This has been going on for 2 weeks now, my mpg went from 5.2 to 4.2, and I keep smelling anti-freeze like it is leaking somewhere, but can find no leaks anywhere, and have not had to add any anti-freeze before, or during this time.

Another thing that is puzzling is when parked overnight now my air pressure will drop down to 30lbs, and if left over the weekend, it goes down to 0. It use to drop to 90 to 100 prior to this.

I did have a problem getting water in the system, but have changed filters 4 times in the last 3 weeks and no show of water now.

 

You could have a head gasket leak that is leaking down the side of your block, but since the block is hot when it is leaking, there are no signs of leaking because it is evaporated already.

 

Your probably like me and notice any little smell or hear any noise even if it's not there. It's been getting cooler and mabye using the heat is making it smell a little more like antifreeze.

That also is why the air is losing pressure. Temp drops will make that happen. Contraction of air hose fittings and the like make small amounts of air leak out. Not a problem in warmer weather, because the fittings are not contracting.

My first inclination anyway.

 

My truck would hold air pressure over a weekend. Now it's at 20lbs overnight.

 

Well since no one can identify the original post problem including me.. I'll just add to the list of problems & say mine leaks down to 20 lbs overnight too & i cannot find the leak. soaped everything with special leak detector that when it bubles the bubbles stay there for 12 hours & still nothing. so i'm lost on that one too.

 

Winter fuel mpg?

Are you smelling a/f inside or out? Is the antifreeze going down at all in the expansion tank? Have you checked the oil for contamination? Look at your hose connections, bottom corners of rad, etc. Try tying a plastic bottle to your radiator cap overflow hose to see if it collects antifreeze. When a/f leaks externally, on hot components it will usually leave a white, chalky residue behind.

If you leave it out overnight, your RES air might be getting cold… ; )

 

Still have not found the reason for the mpg drop, but went to check my Truck out today after it sat for 3 days and when I pulled up I noticed it was leaking AF underneath? That was not a good feeling but opened the hood and found the O rings around my oil cooler were wore out and it was leaking from there.

I guess this is the reason that I could not find the smell of AF as it was such a small leak until it finally gave way. Have to wait until Monday and get the parts for this. I hope this fixes my smell of AF, but still stumped by the drop in mpg, as I have not a clue to what is going on here.


11-30-2008 02:21 PM
bob h


Winter fuel mpg?

Thought this might be the problem to start with, but it did this last year when fuel was switched over to winter blend, but after a couple of weeks it came back up and stayed there until now. Hard to figure on this one!

 

When is the last time you had a overhead done?

 

And the charged-air preassure checked?

 

That "charged air" could be a clue. I was not getting very good fuel economy on the truck I'm driving. Then, about two months ago, it blew the turbo. Since it's been replaced, it's been doing quite well on the economy. More than a mile a gallon more. You might also check that system for leaks.