heat goes dead; from blowing hot to cold air. As soon as I start moving again its fine. I know nothing specific about automotive heating so besides replacing the thermostat, (which I'm not sure would help since it's not overheating) I don't know what else to check.

11/25/2012 11:31:15 PM

have you checked the coolant level?

[Edited on November 25, 2012 at 11:42 PM. Reason : or it may have air in the cooling system]

11/25/2012 11:40:22 PM

I did just now, and it is not low.

11/25/2012 11:44:35 PM

water pump might be going

[Edited on November 25, 2012 at 11:50 PM. Reason : but make sure there's no air in it first. ]

11/25/2012 11:45:45 PM

Ill check for air tomorrow, and see if anything obvious is off with the pump. It actually looks pretty easy to change (sits high up like a lot of alternators sit on many cars) maybe ill change the coolant and the pump over the break and see if that helps.

11/26/2012 12:09:24 AM

Where I live, we have 95 octane and 91 octane petrol available at every station. 91 octane is 25% cheaper.

I have a 2005 manual RAV-4, and I have been using 95 octane since I have had it (2 years). Am I throwing my money away?

11/26/2012 6:31:48 AM

probably. what does the owner's manual say you should run in it?

[Edited on November 26, 2012 at 9:05 AM. Reason : ^^when was the last time you did a coolant drain and flush?]

11/26/2012 9:03:41 AM

Re: '99 Taurus without heat:

Maybe a vacuum leak or something regarding HVAC actuators? When the air goes from hot to cold, does it do so pretty abruptly?

11/26/2012 10:19:49 AM

cold air at idle and warm air when revved up is a classic symptom of air in the cooling system

11/26/2012 10:27:06 AM

you measure octane different over there don't you??
Straight RON instead of
(r+m/2) (AKI) like we do.

basically your 95 is our 91 and your 91 is somewhere in the mid-low 80s on our scale.

almost any engine without a distributer will retard timing based on knock and you can run damned near anything flammable in them. (not really but you can run regular in a car optimized for premium... you're just leaving a decent chunk of HP on the table)

[Edited on November 26, 2012 at 10:30 AM. Reason : .]

11/26/2012 10:28:57 AM

Quote :

"Where I live, we have 95 octane and 91 octane petrol available at every station. 91 octane is 25% cheaper. I have a 2005 manual RAV-4, and I have been using 95 octane since I have had it (2 years). Am I throwing my money away?"

If you're not in America then your octane rating is calculated another way. 91 octane in Saudi Arabia =/ 91 octane in America. Bottom line though is consult your owners manual and use whatever they say to use. Using a higher octane than specified by the manufacturer is throwing your money away.

11/26/2012 10:31:24 AM

I've owned a car that recommended 87 that ran a *lot* better on 89. But that was a 20+ year old engine with a variety of other issues, so who knows what was responsible for that oddity.

11/26/2012 11:12:15 AM

whomever set the timing.


my jeep liked 89 too... but then that's what i timed it for.

11/26/2012 11:40:09 AM

Coolant was changed about 10k miles ago but its been about 3.5 years (I dont drive very much)
Tried just letting it warm up with the cap off today, no luck but ill borrow a better jack and try again later when I can get the car tilted more.

The jump from hot to cold isnt as sudden as i thought, 10-15 sec. The jump from cold to hot is instant. As soon as I revved it a little the heat came back immediately.

for my two cents on the octane rating, I used to drive an 87 recommended car that got about 7 cents a mile at the time on 89 and 9 cents a mile on 87. Could have just been my driving but I was ok with that if it saved me money. You could try checking that but at a 25% percent price difference, it will be difficult for you to be saving money unless its designed for the higher octane.

11/26/2012 12:22:07 PM

go park it on a hill

can you hear the sound of water trickling in the heater core at idle?

11/26/2012 12:46:12 PM

My corolla had the same heat issue and changing the water pump solved it.

91 RON is 87 usa octane, basically regular gas.

11/26/2012 5:51:37 PM

Wouldn't that solve the air bubble issue too though???

I had a similar issue with my Subaru and had to use the upper radiator hose as a pump.

