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Old 08-23-2019, 11:21 AM   #174 (permalink)
Master EcoModder
Join Date: Jul 2008
Location: NY state
Posts: 492

XJ Cherokee - '00 Jeep Cherokee Sport
90 day: 12.96 mpg (US)

FoFO - '11 Ford Focus SE
90 day: 36.78 mpg (US)
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I posted this on another forum - but I'll put it here too. And I'll add in some more recently collected data. My truck is a 2001 Ford F-350 with (what I believe to be) a tired old 1997 F150 5.4L engine with 230K on it.

TOWING gas mileage has gone from 8 to 10 up to 10-13
TOWING oil consumption has gone from 1 qt/100 miles to 1 quart / 1500 miles

I just got back towing 500 miles through the hills of PA. This trip I have done a few times with this engine and it always ends up needing 5 quarts of makeup oil. This time I had to add 24oz of oil. There was one hill climb where I was running the engine between 3500 and 4500 for a few minutes. I thought for sure it would have used a ton of oil. I have switched on and off (taking a month to get all of the TCW3 gas out of the gas tank) and 1200 miles ago I towed a vehicle back and it was using 1 quart every 100 miles.

Towing MPG is the only real way I can compare gas mileage in a consistent manner.

In its normal usage, I do dump runs or lowes runs with the occasional highway driving. It varies too much to get any sort of consistent readings.

Oil consumption not towing is always 1 quart / 1500-2000 miles. This hasn't changed much since adding tcw3 at 1oz/5 gallons to the tank.

Since posting that, I've started driving it frequently again. I usually won't drive this in the winter months because it's so rusty and there isn't much left to rust away. However, in the summer, I'll take it on the 140 mile round trip to my parents every few weeks just to keep everything working. If this truck sits, the brake calipers end up seized up.

I was able to get 15.6 / 15.2 MPG on two trips going to my parents and back. Usually it's a solid 13.

I believe the increases I'm seeing in this are more of a restoration effect than a fuel additive helping or doing something magical. The biggest surprise for me is the reduction in oil consumption. I tow with this truck quite frequently. If have repeated it a few times now , getting rid of the oil out of the gas and towing - and the consumption comes right back when towing. Then when I start adding it back in, consumption goes down.

I suspect the rings on this engine are quite warn. Same with the valve seals; these 2v modulars are known for having oil consumption caused by the valve seals wearing out. Since this engine did sit in a junkyard before we threw it in the truck, I have no doubt that there was some degradation caused by it sitting. And we all know that as an engine ages, the valves potentially carbon up, the seats catch crap on them and lower compression and rings wear out also causing a loss in compression.

Using it while not towing in this truck, I'm not sure there's enough of a mileage increase or oil consumption decrease to justify it.

However, it definitely pays for itself with the lowered oil consumption I see while towing with it. And the slight fuel economy increase helps as well.

I've started adding it to my Forester (not enough data yet) as well as my Jeep Cherokee to see if there are any affects on those vehicles.
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