Yet another noobie oil question... (1 Viewer)

[Skidpad13]

Hey folks, I know this has been asked a dozen times (or a lot more) but I've got a few noobie questions to roll into one post if you'll give me 30 seconds of your hard-fought time.

I just got a 1997 FZJ80 from another guy here in the classifieds. It's a very clean truck for its age and mileage (333K on the clock but a long list of service items and reports). It appears to have been treated very well.

Question #1: PO has used Rotella T5 15W-40 for summer weight oil & T5 5W40 for winter weight. I'm trying to coast this old girl through the winter (occasional use, not DD) until I can get her into the garage & pull the motor & trans. Is there anything you'd change or stick with this, I'm not as concerned about cost as I am about best for the engine. I've never used diesel treated oil in a gas engine so I'm asking for help on this one.

Question #2: the orange oil light lit up on the dash after I had been running at idle and a short drive after about 15 minutes (the only time I've run it since I got it last week). The manual conflicts itself on this from what I can tell. Is that light a low oil level or low oil pressure light? PO said that he had it come on before and cleaned the contact on the level sensor & it went away. I plan to check oil pressure with a gauge under the hood by removing the sending unit but wanted to get the group's two cents. The dash gauge appears to be in the correct range.

Question #3: what's the group's experience with oil treatments for an engine of this age before a full rebuild? I've researched 505CRO by ATS Chemicals and it appears fairly legit. More so than the auto zone off-the-shelf stuff anyway. I'm interested to hear your thoughts on if this is a good idea or a terrible one.

Thanks for your advice to a new LC owner, cheers!

 

[Landseer]

1. Lower "W" number is always better, 5W40 is better than 15W40. 40 is the viscosity of the oil at operating temperature and the W number is what the oil behaves like at colder temps. All oil will be more viscous than desirable when cold, but lower W numbers will be less affected. That said, it's a tractor engine, just make sure the oil is changed at reasonable intervals and you'll be fine.

2. The dash oil light is triggered by the level sensor, so low oil level. The level sender that triggers the light is know to be temperamental, definitely trust the dipstick over the oil level light.

3. I don't have any experience with oil treatments. If it were me I wouldn't bother with such things unless you have an obvious knock or similar, but thats just my 2 cents.

 

[WCBlueSky]

Some more info here:

random intermittent oil light?

Hi everyone Over the past few days, I've noticed that the yellow oil light comes on for a few seconds or maybe a minute, and then goes off. It's completely random, doesn't happen at a specific time or while I'm going around a turn or straightaway or anything, and I have no idea why it's...

forum.ih8mud.com

 

[Skidpad13]

Thanks guys, this is exactly what I thought but wanted to defer to the experience in the room. When the rebuild starts in earnest next year I'll document everything I can to give back to the group.

 

[zapatius]

If it's not smoking or anything, don't worry about oil additives. It made it 333k presumably without them.

Rotella is fine year-round since you're in Nashville. It's good down to 0 degrees according to temperature charts I've seen. If concerned, you could switch to 10W-30 Rotella for all-season. I was running Royal Purple Delvac, which is good oil. After reading technical specifications on numerous oils, I switched to 10W-30 Quaker State Ultimate Durability.

I also recommend the Motorcraft FL-1A filter. It's huge.

 

[Footwork]

Rottela 15w-40 t4. Stopped my rear main seal leak and picked up the pressure

 

[Cruzerman]

As far as planning a rebuild, don't do it if it only because of the miles. These engines can run for a long, long time. If the thing runs good, just keep doing standard maintenance.

 

[LandLocked93]

I also recommend the Motorcraft FL-1A filter. It's huge.

Does this filter have the backflow valve?

 

[Skidpad13]

It's got a motorcraft FL-1A on it now. The PO also had the head gasket done, decked, timing chain, tensioner, water pump, etc... all done in the past 24 months. He really did a bang-up job following all of the PM recommendations here on the forum. I guess I'll keep pushing forward with the other repairs. I'm an OCD type with dash warnings so I'd already gotten the ridiculously priced oil level sensor to replace the old one.

Now I get to earn my stripes by rebuilding the front knuckles & parking brake. Last thing on the list will be chasing why the center diff won't engage in 4L. I haven't done any of the FSM troubleshooting on it but have done many figure 8's down in our field.

Re: the oil pressure, it's full of oil & the dash gauge responds well to increase in RPMs so it's definitely working. Here's a shot of the dash from this afternoon showing the pressure as indicated by dash gauge alone.

 

[Skidpad13]

Also worth noting that the PO did an EGR bypass and removed the ABS module (which i do have). Everything looks good except that the ABS light stays on i assume because of the module being removed. Do you guys recommend leaving the ABS module out or reinstalling?

Thanks again for everyone's quick responses. The 1st round is definitely on me.

 

[Comet]

ABS module. Remove the light in the dash.

 

[fresnoLC]

It's got a motorcraft FL-1A on it now. The PO also had the head gasket done, decked, timing chain, tensioner, water pump, etc... all done in the past 24 months. He really did a bang-up job following all of the PM recommendations here on the forum. I guess I'll keep pushing forward with the other repairs. I'm an OCD type with dash warnings so I'd already gotten the ridiculously priced oil level sensor to replace the old one.

Now I get to earn my stripes by rebuilding the front knuckles & parking brake. Last thing on the list will be chasing why the center diff won't engage in 4L. I haven't done any of the FSM troubleshooting on it but have done many figure 8's down in our field.

Re: the oil pressure, it's full of oil & the dash gauge responds well to increase in RPMs so it's definitely working. Here's a shot of the dash from this afternoon showing the pressure as indicated by dash gauge alone.

View attachment 2827635

Is there a center diff switch on the dash? If it's not engaging in 4L but it engages with the switch the PO probably disconnected pin 7

 

[zapatius]

Does this filter have the backflow valve?

Yes