11/27/2012 7:01:23 AM

Quote :

"Wouldn't that solve the air bubble issue too though???"

if you burp the air out of the system like you should after you replace the water pump, then yes

11/27/2012 8:41:45 AM

Miles on the taurus? Unless I heard the waterfall or gurgling sound from inside the cabin I'd 2nd the water pump; the impeller blades may be almost gone on the inside if its over 150k on a metal impeller. Slow cooling when stopped from hot to cold means your cabin blower is pulling all the heat out of the interior heater core but the coolant isnt flowing enough to provide any more heat. Revving the engine gets a little more push of coolant from whats left of the water pump blades and provides the heated coolant again. An air bubble could do the same thing but I've always heard the water sound whenever it affects the interior heater core. Try the burp method first (best to wait until it reaches operating temp plus revving it a bit helps) and if nothing changes then pull the water pump to inspect and/or replace. Another way to check if its the pump is when this is happening monitor your engine temp gauge and see if it starts to rise when idling and drops back down when you accelerate or rev up.

11/28/2012 11:45:47 PM

Back to the manual thing, bear with me as I'm a noob:
(1) On a flat surface, can I just leave the car in neutral when I park with the e-brake on?
(2) At red lights, do you guys leave it in neutral or leave it in gear?

-Shame

11/29/2012 12:38:58 AM

My isb makes more noise than my throwout bearing so I keep it in gear at stops.

11/29/2012 12:54:19 AM

1) Yes, but I put it in gear out of habit after I found my car had rolled halfway through a slightly inclined Smithfield's parking lot one night even with the e-brake on.
2) Neutral, less wear on the throwout bearing; over time it adds up.

[Edited on November 29, 2012 at 1:04 AM. Reason : .]

11/29/2012 12:55:58 AM

I'll change a tob and you can change an isb. One is literally a wear item. Sadly I need to do an isb on an ancient Crx ( hiro????)

11/29/2012 1:28:04 AM

92,000 miles on the Taurus. Wont really have time to mess with it for a few weeks, I'm not driving it much right now and I have finals coming up. Ill try to burp it more thoroughly this weekend and go ahead and order a pump if that doesn't work. I'm not hearing any gurgling but I'll change the degas cap too when I burp it. I've been monitoring the temperature gauge pretty closely since this all started and I haven't seen the needle rise at all. Even a slight rev brings the heat back though so maybe it's just started going bad?

11/29/2012 8:16:18 AM

^^Thats a little different then, lesser of two evils if your pilot bearing is already loud and on its way out.

^Thats relatively low miles def do the burp tests first.

11/29/2012 8:43:41 AM

Quote :

"Back to the manual thing, bear with me as I'm a noob: (1) On a flat surface, can I just leave the car in neutral when I park with the e-brake on? (2) At red lights, do you guys leave it in neutral or leave it in gear?"

I only park in gear when on a hill. Otherwise the e-brake should suffice, assuming the cable is tightened within spec. And as already mentioned, in neutral at red lights for the stated reason.

11/29/2012 9:22:30 AM

i was taught that (on a drum brake parking brake) that it's best to use the gears to hold the car still. on a disk it doesn't matter so much but drums will warp if held under pressure for a long time.

11/29/2012 10:47:31 AM

I always just park in gear and rarely use the handbrake.

11/29/2012 1:46:15 PM

^^ that's been debunked

11/29/2012 4:44:46 PM

How where ?

It's materials 101.

11/29/2012 6:41:14 PM

youre telling me a brake pad, made of paper and planters pots, will warp cast?

11/29/2012 6:48:14 PM

if it's hot enough

11/29/2012 7:21:23 PM

Integrate the deflection by force over infinity... And yes it will...


I'm not saying parked at the movies it will but left in the driveway for 5 months... Damn straight it will.

11/29/2012 7:30:01 PM

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

The issue is pad material transfer and that's just not an issue for a parking brake

11/29/2012 9:02:24 PM

nothing at that link has anything to do with a drum brake parking brake

11/29/2012 9:07:06 PM

Wait, the post about the force itself actually warping it was serious?

11/29/2012 9:23:38 PM

are you familiar with drum brakes?

11/29/2012 9:32:26 PM

Yes, it's not warping

We are talking nodular cast iron? What is that, ASTM A536?

[Edited on November 29, 2012 at 10:50 PM. Reason : And a force applied with a small stretchy cable? Yeah, they're safe.]

11/29/2012 10:48:58 PM