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

7K views 35 replies 12 participants last post by  '01SilverBullet 
#1 ·
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
 
#2 ·
I've never heard of 10w40 Rotella? I've only seen the 5w40,10w30, and 15w40? :dunno: Anyways, have you checked to see if your glow plug relay is still putting out a good voltage?
 
#3 ·
never heard of any1 using 10w-40...i use Amsoil 5w-40 all year long in my 6.0L !!!
 
#4 ·
Hey thanks for the replys guys.... I screwed the pooch on that one, you guys were right. 10w30:eek:

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?
 
#6 ·
You can ohm the glowplugs with a multi meter without removing them. Search for it on here.
 
#7 ·
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
 
#9 ·
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:thumb:
 
#10 ·
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:thumb:
 
#12 ·
A lot of people on here swear by the Stancor relay, I'm going to test mine (stock, I assume) next time I pull it in. From what I've read, the Stancor does a much better job than stock of handling the high amperage the glow plug circuit sees.
 
#11 ·
If it's 20 degress outside then plug the truck in at night. Mine gives me problems starting sometimes when it's under 30 degrees for several hours at a time, and I don't use the block heater.

Just plug in the truck and use the recommended 15W-40 that the 7.3L calls for. You'll be fine.......
 
#13 ·
There is absolutely nothing wrong with 10w-30, its in your owners manual as an approved viscosity. I use it in my '89 IDI and my '07 6.0 year around with zero issues.

If anything it should be starting faster than with 15w-40, by the way the cold flow of 10w-30 and 5w-40 are almost identical.
 
#14 ·
I had the same starting problem and went through two stock relays then went to the Stancor I haven't had a problem starting since. If you have to plug it in at 30 degrees there is something wrong cold doesn't start until 0. I don't worry about plugging my 7.3 in until the forecast says its gonna be below 10 if its not plugged in and its above ten or so it starts fine might be a cold running ***** for a few minutes but she fires right up. Go with the Stancor its the best. Go to Google and put in Stancor relay 586-902 that's the one. Let me know.
 
#16 ·
Yeah, thats why i added a little lower viscosity oil this winter, i was wanting thinner oil so it would start better. I dont plug it in. NEVER. It does get to about -10° here, but it starts without ether.

The truck starts fine, it just seem to crank longer once i thinned out the oil a little. It has brand new batteries, i guess ill look at the glow plugs this weekend and see if they are within spec. I found that the stock glow plugs are not the best, and this truck has stock replacements.
Guess i will spend some money on the truck to make it thru the winter, i hate spending money.
Any idea how many amps those 8 glow plugs pull? That relay yall are talking about is 200 amp draw capacity. Wished the contacts in it were rebuildable like the ones at work for 24 and 48 volt on elec booms. Those contacts are about 7.00 to rebuild and the coils never fail.
 
#21 ·
The only oil cap I ever saw with 5W-40 on it was on 4 cylinder imports. Well, maybe on some domestic 4 cylinders too. You wouldn't think that it matters given the advice that many here are giving you, but I always thought our trucks and most diesel trucks in general called for 15W-40?

I haven't had an owner's manual for my truck in years and I need to go and buy one and see what the colder months call for but I'm thinking 5W-40 is NOT one of the recommendations in the manual. I could be wrong.....

Anyway, let's say it's ok to run 5W-40, and I know that alot of people do this already. Why would you change the oil to start quicker instead of just plugging the truck in?

I know lots of people get colds starts and "romps" out of their 7.3L when they don't plug in during that cold of weather. Diesels do like heat to operate properly.......more so than gas engines do.
 
#23 ·
My 02's owners manual does not list 5w40 mainly cause they were not popular back then. I have 15w40 preferred over 30* and 10w30 preferred under 30*. However in my 2004.5 dodge 5w40 could be use from -30 to 100+ and my understanding is it is referenced in the 6.0 manual. So long as it is a CJ-4 oil for the most part, International and Ford should be kosher with it.


In the past 10-15 year people run 15w40 cause it is typically the cheapest diesel grade, it wasn't THAT long ago that SAE 30 weight was the standard diesel oil.....imagine starting that in the cold...ekkks.
 
#22 ·
5w40 rotella t might not be in the ford book but it meets and exceeds the oil recommended by ford. Would you rather have a huge electric bill from plugging in your block heater every night or spend the cash for a oil that many swear by in cold areas. I never plug in my truck she fires right up no romps at all only time I ever had romps was with 15w40.

Sent from my ADR6350 using AutoGuide.Com Free
 
#25 ·
I run 15W-40 in it year round, because that's what we already have in bulk...lol. If it's cold, I simply plug it in for a few hours before I take off, via a timer.
 
