Low oil pressure

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magnummopar said:
So you are saying that Car company use 0w10 to make the engine last LONGER? Horseshit! Since when do big car company's give a damn about customers engine longevity ? They are driven by greed not building long lasting cars. In the 80's they introduced something called "planned obsolescence" When cars last over 100K miles, company's loose out on new car sales. In 70's Datsun, Toyota, Honda's would all go 200K + I dare you to try that with a Neon today, you would be lucky to make 100 without major issues. Or do they make the oil pan, intake manifold and valve cover out of plastic because it lasts longer than steel ones?
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Honestly, I have LITERALLY no idea where you're thinking the modern engines don't last as long. Not that I have too much experience with things running 0w-anything (not sure what actually specs that actually), but your engine can really last a good long time on 5W30. If your engine has good bearing clearances, there's no need to run anything heavier than 10W30 in anything.

I personally own a 2004 Chevrolet Colorado 3.5L I5. It has run regular Pennzoil 5W30 since new. It has about 112k on it and the oil comes out clean and it burns NO oil at all. My dad has a 2004 Blazer with about the same miles on it. Same oil. Also burns zero oil and the oil runs clean.

A co-worker has a 2004 Honda Accord 2.4L. 411k miles and has run 5w30 Mobil 1 since new. It has NEVER been apart. Still runs very well.

Also, you need to remember that the oil galleys are an enclosed space. When you have an incompressible fluid in an enclosed space, the pressure is the same everywhere. The oil galleys themselves and the oil is close enough to this to not make a difference.

If you loose enough oil volume the pressure will drop. That's why the pressure is actually worth something. Otherwise people would insist on installing oil flowmeters, which nobody does.

Personally, I'd like to see at least 20psi at idle, but a good first step is to dump the fram, change the oil, inspect to see if there is any metal coming out and see what happens if there isn't.

If it doesn't change, I'd personally probably pull it, but it will live for a little while.
 
RustyRatRod said:
Says who? Show me where a factory Chrysler service manual says to run 20/50 in an engine. Never have and never will. Oil viscosity has little effect on oil pressure.

A good example would be some of these newer engines where manufacturers recommend 0w20. The reason for this is to get oil to the engine QUICK on startup. Once the oil reaches operating temperature, it changes to 20 weight viscosity. They bury the oil pressure gauge cold when the oil is 0 weight.

When you spout off an opinion, make sure you let everyone know that, because to my knowledge, Chrysler never recommended 20/50 for any of these older cars. Mostly straight 30 weight and 10w30 as multi viscosity oils came into vogue. I've rarely even seen straight 40 or 10w40 recommended.

You've been watching too many Castrol commercials.

And engines don't last long anymore? Puhhleeze. What planet are you living on? Pluto?

Newer engines are lasting longer than older ones ever did and it's due in part to newer oil technology. Fuel injection also plays a role. I have seen more newer engines than I ever did old ones with 200K plus miles on them.

You are just dead wrong.
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Thank you. You saved me a lot of typing.
 
nm9stheham said:
20W-40 oil is the heaviest oil viscosity I have found yet in any Mopar FSM's of this era (but I don't have them all) and that is only for continuous temps above 32F . I would not be telling people to use 20W50 without knowing their climate and use patterns; Missouri gets waaay below freezing at times, and too heavy an oil will result in engine damage due to it not getting picked up and circulated properly at a cold start. This is even more likely to happen on an older engine that may have a worn oil pump. So, 20W-50 for the OP in this case would be a big mistake IMO. Maybe move up to 10W40, of a good grade oil.

My concern for the OP's case is that his pressure appears to have dropped as he is operating it. I would be thinking that the oil pump is well worn or the oil pressure relief valve in the pump is not closing right and allowing some pressure drop. It may also have the lighter pressure relief spring that limits pressure to 55 psi even with the pump rotors in perfect condition. I'd be replacing the oil pump as a precaution after seeing the cold and warm operating pressures drop across the broad.

