I have been thinking that I have a leak where the headers meet my engine (boooo) and I think it was confirmed today.

I filled up for about $43 for 14.4 gallons of gas. I had driven 377 miles since filling up last time. That averages out to be about 26 mpg. So do you guys think I have a leak?

Since college has started I have been driving 3 times a week ( 6 roundtrip ) each trip is bout 17 miles on the interstate going 70 with the AC on only on the way back. I think I have floored it twice. The rest has been 55 and 45 mph driving.

 

I don'r have aheader so I can't really voie my opinion there due to lack of experience, but that MPG doesn't sound all that good. What MPG were you getting before you started suspecting the leak?

 

well i have got 31mpg going 68ih with the air on, but it was only a few gallons worth

 

No signifigant hills or anything of that nature? Any long periods of idle while you were talking in the parking lot or anything? That does sound a bit low especially if you've pulled 31 in the past, usually you can see, hear and/or feel an exhaust leak at the headers, have you torqued or tightened your exhaust manifold bolts lately?

 

Well I did sit in a parking lot for about 5-7 minutes with the AC on max, so my sister could approve of the flowersand arrange them thatI got my gf. That is the first time ive done that.

My gas has seemed to be going down more laetely, but I thought it was the interstate driving because I havent really ever done much of that so often. I just went out there and let the car idle with some foil over the flange where the headers meet the engine. I didnt rev it (grr i forgot) but I couldnt really feel anything. I felt some air by the alternator but I think its from that, and then I got a sheet of alum. foil and was running it over the gasket to see if it would flutter from a leak but it didnt. Though I did sort of hear a wsshhhh sound, but that was on the right side of the headers (if you are facing the engine) and it might be the alt. or something

Any ideaS?

 

If memory serves they Guestimate that 5 minutes of idling is 1 gallon of fuel (No A/C). So that puts you at 13.4 gallons of used fuel driving over 377 miles or 28.13 MPG.... I'd test a few more tanks, just run 1/4 tank or so and fill it to see what you come up with, you may not have an issue at all. I'd try revving it just to be certain, and be sure that you're testing around the base of the headers and not just on top.

 

Thanks for that info! It makes me feel better, but it seems like the needle moves pretty fast. I guess I will do a trip to my college and back, then fill back up and see the mpg.

 

I really hope that isn't true because i spend around 4mins every morning letting the car warm up b4 I take off. On average I let the car idle 5mins+ a day since I don't drive until the rpm drops below 1k. That means I lose out on 5gals a week from idling. I'm still getting around 350 miles for 12ish gals I also have been using the A/C 100% of the time for the past week because it's been 100+. If the 5mins idling = 1gal of fuel then im losing out on 5 gals of fuel each week. Which means I'm getting 350 miles on only 7 gallons.

 

i highly doubt that cars use more fuel idling then driving at 70mph/2700ishrpms

 

It's a really rough estimate, I was just saying that at idle the car does use enough fuel to throw off your MPG pretty signifigantly..... Here's a mathmatical explination for it (and yes 5 minutes as I used in the example above is low...)


RE: Gas usage: Idling, versus restarting the car[/align]
clip this post email this post what is this?
see most clipped and recent clippings[/align][ul][*]Posted by mxyplx (My Page) on Wed, Sep 28, 05 at 23:20[/align][/ul]I have often wondered about this. Here is hopefully some ROM perspective. If you were driving 60 mph at 20 mpg that would use 3 gal/hr or 3/60 = 0.05 gal/min. So 5 minutes would use 0.25 gal, ie a qt of gas for 5 minutes (at 60mph). Idling 5 minutes would be a lot less than that. How much? Well when I drove big rigs (diesel) they told us to shut down if we had to idle over 5 minutes. Those outfits used about 15 gal/hr at speed (3-4 mpg then). I recall being told they used 1 gal/hr at idle = 0.017 gal/min or 0.083 gal for 5 minutes. Assuming the gas burners were similar, burning about 1/10 at idle as at speed, your car would then burn about 0.1 x 0.25 gallons = 0.025 gal/5 minutes at idle. This says nothing about the possibility of extra gas being consumed by the starting (or shutting down) processes. I don't know if extry gas is consumed during start/shutdown, maybe somebody here does. Certainly extended idling doesn't do the cylinder walls any good and the air polution may be greater. I'm guessing that shutting down makes you feel better more than anything. [/align]
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