Put 1 gallon of Rotella 10w40 and seems like it cranks too long...

[Spinal Tap]

Well the truck runs and drives fine, this past oil change and fuel filter change i went with 1 gallon of 10w40 and the rest 15w40 rotella because its supposed to be real cold this winter... first time ive done this, i had 3 gallons of this stuff and now only one truck.

So, the truck has brand new batteries and when i first fire the truck up it seems to crank longer than normal before it actually starts.
Say its like 20° outside and the truck isnt plugged in, it cranks for 5 seconds or more, the glow plugs work fine.

I was wondering if it had anything to do with the thinner oil i put into the truck?
Anyone else use 10w40 on their 7.3? Well, i had bought a 6.0 and the oil came with that truck, now the trucks gone i have 3 gallons sitting on the shelf for over a year...

Just wondering if the oil was keeping the injectors from firing off sooner.

Thanks

[Zaairman]

I've never heard of 10w40 Rotella? I've only seen the 5w40,10w30, and 15w40? Anyways, have you checked to see if your glow plug relay is still putting out a good voltage?

[pete37922]

never heard of any1 using 10w-40...i use Amsoil 5w-40 all year long in my 6.0L !!!

[Spinal Tap]

Hey thanks for the replys guys.... I screwed the pooch on that one, you guys were right. 10w30

I just went to check the relay. Battery voltage key off. 12.4
Relay output 10.60 volts when its firing up the glow plugs.
Truck fired up right away, its 40° outside.
Battery voltage when alternator is kicked on, 13.1 and slightly raising but i shut the truck off asap.

Maybe im just thinking its cranking longer with the lower viscosity oil.

If it had a few bad glow plugs, is the only way to check them to take them out?
I know its had all 8 put in about 6 years ago. Whats the life expectancy of these ford glow plugs?

[chris'2000psd]

you want to use a 5w40 oil in the winter its thinner

[Zaairman]

You can ohm the glowplugs with a multi meter without removing them. Search for it on here.

[shiz big red]

Is your relay stock? I use rotella 5w40 year round. I'm in Utah been low 20s high teens not too cold but that oil makes a huge difference in starting for sure. If you have the stock relay go take that out and toss it they are ****. Stancor relay is the way to go for sure.

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[rufushusky]

Originally Posted by pete37922

never heard of any1 using 10w-40...i use Amsoil 5w-40 all year long in my 6.0L !!!

Rotella actually has a T5 syn blend...

Shell Rotella T5 10W40 Synthetic Oil, 1 gal. - 8030156 | Tractor Supply Company

like others have said I would check your GPs and GPR...mine was putting out 3 volts. I got a stancor on the way.

[Spinal Tap]

Originally Posted by shiz big red

Is your relay stock? I use rotella 5w40 year round. I'm in Utah been low 20s high teens not too cold but that oil makes a huge difference in starting for sure. If you have the stock relay go take that out and toss it they are ****. Stancor relay is the way to go for sure.

Sent from my ADR6350 using AutoGuide.Com Free

Yes, the truck is 100% stock except for the added hp box. Do you have a part number for the relay, something i can get at NAPA like a ST-85... the relay works, but the voltage was low, HUGE drain from the glow plugs.
But the batteries are 1 month old interstates with like 800 cca each.

The batteries were 3 plus years old and went south, got them replaced for free thru our battery company, i cant complain about that. That was a 200.00 plus christmas bonus the battery company saved my butt

[Spinal Tap]

Nevermind, i did some research, that stancor relay is just a white rodgers 12 volt relay.
I dont think it will put out more voltage/ cause less draw to the glow plugs.

If i go with one, ill just get it at graingers

Thanks for the tip i appreciate it.

BW