BTW, I raced long distance races for years on Frams..... but am not sure I would use them now.
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'i am going to go out on a limb and assume the OP is not driving a 300+ hp rear wheel drive
light weight car in the snow. Hopefully its parked in his nice warm garage. if he has 10 psi at idle, I seriously doubt that 20w50 is going to blow his **** up, probably more likely to help it not blow up.

My advise was "My guess on 10 psi is the engine is either worn or improperly built/assembled thus meaning you risk blowing it by ignoring it. Remember,if its 10psi at gauge, one of the first passages from the pump exit, its not going to be that much in the passages in rod journals of the crank at front of the block. My opinion of course."

In the days of old, the oil of choice was Valvoline 20w50 Racing oil. If you dont remember it, ask somebody over 40, they will. It was what we ran.
 
goldduster318 said:
Honestly, I have LITERALLY no idea where you're thinking the modern engines don't last as long. Not that I have too much experience with things running 0w-anything (not sure what actually specs that actually), but your engine can really last a good long time on 5W30. If your engine has good bearing clearances, there's no need to run anything heavier than 10W30 in anything.

I personally own a 2004 Chevrolet Colorado 3.5L I5. It has run regular Pennzoil 5W30 since new. It has about 112k on it and the oil comes out clean and it burns NO oil at all. My dad has a 2004 Blazer with about the same miles on it. Same oil. Also burns zero oil and the oil runs clean.

A co-worker has a 2004 Honda Accord 2.4L. 411k miles and has run 5w30 Mobil 1 since new. It has NEVER been apart. Still runs very well.

Also, you need to remember that the oil galleys are an enclosed space. When you have an incompressible fluid in an enclosed space, the pressure is the same everywhere. The oil galleys themselves and the oil is close enough to this to not make a difference.

If you loose enough oil volume the pressure will drop. That's why the pressure is actually worth something. Otherwise people would insist on installing oil flowmeters, which nobody does.

Personally, I'd like to see at least 20psi at idle, but a good first step is to dump the fram, change the oil, inspect to see if there is any metal coming out and see what happens if there isn't.

If it doesn't change, I'd personally probably pull it, but it will live for a little while.
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"If your engine has good bearing clearances" , I agree completely, BUT OP has 10 psi at idle, so my guess is he DOESNT have good bearing clearances or he would have better oil pressure. The recommendation of 20w50 was to TEST the oil system and help determine if a possible problem exists. According to RustyRat, I am a dumb *** because according to him, viscosity has no effect on oil pressure and 5wwhatever gets to bearings faster...I dont agree.

Many racers used to run "loose" engines ie extra clearance in main and rod bearings then make up for it with heavier oil, allowing the engine to free rev quicker, they also ran 30-40 at idle and 80 at rpm.
 
Goldduster, throwing an example of high mileage engine running synthetic is not what we were discussing nor are RARE examples relevant.

"A co-worker has a 2004 Honda Accord 2.4L. 411k miles and has run 5w30 Mobil 1 since new. It has NEVER been apart. Still runs very well."

" Personally, I'd like to see at least 20psi at idle, but a good first step is to dump the fram, change the oil, inspect to see if there is any metal coming out and see what happens if there isnt"
Is that not what I suggested? I also said to use a heavy oil to help diagnose a potential problem.

I had a 1973 K5 blazer 350 with 275K on it, do you expect your Colorado to get that far?
 
I was talking to a guy today at church that bought a Ram truck and lifted it. he says his oil pressure light flickers at idle. I asked what the oil pressure was and he says its 0 on the gauge n a cold start but after a second start it pops up to normal. He stated that his manual says 4psi at idle! Man, that seems low but what do I know about EFI Magnums?
 
magnummopar said:
'i am going to go out on a limb and assume the OP is not driving a 300+ hp rear wheel drive
light weight car in the snow. Hopefully its parked in his nice warm garage. if he has 10 psi at idle, I seriously doubt that 20w50 is going to blow his **** up, probably more likely to help it not blow up.