#26 ·
I've been using a timer as well. 3 hours is all our trucks need when plugging in. And that's on the nites that they need plugging in when and if the truck is needed the following morning. I plug in on cold nights about 3 times a week. So it's not like I'm shutting down my local grid just to plug in at nite

Shell 5W-40 is only available in full synthetic right? Full synthetics are cheaper than regular dino oil still..... aren't they?

I'll just keep starting my truck on warm 15W-40 and everyone else can start theirs on cold 5W-40. I'm not feeling it though.

I still always thought diesels did better with heat, but now I'm wondering why Ford even put block heaters on our trucks to start with:dunno:
 
#27 ·
Shell 5W-40 is only available in full synthetic right? Full synthetics are cheaper than regular dino oil still..... aren't they?
Not even close, Rotella, Delo and Delvac 15w-40 (the big three of oils) are all about 12-14 bucks a gallon at wally world, Rotella 5W-40 is like 22 a gallon and Mobil 1 is a ridiculous 28 bucks a gallon. Rotella T5 10w-30 blend is 16, I run that. Kinda a happy medium, I also never plug my truck in, no outside outlets on my house.
 
#30 · (Edited)
I don't think 5W-40 HDEO synthetic was in production when our 7.3L were being produced was it? Anyway! Times have changed... It has been proven that the 7.3L and 6.0L shear the 40wt oil down to a 30wt over time... But... No further... These HEUI injectors really like a 30wt...

My 7.3L has 289K miles her and she reacts so differently with T5 10w-30... Never a Romp...Quieter+Smoother Idle... Major difference is throttle response...

I pour in a mix of 2gallons T5 and 2gallons T6 5W-40... Local Walmart sells T5-$16 and T6-$21 I run this mix yr round... As well as tow our 11Klb 5th wheel during the summer months... My 5K mile UOA come back stellar every time... Polaris tells me I can go to 7K if I like...

I will also say this... I work 12hour shifts... During the winter months those nights get down around 20*F sometimes colder... I plug my 7.3L in every time... After sitting for 12hours... She starts so fast and smooth.... Even If I don't plug her in the difference is night and day with the T5-T6 mix compared to the 15W-40...

After I left a qt of Delo 15W-40 out over night @ 16*F... The next day... I tryed to pour that same oil into a gal jug just to see the thickness I was dealing with... After I stood there for 5 min waiting for just half the oil to slowly pour out... I chose right there never to run 15W-40 again in the winter months...

Granted my 7.3L doesn't get plugged in all the time @ work during our night shift turn around due to there are only 4 outlets to use... But with the T5-T6 mix my 7.3L still fires right up and never romps...

The reason I use the T6 is its a more robust oil compared to the T5 and I wanted that little bit more added protection-{Anti Wear Additives}... Why? Because it's my 7.3L with 289K miles...

Most of the time Change is for the better... Some people handle it better then most... I just listened to my 7.3L before and after the switch to the lower viscosity oil and that was all it took...

Alot of good advice though out this thread...

Just a note: Some owners don't have the luxury of plugging in their trucks at work or maybe even at home... Pouring in either 5W-40 HDE0 or 10W30 HDEO will help with those very cold start-ups... As long as everything else is in good working order... The quicker that oil gets to those moving engine parts the less wear occurs...
 
#31 ·
Yes. The sarcasm was meant to be broad on the whole topic of running thinner weight oil, and it was never directed at any one specific person.

Anyway, after further reading, I am thinking that better throttle response would most likely yield better fuel mileage too, right?

No sarcasm meant. Seriously, I might consider a 10W-40. Rotella has a 10W-40 that is also a T-5 don't they? Better mileage is something I would definitely do. Cos' I could still plug my truck up.

Syn, when you mix your oil, does it average out the weights? In other words would the 10W-30 and 5W-40 make it more like a 7.5W-35?
 
#34 · (Edited)
At the time of the my winter oil change... And WM is the only place that stocks the T6 in my town... And the stuff is always out of stock on the shelf... when I went to WM... they only had 2 gallons left... and 6 or 7 gallons of the T5... So I really had no choice... Mixing these 2 will not harm anything... I have had to do it several times in the past due to out of stocks... The UOA came back looking good @5k miles...

If I was smart I would just buy a gallon every time I am in WM... {If in Stock}...But most of the time we are in a rush... and I forget about it...

WM needs more shelf space for the T6... This is the reason.

E: MPG increase? No idea... never payed attention... If my 01 had one of those fancy MPG calculators installed I might have an answer for ya... Auto manufacturers have jumped on the 5W-20 bandwagon to help with MPG... Maybe dropping down to a HDEO 5W-30 or 0W-40 would help some... I really don't think a 10W-30 or 5W-40 will show that much of an increase to prove anything...I really don't know... I just know dropping viscosity from 15W-40 to 10W-30 or 5W-40 made a big difference in my 7.3L... Just remember {Every} 7.3L or 6.0L is different and will have different results...
 
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