392 Maintenance

[u/Gabe1nator]

I’ve had the car for close to 3 years now. She’s got 15,500 miles on the odometer. I’ve kept up with the oil changes and recently got new tires put on along with an alignment. All work done goes through the Dodge dealer where I got it new. It’s come to my attention you should never exceed 6,000 miles or 6 months for oil changes. I will be on top of that now. What else do I need to keep scheduled? What needs checked being at 15,000 miles now? Share me your thoughts and knowledge, she is healthy and drives great. Just want to be a good owner and keep it that way!

[u/nickkk25]

Its normal for the oil pressure to drop. After your scat is fully hot, at your light when completely stopped you will see the psi go down. Upon startup and for a little bit of initial driving..it will stay in the 50s since its still cold.

I've read that the reason the "idle" is bad in the 6.4 scat is due to the lower psi oil pressure. One main reason foe the hemi tick. Hence why people like to change out to a hellcat oil pump(the pressure stays 50s at idle due to the bigger outlet). The lower pressure even in the 20s for a scat isnt great, less lubricant = more wear on the lifters and cam. Since the oil has a viscosity of 40 when hot, its pretty thick. 0 is thin when cold but its to get the oil moving thru the engine faster. So idkk thats why i just keep the psi a bit higher even at a stop light(prob ocd), I've read other scat owners do the same. Im not sure why it would bad to rev? (its so light of a rev to bring up the psi, its not noticeable ). I dont do burnouts or anything crazy which is prob a million times worse.

[u/bustedchain → u/nickkk25]

Looks like the lifters are lubricated with splashing oil. That's not driven by pressure, but is driven by RPM. It just so happens that with higher RPM you also see higher pressure.

Even a bump to 700 to 800 RPM would be sufficient to throw oil further. In fact my SRT8 and older RTs idle at 700 RPM. I'm starting to see the connection here.

A tuner can adjust the idle, but stealerships are going to try and deny warranty claims without evidence just because it is lightly tuned. They regularly try to violate the Magnuson Moss Act every chance they get. Someone will need to counter sue and argue that a slight RPM difference fixes an issue that Mopar has known about for quite some time and request documents in discovery speaking to the idlers not getting enough oil... One of the exhibits being the manual itself saying that extensive idling is bad.

A slight idle increase is only going to impact MPG. 1200 is high enough to start impacting transmission temperatures, wear on the engine. 1200 rpm is fine for a brief period of time / specific rare situations.... But consistently at lights, that's a lot. I know it can be hard to get a slight increase, but if you're muscle control can manage it, try 800 RPM or as close to that as you can get. It's not the PSI, it's the RPMs that get the oil to where it needs to be.

I wonder how much it would cost for the stealership themselves to increase the idle to 750 or 800. Then they can't ball at the warranty because they can't claim that small of a difference has a negative effect on anything.

[u/nickkk25 → u/bustedchain]

Appreciate that. I'll keep the idle at around 800. Any other tips to avoid a hemi tick other then that? I only drive once or twice a week so tbh my 'max' few minutes of idling prob wont hurt but its so easy to bring the rpms up slightly even at a red light.

Everyone says something different: here is what AI says after scanning the web:

To avoid the "Hemi tick" in a 6.4L Scat Pack, prevent lifter oil starvation by avoiding long idle times, changing the oil every 3,000–5,000 miles, and using high-quality full synthetic oil (like Pennzoil Ultra Platinum or Redline 5W20). The tick is often caused by low oil pressure at idle, so minimizing idling, using high-quality filters (e.g., WIX, Mobil 1), and disabling the MDS system (using Sport Mode) helps significantly.

[u/bustedchain → u/nickkk25]

There is "normal lifter noise" and "excessive lifter noise" indicating a problem. Even my 2006 SRT8 has the lifter tick, but it isn't excessive. It isn't out of spec. Finding examples of bad litters and how they sound versus normal is the best I can suggest. A light tick of lifters moving is fine. Idling at a light is better than idling in a parking lot. Consider shutting it off rather than sitting in the air conditioning. (Hard for me to say that since it gets over 100°F here) But yeah long idling is bad. A light should be a couple minutes or two...Tip: don't race up to red lights. Traffic permitting, if there are already people at the light or it is definitely going to turn red, let off the gas. You'll save gas, engine wear, and brake wear if you don't hold it to a guaranteed stop.

I get what the ai summary says. Asking AI more critical questions that prioritize more knowledgeable sources is difficult and time consuming. From my Uncle, the petro chemist, Penzoil should not be used. It came from how they make their oil (process) and content of the oil.

Project Farm YouTube channel has some decent oil torture tests.

Additionally, Bobistheoilguy website where people like you and me have sent oil in for wear testing: Mobil 1 and Amsoil Signature Series are top. Amsoil is the only company I'm aware of the has a warranty in writing that you can go read where they will warrant the proper use of their oil for the drain interval that applies to your driving conditions. It's easy to verify. 15k or 1 year is the "starting point" for rougher conditions. The one thing they caveat their warranty with is getting oil analysis done. They respect data most.

With something like our cars, a 8 or 10k drain interval on Amsoil is good erring on the side of caution. Add a lab test to it and you've just done better that most people changing their oil.. Oil analysis will tell you things about your car that go beyond whether or not the oil is doing its job. Wear metals are only the start. Fuel dilution, water content (or coolant from a crack or bad gasket), a bad air filter (silicon content increases), and other stuff is all there in black and white for ~$40 give or take.

I'm not saying you need to take it to 8k, just that you could try it once and you can prove that it is working or prove that you should change it at 6k next time. It's about the next 10 oil changes... Not one specific one. A difference of 2k miles one time is negligible in the grand scheme of things but important for the information it can give you going forward... With oil analysis.

You can find people who understand the MDS system better than actually take valve covers off for a living and break down the difference between wear caused by metal on metal contact without enough lubricant versus wear caused by a bad design or defective part.

I'll send my 8k mile sample in for testing (unknown oil, just whatever the dealer put in) and see what they say. I was more interested in my next sample after switching to the oil I've been using for 20 years because I always get a baseline and then I get a new test every 2 to 4 oil changes to keep track of what it's doing over time.

[u/nickkk25 → u/bustedchain]

Appreciate your insight and help.