Car performing better on reserve fuel tank / near empty
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Joined: Nov 2013
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From: New York City
2009 C300 Sport 4Matic
Car performing better on reserve fuel tank / near empty
Hi guys,
Bought a 2009 c300 with 52,000 miles almost 3 months ago. First car, waited 'till I could afford the Merc!
Naturally I've been keeping the tank full, of top tier premium 93 only and even gave it 1 bottle of techron concentrate when I got it in October.
I'm noticing a strange pattern, the car seems to perform better (accelerates faster, less bumpy ride) when low on gas. This effect seems to take place when there are around under 75 miles remaining, and gets better when it reaches the "reserve fuel tank" warning on the dash.
Does not matter if I am in sport, comfort, or selecting gear ranges. Seems to perform consistently better in all modes when low.
Has anyone noticed this before, is it even possible? Is there actually a second "reserve fuel reservoir" that is perhaps performing better than my main tank?
I'm hesitant to give it a second bottle of techron because I read here only to do it twice between oil changes and I am not sure when the last time an oil change was performed, about to go for one. Any advice on this phenomena would be appreciated. I am currently hesitant to fill the tank because the ride seems to get more harsh.
Bought a 2009 c300 with 52,000 miles almost 3 months ago. First car, waited 'till I could afford the Merc!
Naturally I've been keeping the tank full, of top tier premium 93 only and even gave it 1 bottle of techron concentrate when I got it in October.
I'm noticing a strange pattern, the car seems to perform better (accelerates faster, less bumpy ride) when low on gas. This effect seems to take place when there are around under 75 miles remaining, and gets better when it reaches the "reserve fuel tank" warning on the dash.
Does not matter if I am in sport, comfort, or selecting gear ranges. Seems to perform consistently better in all modes when low.
Has anyone noticed this before, is it even possible? Is there actually a second "reserve fuel reservoir" that is perhaps performing better than my main tank?
I'm hesitant to give it a second bottle of techron because I read here only to do it twice between oil changes and I am not sure when the last time an oil change was performed, about to go for one. Any advice on this phenomena would be appreciated. I am currently hesitant to fill the tank because the ride seems to get more harsh.
Last edited by JohnnyC300; Feb 5, 2014 at 01:19 AM.
Thread Starter
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From: New York City
2009 C300 Sport 4Matic
I thought about this, and looked up the weight of a tank of gas and it seems to only be about 100lbs, I don't think this kind of difference could be accounted for by that. Could it be that the techron concentrate (which I had put in when it was near empty as directed) is at the bottom of the tank (even after several refills)? Starting to fear something is broken the car feels like it should near empty.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
This makes no sense other than the weight issue. Fill the tank & check the fuel pressure at the Schrader valve on the front fuel rail that links the injectors. s/b > 3.8 bar or 55 psi.
You could repeat this with the tank close to empty & see if there is a discrepency.
You could repeat this with the tank close to empty & see if there is a discrepency.
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From: New York City
2009 C300 Sport 4Matic
I will, thanks Glyn. Also I've read your posts and you seem knowledgeable on oil and additives, what is your opinion on me adding a second bottle of Chevron Techron Concentrate (12oz) without knowing if the cars previous owner ever used it. I am changing the oil as soon as I can and have read before an oil change is the time to use it but am also weary of using more than two per oil change.
Specifically, I've driven about ~1,000 miles / 1,6000km since last using Techron, and don't know if it has ever been used before in the car.
Specifically, I've driven about ~1,000 miles / 1,6000km since last using Techron, and don't know if it has ever been used before in the car.
Last edited by JohnnyC300; Feb 5, 2014 at 10:24 AM.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
A second dose of Techron will do no harm at all as long as you don't exceed the treat rate specified on the bottle.
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From: New York City
2009 C300 Sport 4Matic
The treat rate is two per oil change and as the car's new owner I'm unsure if it has had more than the one bottle I utilized, so I suppose it best I refrain from a second until post-oil change.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
The treat rate is not two per oil change. That is an old wives tale. What I mean is don't exceed the dose rate on the bottle of concentrate per tankful.
Techron in very high doses can become slightly aggressive to some yellow metals. More is not better. At standard treat it is 100% safe. Techron works quickest in stop start frequent heat soak mileage.
Techron in very high doses can become slightly aggressive to some yellow metals. More is not better. At standard treat it is 100% safe. Techron works quickest in stop start frequent heat soak mileage.
Last edited by Glyn M Ruck; Feb 8, 2014 at 09:50 AM.
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From: Illinois
'08 C300 4Matic Sport, '02 530i
Thank you for the inquiry. There is no need to change your vehicle's oil after using the Techron Concentrate Plus (TCP). However, Chevron does recommend that you use no more than 5 treatments of the TCP per oil change.
With the use of the TCP there is a concentration of the product in your gas tank which is at least 10 times higher than what is in the gasoline itself. This higher dosage might create the chance that some of the product will manage to get into the oil crankcase and react with certain oil additives therein or dilute the oil itself. This is the main reason for the limitation of use - customers would not want to "overdose" and cause an unsatisfactory amount of the product to be diluting the oil. The directions for use are such that any dilution that might occur would not be a problem.
