In 30 years I've never run single-grade oil in anything but a lawnmower (and not even that nowdays), so stick with multi-grade oils.

As for the pressure numbers- those look fine. Remember that engine oil systems regulate pressure at the DELIVERY end of the oil plumbing system, so the pressure seen downstream is the delivery setpoint-pressure minus the flow loss through the system. Thicker oils have more loss due to flow resisteance, so if you look at the downstream end of the system (the bearings- where it really counts!) there comes a point where thicker oil actually REDUCES both the volume (cooling) and pressure of oil seen at the bearings. Some engines place the oil sending unit far downstream of the oil pump (example: Mopar big-block V8s where the pump feeds the passengers side front of the system, and the oil pressure sender tap point is at the rear of the engine) and you can SEE this effect on the guage to an extent. Conversely, too thin an oil will bleed out the bearing clearances too rapidly and won't fully pressurize the system.

I tend to avoid 10W40 oils because they used to require so much more viscosity modification than 10w30 or 20w50, but with today's oils that are orders of magnitude better than 80s oils (let alone 60's oils!) I wouldn't be concerned. Just don't use bargain-basement oil- go with a name-brand like Mobil, Castrol, Valvoline, etc. And I wouldn't use one of the "botique" oils that are aimed at maximizing EPA mileage numbers, either- for example that 5w20 monkey pee that Ford pushes to boost its CAFE computations just a little bit. For most of the world, 10w30, 20w50, and maybe 5w30 are fine for vintage Mopar engines. In synthetics, heck you can use anything. 0W30 Mobil-1 is a very good oil.

If you want to become a real "oil nerd" and always use the oils that are giving the very best used oil analysis results, go hang out on the www.bobistheoilguy.com discussion boards

Dude. That's not what Dan said. He said that "high mile" oil contains seal swellers. You know, the ones marketed with pictures of the odometers on the bottle?

I have taken courses on fuels and lubes put together by manufacturers (Shelloil was the biggest one I went to back in college) and that by no means makes me an expert but I know enough about additive packages. That is what high mileage oil is marketed for because that is the only significant additional property such oil can do, is to slow external leaks. Yes regular oil does do it to an extent but that's the additives doing it, not the raw non detergent oil. Try using some of that oil in your engine and see what happens.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

yes I know, it's gonna leak as if someone stabbed the motor.

No I don't know nothing about high mileage oils marketed with odometer pix. I just pick an oil, use it for 3 tops 4 months then drainit and pour new oil, filter and molykote. And mine is performance 5W40 synt, no "high mileage" oil. Manufacturer's advise is that last lets say 1.5 times regular oil, not 5 or 10x. Anyways I think I made my oil policy clear... I never ever refill, when level starts to go down I change it. That happens about 3 or 4 months after I changed oil. Let's say that I put about 3k miles over each oil change.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

I dont believe I, nor Dan are advocating high miler oils.

Let's stop fighting please.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

I'll drink to that.
I never said that yu're advocating those kinda oils, though.
For what is good, never felt any bad vibes from you, dude.

peace and love!

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

I'll drink in excess to that!

BRAP BURP

THump

zzzzzzzzzzzzzzzzzzzzzzzz

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Ha! I bet my white áss that all you were looking for was an excuse!

By the way, you missed GRÖOOK! and SPRRRRRRRRT! before ZZZzzzZZzzzzz

(according to haynes)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.