Oil pressure and blowby - related? (1 Viewer)

Spook50

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I've been noticing lately that my oil pressure when above idle is indicating between the middle line and the next line down on the gauge (FJ62). Used to be it would sit almost right at the middle line when above idle and dip down a bit when at idle. On every change I use Mobil 1 10W-40 High Mileage synthetic (6 quarts of that plus a quart of Marvel Mystery Oil, which I've done for years) and a K&N oil filter. What oil pressure are you guys seeing when driving your 62s? Just curious if I'm seeing the signs of a potential problem or if this is pretty normal for an engine with almost 300K miles on it.

I'm also noticing that my PCV catch can is filling up quicker now. Granted I'm driving a lot more (40-mile round trip to work and back 6 days a week), but even when I was active duty and driving the same distance to the base it took several months to fill up, versus the just over a month it's taking now. Am I right in thinking this is indicative of more blowby than before? Performance doesn't seem to have decreased at all, and my fuel economy is actually up from before, so I don't suspect I'm losing compression anywhere.
 
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Since no one else has chimed in... Sounds normal to me for 300K. The slight drop on the oil pressure gauge could be anything from the electrical connection at the sending unit, to increased outdoor temperature, to oil pump/relief/bearing wear. Running the Air conditioning? More load=more blow-by, higher temperature, less viscous oil=more blow-by? On the increased crankcase pressure by its self, ring wear, cylinder glaze (low load, synth oil=glaze), restricted exhaust? De-smogged, so I guess no cat?
I'll assume the jury is forever out on the use of synthetic oil in an old cast iron engine. If it were me, I'd do an oil change or two using some good ol' 10w-30, or 15-40 dino oil, and see if anything changes at all. I run "Traveler" oil (Tractor Supply store brand) I believe the formula still has (at least some of) the good stuff in it, since it still doesn't carry the "California approved" label AFAIK... My 2F likes it, my 7.3 Powerstroke likes it, and so does my Husqvarna dirtbike with wet clutches. It may be worth it to experiment with different oil, and it surely wont hurt anything to try it.
Edit: our cast iron rings and flat tappet cams do like dino oil with a fair amount of heavy metals, like tractor oil.
 
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Get a spare oil cooler banjo bolt, drill and tap it for a mechanical gauge and take note of how erroneous the oem dummy needle is...

I've done this. While I don't drive my rig much and the mechanical gage is still tie wrapped under the hood my 361k 3F sees almost 50 psi on startup. (Could be some oil passages are partially plugged on mine - shes pretty crusty in there.) The dash gage barely gets above the bottom line. Is the oil catch can stock? How much oil are you collecting.
 

OSS

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Mobil (or any motor oil company) wouldn't recommend that Marvel Mystery Oil cocktail.
Try running an oil change with 100% Mobil 10W-40 high mileage and see if anything changes.
(That Mobil oil is really good stuff)
 

Hojack

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Mobil (or any motor oil company) wouldn't recommend that Marvel Mystery Oil cocktail.
Try running an oil change with 100% Mobil 10W-40 high mileage and see if anything changes.
(That Mobil oil is really good stuff)
Mobile is awesome
I ran Marvel Mystery Oil both in the oil and fuel with the 2F. Was running a little rough and had a buddy recommend it. It smoothed out the roughness and got some more power and a little better mileage.
 

Cruiserdrew

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I will just say, that the factory gauge is a moving idiot light, and it tells you nothing.

Measure your pressure with a real pressure gauge.

But ditch the Mystery oil. What are your running that for? Just run actual motor oil.
 

Dr. John

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Mobile is awesome
I ran Marvel Mystery Oil both in the oil and fuel with the 2F. Was running a little rough and had a buddy recommend it. It smoothed out the roughness and got some more power and a little better mileage.

You'll get even more power and better mileage if you start using 0W-15 motor oil.......but for how long?
 

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