# AC not working on my CTD when diesel level is low



## MP81 (Jul 20, 2015)

Doesn't surprise me - in an effort to keep you from running out of fuel, the car is going to shut down major fuel-economy detractors in order to allow you to make it that last bit of range.


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## obermd (Mar 3, 2012)

I don't know about the A/C but a low fuel warning disabling remote start makes a lot of sense. Don't want to start the car just to have it run out of gas before you get in.


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## smkn600ctd (Dec 16, 2013)

A low fuel message has nothing to do with the ac. I've been fighting the ac shutting down for no reason then working again after restart it or it will work again a few min later randomly for a long while. Each time they thought I was full of crap until I started taking it right in the moment it would stop working. 

They think they figured it out as being the fuse block having an intermittent open. 

As for the remote start, yes...they don't want the car idling and running out of fuel.


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## diesel (Jun 8, 2013)

I always push the limit for low fuel and often drive over 100 miles with the low fuel light on. Never any AC issues during this time.


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## MP81 (Jul 20, 2015)

diesel said:


> I always push the limit for low fuel and often drive over 100 miles with the low fuel light on. Never any AC issues during this time.


Slightly off topic - so I'm guessing the estimated range on the DIC says something around 100 miles, even if the low fuel light is on? Our DIC said something like 80-90 miles when the light came on.


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## MP81 (Jul 20, 2015)

smkn600ctd said:


> A low fuel message has nothing to do with the ac.


It doesn't, but it most certainly could. AC provides extra drag on the belt, which takes extra power to turn. It doesn't deactivate it, it was just a theory.


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## MOTO13 (Mar 26, 2014)

diesel said:


> I always push the limit for low fuel and often drive over 100 miles with the low fuel light on. Never any AC issues during this time.


I never push the limits of fuel like that. Isn't this bad for the fuel pump? If it's like a gas car, it can overheat the pump and shorten its life.


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## MP81 (Jul 20, 2015)

MOTO13 said:


> I never push the limits of fuel like that. Isn't this bad for the fuel pump? If it's like a gas car, it can overheat the pump and shorten its life.


Regularly, yes it is.


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## diesel (Jun 8, 2013)

MOTO13 said:


> I never push the limits of fuel like that. Isn't this bad for the fuel pump? If it's like a gas car, it can overheat the pump and shorten its life.


I am at 162K miles now and never had a fuel pump issue, and I do this with almost every tank. I will have to say "no" based on my experience. I suppose we can revisit this again when I hit 500K 



MP81 said:


> Slightly off topic - so I'm guessing the estimated range on the DIC says something around 100 miles, even if the low fuel light is on? Our DIC said something like 80-90 miles when the light came on.


It varies on what I've been averaging for the past several miles. It goes to LOW based on how much fuel is in the tank, not the actual range estimation. I have seen it trigger to LOW with like 40 mile range, and also with over 100.


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## obermd (Mar 3, 2012)

90% of a fuel pump's cooling comes from the fuel pumped through the pump. Only about 10% comes from the fuel sitting in the tank.


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## MOTO13 (Mar 26, 2014)

I'm not sure what the point is driving to basically fumes. Just to see how many miles you can get out of a tank? I pushed a car once for about 22 feet when I ran out of gas. I was 16. They don't push very easily. You know what? I didn't like it. I especially didn't like the 9 mile walk in the middle of nowhere back home to get gas.


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## jblackburn (Apr 14, 2012)

Could be the AC clutch be disengaging when heated up?

Had the problem with older cars, but never my Cruze (1.4T here though). I'd imagine they use the same compressor between models, though.


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## TheDog (Mar 27, 2014)

There must have been some car, somewhere, at some point in time that had a fuel pump that was likely to melt down if there weren't 4 or 5 gallons of fuel sloshing around in the tank but I've had a Nissan Pickup, Nissan Sentra, Volkswagen TDI, Saturn Astra, a Chevrolet Malibu and now the diesel Cruze and I routinely drive or drove all of them until fuel was very low and have never had a fuel system issue ) with (or had to push) any of them though in my youth I did literally sputter into a station one time in my old Sentra.

Why run them so low? I can think of a few reasons beyond that stopping to buy fuel is an interruption and in the case of the diesels, messy.... If you use discount points (grocery store, Fuel Rewards etc) you get xx cents off the first 20 gallons or whatever. I often have 40 to 80 cents of discount available. If I use those points to buy 9 gallons of fuel instead of 14, that's a few bucks wasted and those points don't refresh for free. Also, in the case of the Chevrolet's in particular, the fuel light comes on VERY early. In the Malibu I would literally have 5 gallons in the tank if I buy fuel the moment the low fuel alert comes on. That's a big bucket of fuel, way more than I need to feel cautious. I often drive as much as 40 miles after the low fuel light comes on and in 110K miles it has rarely accepted a full 14 gallons which means I STILL have over 2 gallons of fuel plus whatever is in the lines etc. Lastly, I often have Shell gift cards I want to use (another way to earn points at grocery store and some stations give you 5c off and all of them at least give you the cash price instead of credit...) and Shell stations aren't always right next to where I am but are on the way someplace.

I sometimes buy fuel at the edge of PA if it allows me to get where I'm going and back into PA regardless of how much gas I have in the tank. This is about the only time I fuel up with more than 1/8 of tank left unless I'm in Nevada or Alaska where there are some truly remote areas.

I don't expect my eccentric reasoning will appeal to most people. I would say that if you have a 15.6 gallon tank (Cruze Diesel) and you are usually pumping 12 or fewer gallons (assuming you don't overfill which with patience you can easily and safely do with Diesel), that's a lot of useful range you could stretch a tiny bit just to buy at the same station each time or wherever you get a little better deal, etc and still not be running on fumes at all.


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## MP81 (Jul 20, 2015)

TheDog said:


> There must have been some car, somewhere, at some point in time that had a fuel pump that was likely to melt down if there weren't 4 or 5 gallons of fuel sloshing around in the tank


Third and Fourth gen Fbodies, haha. Those pumps, due to tank design, were well-known to lose life quicker if you ran below a 1/4 of a tank regularly. Bitch and a half to change the pump too.


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## diesel (Jun 8, 2013)

MOTO13 said:


> I'm not sure what the point is driving to basically fumes. Just to see how many miles you can get out of a tank? I pushed a car once for about 22 feet when I ran out of gas. I was 16. They don't push very easily. You know what? I didn't like it. I especially didn't like the 9 mile walk in the middle of nowhere back home to get gas.


@TheDog said a lot of the same reasons that I follow, but mainly I don't like pumping fuel and by running as far as possible and filling as full as possible, I eliminate quite a few fill-up stops. When you drive as much as I do, that could mean one fewer fill-up per week for me. not to mention the time saved.


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