My advise was "My guess on 10 psi is the engine is either worn or improperly built/assembled thus meaning you risk blowing it by ignoring it. Remember,if its 10psi at gauge, one of the first passages from the pump exit, its not going to be that much in the passages in rod journals of the crank at front of the block. My opinion of course."

In the days of old, the oil of choice was Valvoline 20w50 Racing oil. If you dont remember it, ask somebody over 40, they will. It was what we ran.
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I just remember in 1978 turning a rod bearing on an engine with a weak oil pump by putting 20W50 in it just before the next race. (Valvoline or Kendall, I can't remember for sure.) It was a 120 HP 4 banger with a gear type oil pump. It never picked up on the first start up after the change, and the temp was a nice springtime 70 F. So that is why I question the suggestion of 20W50 with an engine in unknown condition and in cold temps: if a worn pump is the issue, then the heavy weight IS indeed a risk.

TO the OP, for minimizing risk in your situation, and assuminng the filter brand change does nothing, my approach would be to pull the oil pump. You can examine the clearances in the pump per the book, and if worn, then you know there is an issue in the pump. If the pump is good on clearances, then you know that either pressure relief valve in the pump is acting up and lowering your oil pressure, or you indeed have worn bearings.
 
magnummopar said:
Remember,if its 10psi at gauge, one of the first passages from the pump exit, its not going to be that much in the passages in rod journals of the crank at front of the block. My opinion of course."
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g49bridges said:
Its a mechanical gauge. Not a high end gauge, but I swapped it out for another one I had in the shop and it read the same. So I'm guessing the gauge is right. Bearing clearances being a little loose is a possibility. Engine did see the track quiet a bit before I got it.
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so, this has got me curious, you mention the gauge will read optimal, because it is on one of the first passages, before pressure drops due to restrictive passages

now, the OP mentions this is a mechanical gauge, this most likely means he is using some 6 feet of 1/8 nylon tubing

would that at all change your perception of difference between oil pressure at the gauge, and oil pressure at say, the #1 main ?
 
There is no flow to the gauge after the system pressurizes. So there is not any pressure drop in the line from the block to the gauge.

The pressure drop to the #1 main relative to the oil pressure gauge is caused by:
- drops though the length of the passenger side oil gallery due to the feeds to the other mains, the rockers, and any leakage through/past the passenger side lifters
- the flow from the #1 main to the #1 rod bearing and #1 cam journal
- and, probably most of all, the flow that runs from #1 main up to the driver's side oil gallery.
 
PSI is a direct relation to back pressure within the system. If the pressure is low the clearances are probably a bit more opened up than new. Not saying it's bad. As engines get more use they wear in the bearings and such. No biggie. Run the oil for your climate is one of the most important things you can do! To heavy an oil in cold weather and the pump has to fight to pick it up causing starvation. The whole thicker is better and more psi is hogwash. I ran straight 40 wt in my 340. Mind you it was an 11:1 solid cammed monster. But that was San Diego weather where temps averaged in the 60 winter and 95 to 110 in the summer months. Mine had anywhere from 8 psi at idle to 65 at 7000 rpm. Never lost a bearing. (broke the block but that's another story lol) If your that worried about the pressure pull the pan and check the clearances. If they are within spec and your not going to hammer on the engine constantly screw back together and run it. If your sustaining 5000 rpm and up constantly then yes fix your pressures. (any number of things contribute to this)

Some one mentioned newer engines don't last? 174,000 miles on my 2004 GTO and I've not been easy on it begs to differ!!!!! (all aluminum push rod v8!) I run Lucas synthetic racing oil in it in the correct viscosity. I tried Royal Purple in it once and the engine developed a lifter noise. Immediately drained the RP out and found the Lucas at another store and the noise went away. Wierd....

Won't run Mobil one in my engines but that's just my preference. I did have an issue with Fram filters and their lack of quality control. Won't go back PERIOD!

I've had good luck with K&N oil filters in my GTO. I use Wix in my Dart. Factory filters in my 2015 Duramax. Ford filters when I had my 2011 Ecoboost. I believe all NAPA filters are Wix and are good quality filters for a decent price. Harder on your engine, change your oil more often. Especially when carbed.

