I am looking at a 1986 6.9L IDI F-250 that isnt currently running due to "fuel supply issues". The price is right, so long as this guy didnt screw anything up by running cooking vegetable oil from a local restaurant in the truck. My question is, how will running cooking oil grease from a restaurant affect the engine in this truck in the long run. I am fairly certain no conversion was used in order to burn this type of "fuel". I know these engines are build to burn oil based fuel, what type of damage could this cause to an engine that doesn't have any type of veggie burning conversions done to it. It hasn't been running for over a year but the body is straight, interior is pristine,. Low mileage on the truck, 100k, second owner, maybe 10,000 miles ran on cooking grease oil. What can I expect to need to replace on this truck if it is even worth it to buy after this "fuel" was used. I am brand new to this, so anything helps.

OD

 

Hi,
I've been running used fryer oil for 13 years in my VW TDI and 7.3L F-250.

Running more than 25% fryer oil in a diesel without a conversion kit may lead to unburned deposits in the engine, and loss of compression. The other parts of the engine probably were unharmed.
Treat it like any engine you suspect of having low compression.
1. Try to measure the compression.
2. See how it starts cold. Faster the better. If several cycles are needed, thats a warning sign.
3. Once its warm, turn off the engine and remove the oil fill cap. Observe how much oil vapor comes out of the fill tube. This is pretty subjective.
4. Blue smoke emitted at idle or when accelerating.
5. Oil analysis

On my F-250 the veggy oil screwed up the fuel tank sender after a year or two.

10K isn't a lot of miles . If the owner ran 50% VO or lower, its probably fine.
They get hard to start , especially in the cold weather, when run with > 50% veggy oil.
Ether may have been required, kind of 'self limiting' the veggy percentage below 50%.
So unless the owner was exceptionally frugal or foolish, .....

 

Unfortunately the truck wont start. It cranks fine but won't fire, which is why I am wondering if it just needs a new lift pump. The current owner has already put new lines and caps in it but it still didnt start. Im wondering if changing the lift pump will solve the problem. I can pick it up for under $600 and it is a clean truck. I just dont want to get in over my head on issues that could have arisen from veggie oil use other than the obvious issues with the fuel system being clogged.

 

The important part here is that the entire fuel system is easy to get to and replace if you end up needing to.

Replace the transfer pump, get the truck, verify you are getting fuel out of the filter head, and then bleed the system as shown here:

Absolute worst case, you might have to pick up an IP($550 rebuilt, $100 junkyard), injectors($350 rebuilt with new parts), and some fuel line.
Note that I'd be less worried about the cooking oil wearing the injectors/IP out, than simply them being at the end of their life anyway. You get somewhere around 120-150K out of them, so if it's a truck you like, investing in a new set will really wake the truck up and make it 'like new'

 

There are a number of ways to screw up the VO gig. The guy I bought my F350 from was running VO; he let the truck sit overnight, get cold, and when he tried to start the truck the cold/thick VO caused "something in the IP to break" [his words]. He needed a rebuilt IP.

For me, the question is how much cheaper is this truck than a similar currently-running truck. A non-running truck (non-running for any reason) is worth a ton less money to me.

Roy

 

Good point. Remember also that when you have a "non-running" truck, the seller may well part with it for less, even if it's a relatively simple fix.

BTW, the price here(two posts up): $600. To me, that's easily in "non-running" category, especially with a good interior.

 

almost certainly the injection pump is dead if he didn't properly dewater the oil ..

the water gets into the steel parts of the ip and rusts them .. even just a week with very wet veggie oil sitting in the ip can lead to castrophic rust ..

then again .. if he set the containers to settle for months and then boiled the water out then it may not be a concern .. just depends on how well he prepared the oil .. my guess is strongly that you'll need a new IP .. and probably the one on there won't be a good core .. so you'll need to find a 'good' junkyard core ..

but i would get it for sure if it was straight and nice and with a nice interior .. plus low milage ..

 

ive read that cooking oil is pretty corrosive, maybe just the water in it. But i would plan on doing the whole fuel system if i picked it up.

 

+1 Especially if the rust is reasonable.




+1 Water: yet another way to screw up burning VO.




IMO, straight, clean, dry VO is not especially harmful. What is harmful is water and any junk in the oil. Also, on a related topic, B100 (which is made from VO) is all kinds of rough on all rubber parts. Fuel line, o-rings, pump diaphragms.



Roy

 

Thanks for the info everyone. The truck is parked up a mountain and he needs it off the property before winter. Deal on the table as it sits is $600 and the body and interior are near perfect, especially the interior. I think it is a good deal considering the interior and the fact that worst case I may need an new IP but more than likely I need new lift pump.

One other thing, he said it doesn't have a heater block, anyone have a suggestion for one? Also how hard are they to install? I live in CO and plan on getting into cold mountain air this winter with the truck and want something reliable.

Also, he replaced the 4 speed with a 5 speed from a 92 f-250. Any cause for concern here with premature wear and tear on the connection housings?

Much thanks.

 

Adding a block heater is no problem. Working glo plugs, might be more of an issue. IMO, these IDI motors tend to have glo plug issues...wiring, burned out replacement plugs, controllers...you name it.

5-speed is nothing but up-side. I assume you have a Diesel pattern ZF5...great transmission.

How high will you drive this truck? Naturally aspirated Diesels HATE altitude. Be prepared to want a turbo.

Nice find.

Roy

 

kat's are pretty good ..

https://www.amazon.com/Kats-24150-Wa.../dp/B000I8TQD6

i wouldn't bother with the stock type heater ..

i would suggest a larger one on the oil pan and a small one on the intake manifold ..

size them based on how long you think it'll be plugged in and how cold of temps you expect to experience ..

 

I had trouble with wvo, I was storing some unfiltered wvo in a tank pumped it out and didn't clean the tank out. I later filled the tank with diesel and used that fuel in all my vehicles. After about a month they all quite. There was slime (probably animal fat) stuck to the bottom of every tank, coating every inch of fuel line, filter heads, even got thru all the filters and coated injector lines and injectors. It was a catastrophic night mare even shut down my crd jeep. I spent tens of hours dropping and scrubbing tanks, pulling rags thru fuel lines, taking aprat injectors and scrubbing each individaul piece. I never found anything that would loosen that slime other than 110 degree diesel fuel and rags and scotch brite

 

Any suggestions or comments on what type of fuel lift to use. Electronic is cheaper and more efficient but I would like to have a mechanical one. They are just very expensive. Any thoughts here? I would like to continue running Biodiesel in the truck wth diesel.

 

Expensive? I see after market lift pumps starting at 23 bucks. I, too, like the OEM-style lift pumps for stock-output motors.

You mean biodiesel or vegetable oil?

Roy