1988 7.3L 5spd 2wd how cold will it start?

[GM Guy]

Hey guys,

I have a buddy that has a 99 S10 that is having a security system issue for quite some time, and it has left him stranded ( not fully, but has to unhook battery, or go through a re-learn ,etc. ) and he is getting tired of it and wants to go simple, and so I found on the local classifieds a 1988 RCLB F250 7.3L turbo (either swapped from last year IDI, or a Banks, or ATS kit of course) with a 5spd and 2wd for a grand, and he will only have one rig, and he works at a local feedyard, so he needs it to pop off 24/7, and would like to stray away from plugging it in, but will if necessary.

So the lengthy information is a prerequisite for the single question: In a power outage scenario with no block heater, how cold will a 7.3L 5 speed Dead Cold Start?

I am thinking with good hot batteries and plugs, 10 below is a guaranteed go? usually, it never gets below about 10-20 below, and that is a super cold snap. the usual is sustained is 0 when a front is moving through.

 

[ak diesel driver]

maybe with syn oil

 

[GM Guy]

so with 15w40 dino 0 degrees is probably all?

 

[red]

little bit different since it has a turbo but my experience is the 7.3 doesnt like starting in the cold. i had an 89 f250 7.3L with dual 3" exhaust. once it hit freezing, if the truck wasnt plugged in overnight i had to put a cap on the exhaust pipes to start. doing that though i could start into the teens without much issue, never experienced colder than that.

guess the plugs provided enough backpressure to hold the warmer recently compressed air around in the engine? not sure but wasnt too worried about it because once the truck fired up it spit the caps off the pipes (gently). dont think you would have to do that since the turbo is there providing some back pressure

 

[GM Guy]

how much do you guys think the 5spd does compared to the auto? I think the extra cranking speed of not having to pump oil is worth 5 degrees, isnt it?

 

[THEFERMANATOR]

Also on the 7.3L IDI's make sure and only use MOTORCRAFT/BERU glow plugs in them. I know they can be tempermental to start like the 6.5's can be though. Also you can put in 6.5 glow plugs that are self regulating and use a push button to engage them for extended glow times for cold weather starting. An intake heater would probably help as well for once it lights off.