Again, It makes no difference if you add the Techron Concentrate before or after the oil change.
Regards,
Chevron Fuels Technical Services
With the use of the TCP there is a concentration of the product in your gas tank which is at least 10 times higher than what is in the gasoline itself. This higher dosage might create the chance that some of the product will manage to get into the oil crankcase and react with certain oil additives therein or dilute the oil itself. This is the main reason for the limitation of use - customers would not want to "overdose" and cause an unsatisfactory amount of the product to be diluting the oil. The directions for use are such that any dilution that might occur would not be a problem.
Again, It makes no difference if you add the Techron Concentrate before or after the oil change.
Regards,
Chevron Fuels Technical Services
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
There you have it. In all our years of testing Techron I have never seen a case where correctly dosed Techron has shown any reaction with oil additives.
Slight dilution of the crankcase oil is possible but unlikely. Techron is dissolved/dispersed in a light carrier oil.
Techron dosage levels in gasoline are monitored by doing an unwashed gum test. We actually read the level of carrier oil.
My colleagues are just taking a belt & bracers approach.
Slight dilution of the crankcase oil is possible but unlikely. Techron is dissolved/dispersed in a light carrier oil.
Techron dosage levels in gasoline are monitored by doing an unwashed gum test. We actually read the level of carrier oil.
My colleagues are just taking a belt & bracers approach.
Last edited by Glyn M Ruck; Feb 7, 2014 at 06:57 PM.
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From: Illinois
'08 C300 4Matic Sport, '02 530i
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From: Illinois
'08 C300 4Matic Sport, '02 530i
If there is no dipstick, how do you check the oil level? Is there a readout in the instrument cluster that shows you the oil level?
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2012 C300 4Matic
Some model years did not have a dipstick. The tube and a "cap" that looks like a dipstick is still there. In those models, yes it was monitored by the computer and the cluster would tell you how much to add. Mercedes scrapped that stupid idea a while back though.
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2009 C300 Sport 4Matic
So I was incorrect, even though I had read in the manual that there was a dipstick I did not see mine.
The level is dead middle between the min and max, is their anyway to indicate oil integrity via looking at the oil color? Or if in doubt about how long it's been since i've had an oil change, should I just do it? The dash is saying I'm overdo but I'm unsure if it was reset or not last time oil was changed.
The level is dead middle between the min and max, is their anyway to indicate oil integrity via looking at the oil color? Or if in doubt about how long it's been since i've had an oil change, should I just do it? The dash is saying I'm overdo but I'm unsure if it was reset or not last time oil was changed.
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C63 AMG
I thought about this, and looked up the weight of a tank of gas and it seems to only be about 100lbs, I don't think this kind of difference could be accounted for by that. Could it be that the techron concentrate (which I had put in when it was near empty as directed) is at the bottom of the tank (even after several refills)? Starting to fear something is broken the car feels like it should near empty.
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From: New York City
2009 C300 Sport 4Matic
This is why I keep my car as empty as possible. However I've read various things about it better to keep the tank closer to full than empty, so I'm not going to sacrifice this for a performance gain. Can anyone confirm that filling tank occasionally at least is beneficial?
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This is why I keep my car as empty as possible. However I've read various things about it better to keep the tank closer to full than empty, so I'm not going to sacrifice this for a performance gain. Can anyone confirm that filling tank occasionally at least is beneficial?
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From: New York City
2009 C300 Sport 4Matic
I read you should never top up. That when the tank is full it's full for a reason.
edit: When you say top up do you mean fill to the top, or after filling and it clicks adding more? Full service in NYC tend to do that and it annoys me.
edit: When you say top up do you mean fill to the top, or after filling and it clicks adding more? Full service in NYC tend to do that and it annoys me.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Keeping your tank full reduces the chance of moisture condensing out in the tank. Just run the normal cycle from full to close to empty. If you are going to lay the car up for a period then fill the tank.
Topping off the tank when filling is a bad practice. It will usually saturate the carbon canister & the EECS will just dump the excess fuel into the inlet manifold in a controlled fashion via the purge valve.
Topping off the tank when filling is a bad practice. It will usually saturate the carbon canister & the EECS will just dump the excess fuel into the inlet manifold in a controlled fashion via the purge valve.
Last edited by Glyn M Ruck; Feb 13, 2014 at 07:48 AM.
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2013 C300 sport 4matic
Running on near empty is not good as it could overheat your fuel pump and allow dirt or residue from the bottom of your tank into your fuel injection system. In the long run, a clogged up fuel filter will degrade your car performance and you may have to change filter more often. Not worth it.
Last edited by tonyteetime; Feb 12, 2014 at 11:26 AM.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
It will not allow dirt into your fuel injection system. That's why you have a filter. You will only overheat a fuel pump if you run the system dry. Good practice dictates that you refuel when the light comes on. Then all bases are covered without risk. Dirt in fuel will always ultimately get to the fuel filter. Car fuel tanks suffer severe agitation.
