DefinitelyDressage.com

To anyone with a diesel truck, how long can/do you let your truck sit without driving it?

I have a 2005 Ford Excursion which is my tow vehicle. I also have a commuter car so I only use the truck for towing, or for other truck-ish things (like getting feed, hauling stuff in the back, and that sort of thing). This saves on the truck's warranty and also on gas.

The problem? If I don't drive it for two weeks, the batteries go deader than a doornail. I had it in for the same problem last spring and they changed the alternator and put in two new batteries. It's still doing it. They checked the whole thing to look for extra drains on the batteries, and said all was well. They also told me that a diesel truck has a lot of background stuff going on so it needs to be driven regularly to keep things charged (they basically blamed me for not driving it enough).

I don't buy it. I last drove my truck two weeks ago and I drove it a lot, and also trickle charged the batteries because it was sluggish to start. I then parked it and locked it and now, 12 days later, I tried to start it and it's COMPLETELY dead. Nothing left in the batteries at all.

Is this normal behavior for a diesel truck? Do any of you park your trucks for two weeks or more and then drive again without issues?

No it is not normal for a diesel. Our dodge diesel has had periods in its life where it wasn't driven except for towing, and we've never had the batteries die for lack of use. I'd get a second opinion from a mechanic you trust.
P.s. We aren't in the cold climate that you are, so you may have more limited battery life due to cold, but what you're describing isn't normal. Do you plug in the block heater when it's cold?

Yes, it's plugged in when the temps dip below zero. It's very frustrating to be told I'm not driving it enough when the darn thing dies within 2 wks (sometimes sooner). There MUST be something drawing more charge than it should when the truck is off.

Here's some good info to read...
http://www.thedieselstop.com/forums/f23 ... or-225726/

Another vote for not normal. Our Ford diesel F350 sits for weeks on end and starts right up.

Not normal. My older dodge diesel sits for long periods of time. Never had a dead battery and it's 17 years old. The truck, not the battery.

FWIW, I had a trickle charger connected to my F250 so when it would sit I would plug in the trickle charger and the batteries would still stay charged.

I don't know much about Diesels but I will tell you this. I use my truck only for hauling but I make sure to drive it at least once a week. If I don't, things start to rust and otherwise break down like brake lines etc. Also, field mice tend to move into the engine and eat wires.

No, not normal. Mine (2000 Dodge 250 diesel) sits for weeks outside covered in snow and not plugged in, and the batteries last as long as I would expect them to. It has many faults, but draining the batteries is not one of them!

DJR wrote:To anyone with a diesel truck, how long can/do you let your truck sit without driving it?

All winter, apparently, as our 2002 sits all winter because it's 2 wheel drive and has no traction. And we're in western MA so it sometimes sits for 6 months or more. The dh may charge the battery (it may actually have 2 batteries?) in the spring, but I'm not sure about that. Probably depends on how cold it is when he tries to start it after it's been sitting.

It does have a problem with the fluids draining out of the torque converter when it sits, and then it'll start but shut itself off. But once he figured out what to do about that he hasn't had any problems with it.

Usually diesels do have 2 batteries.

It really isn't good for anything to sit for a long time. Hard on the various seals in the drive train as they can dry out and start leaking. Overall best to start and drive at least once/month (or so I was told).

My truck doesn't sit longer then 2 weeks normally, occasionally 3-4 weeks. It gets used regularly during show season. In the off season I truck out at least once a month for dressage lessons with my coach (who lives a distance away), and usually drive it at least one other time each month.

It has dual batteries and one alternator, all of which are new within the last 12 months.

I have it scheduled for diagnostics on the electrical system on Monday to see if they can find out if something is draining the batteries prematurely.

DJR wrote:It has dual batteries and one alternator, all of which are new within the last 12 months.

I checked with the dh and our 2002 still has the original batteries and alternator, and still starts after sitting all winter, so it does sound like you have an electrical problem.

We do have one of those battery packs though, because we have a lot of diesel engines that don't get started often enough, and the extra boost will often make the difference between starting right up and maybe not starting.

Deanna, we had the same problem with our MGB (1980 vintage). After 2 weeks of sitting in the garage, a boost was necessary. Frustrating. Bear with me! I think the clock was draining the battery. Anyway, the fix was simple. The mechanic installed a battery cut off switch. Now, you flip the switch to off when you are not going to be driving. You flip the switch on, and the car starts, even after sitting for weeks. Or months in the case of winter. It is a cheap and effective solution.

we had similar problems and replacing the starter curried ours ... really never noticed that the starter wasn't spinning the engine as it once was

I had that problem with my 1993 gas truck. The mechanic traced the drain to the alarm system. Once that was cut, the battery has held charge.

Mine doesn't sit that long often but it occasionally does. Never had a problem with it starting.

How old are your batteries and what brand? If you have cheap batteries in the vehicle that could be your issue. Battery brand really does matter when a vehicle is sitting that long. Someone else mentioned the radio clock; for most batteries this isn't an issue. But cheap batteries (think Auto Zone specials) will go dead quickly when the vehicle is sitting. Also, are you checking to see that there is enough water in the batteries?

Oh..and make certain your connections to the battery are good and kept clean.

The batteries are around 8 months old, good quality truck batteries. It's going in tomorrow for diagnostics.

As an update, the mechanic tells me that the alternator is not working properly. It's very intermittent. When he ran the diagnostics, it was not charging adequately, and when he tapped it with his wrench it suddenly started working better although still not adequately. They tell me that this by itself is enough to explain the problem. The alternator was just replaced earlier this year so I'm getting another new one under warranty (no charge to me). We'll see if that actually fixes the issue ... fingers crossed that it does!

Another update. The repair above was made but I was still skeptical about whether the actual problem was solved.

I just started the truck in -5C (23F) temperatures, and she ROARED to life. Yay! For the past 18 months, that wasn't the case. What a nice change! It seems that the faulty alternator was the problem all along.

Good news, especially since it was covered under warranty!

Good news, especially since it was covered under warranty!