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Letting a diesel engine sit

My husband and I inherited a 2003 Ford F250 XLT (diesel) last Spring that has 17,000 miles on it and is in mint condition (never been driven in the Winter). We drove it only for a few months last summer, mainly on weekends towing our boat and then we took it off the road last Fall. (We have another pickup we use the rest of the year). We have yet to use it this year (with fuel prices, we just continued using our other pickup which is gas powered). My husband thinks it?s bad to have the truck sit for a year, but I can?t justify insurance & registration for a few months so my questions are: A) Is it okay for the truck to sit in the garage for a year (or what will be 2 years if we don?t take out until Summer 2009; B) Is it okay to run the engine-idling (not drive on the road) or does that do more harm?; and C) Should we actually drive it on the road and what is the minimal amount of time (or mileage)?

Diesel has a tendency to gel and/or grow mold/fungi. You’ll want to drive it around on a regular basis.

Most will say it is not good to let any vehicle sit for long periods of time .

Seals dry out, tires can crack, even with Stabil in the fuel tank it won’t be good forever.

I’m having a similar problem with my '02 Tahoe which we only use for towing our travel trailer a couple of times a year. We used to travel with it four times a year but not since the gas price spiked.

I had to change insurance cos because the last one (had them for the last 20 years but no flex) wouldn’t change policies (even with us having NO claims in all that time).

The new one is cheaper with the same benefits and allow me to insure the truck for 45 days at a time with no penalty.

Finally, letting the truck idle without running it on the road for at least half an hour won’t help it.

Well it is not likely that you are going to have any problems with it in storage.

It is not a good idea to start it and just leave the engine idle. It would be better to not start it at all. If you are going to start it, it is a good idea to drive it for some distance to get it up to and keep it at full operating temperature for a while.

The note about fuel and the mold etc is true and fuel stabilizer will only work so long. While it is not likely to cause serious damage, it can block the fuel filter and stop the engine. It usually would not be much of a problem if you keep it to no more than a year and you use at least one tank of fuel a year.

Frankly I can't see why you would want to keep two pickups and only use one on rare occasions. You have an investment that is loosing value, even if you don't drive it, and may be costing you insurance (you should keep comprehensive on it all year).  I would sell one.  If you really do need two on occasion, consider renting or a short term lease once a year.  It certainly would be cheaper.