Wont start unless pluged in below 20

[jpalma]

I just recently bought a 2000 f250 with 340,000 on the clock and not sure what has been replaced lately and what has not. The truck has been starting without being plugged in. But went to fire it up today and wouldn't even start. Its a high of 10F today and sat for about 16 hours. I know if I plug it in it will start but I will be going on a fishing trip soon and I would hate to ruin the trip with my truck not starting after sitting outside all night with no access to being plugged in. Should I start looking into replacing stuff or is this a normal occurance I would think that it would at least start and run like crap for a few minutes. Any Ideas ??

[dieselburner21]

Glow plug relay, glow plugs, what oil do you run in it, things to look at first

[jpalma]

I changed the oil at the end of the summer with some 15-40. Could it be a glow plug or two not getting hot enough ? Or could the relay cause something like this ?

[NoRalPh]

Ten Degrees?? With that kind of mileage (and ya gotta figure the loss of some compression) Plug The Poor thing IN for goodness sake!

The 15W oil isn't helping either, 5W Synthetic would make it start easier.

You can check-out the Glow Plugs & Relay for good measure -> Troubleshooting GPR & GP's

[jpalma]

I do plug it in I just want to make sure on that cold day up north it will not leave me stranded. I will check the relay and give her an earlier oil change and see if that helps.
Thanks for the help.