Some of this is opinion based and some experience based. Do your research and judge for yourself.
 
O weight oil is used to get MPG up. It does flow faster in cold weather, BUT these engines are engineered to use this weight oil. VERY close tolerance in bearings. And the plastic intake is very useful, lighter for one, and it makes more power then aluminum, it stays cool. The rest of the plastic is there to reduce weight to get mandated MPG. I think OP could rebuild that engine but more then likely, it will last a long time as is. And one more thing, you do realize most new cars dont have a oil pressure gauge? I think people would be scared to see how low oil pressure is in these engines.
 
I completely forgot that the gauge doesn't drop due to "bleed" like the journals

makes sense now
 
Mopar Tim said:
O weight oil is used to get MPG up. It does flow faster in cold weather, BUT these engines are engineered to use this weight oil. VERY close tolerance in bearings. And the plastic intake is very useful, lighter for one, and it makes more power then aluminum, it stays cool. The rest of the plastic is there to reduce weight to get mandated MPG. I think OP could rebuild that engine but more then likely, it will last a long time as is. And one more thing, you do realize most new cars dont have a oil pressure gauge? I think people would be scared to see how low oil pressure is in these engines.
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Tim I was going to stay out of this from my last post but this is incorrect. The first number in a multi viscosity oil is the weight the oil is when it is cold. Not cold weather, but when the oil is below normal operating temperature. After the oil reaches normal operating temperature, then it changes to the second number, so 0w20 weight is 0 weight when cold and when it reaches operating temperature it is 20 weight.

If what you said about mileage were true, it would need to be 0 weight all the time, not just when cold.

The reason we are seeing all these really low cold operating weights is so that the engine can get the light weight oil pumped through it very quickly to help avoid oil starvation on startup. That's all.

I've had enough of the bickering. It's getting the OP's thread off base. So yall can keep on arguin. I am done.
 
Apparently some people are not reading all the posts or not carefully. I recommended the 20w50 to TEST the engine and determine if it needs to be taken apart and inspected. Its an UNKNOWN engine so original owner might have drilled gallery plugs by timing chain, sloppy clearance, worn pump or who knows. By using a heavy oil, OP will be able to tell more about whats going on in engine without dis-assembly. If pressure goes to 20 at idle than we could assume wear or loose clearances, not spun bearing, drilled plugs etc. If nothing changes, I would think that it means there is a potential problem.

I would not recommend running 20w50 in a car parked outside in -10 weather, but I was also assuming the OP was not going to change his oil in a snow bank either. It would not harm his engine to swap oil and fire it up to check. If its garaged, it wont hurt it to keep it in there either.

So many people offered their opinion, like myself, but it seems there is no point to continue to share mine as several posters have stated I am wrong. Nobody that said anything against my theory answered any of the questions I asked, nor has Rusty(either one) said anything about the ridiculous statements they made. If you dont know what psi stands for should you even give an opinion? you are so sure that the engine is "fine" but have no info to back your opinion except a low pressure engine you own.

Just for fun, I went and started our 69 HT 318. It has over 170K and smokes a bit on start BUT has 20+ at idle and 60 at rev.

This thread was started to help make a decision about OP's engine. We can offer examples of what we have/had but stories of 400K hondas or cars run on synthetic do nothing to help OP make a difficult choice, run it and risk possible damage or tear it apart, possibly for no reason(others opinion). I have seen engines run for long time on 30w and engines with 10 psi at idle, but its a 340, not a pinto so I think it would at least be worth $20 to OP to determine issues or lack thereof without tearing it down.

OP if you do try 20w50, assuming you are not scared of others BS, please do not store oil in freezer or snow bank prior to pouring in engine. If its at room temp it will hurt nothing. I can offer some form of proof in that products like Power Punch or Lucas Oil treatment etc are VERY heavy viscosity and they wont "blow up" your engine when you put it in your oil. It will however, RAISE your oil pressure at least temporarily. Feel free to chime in anybody that has ever put this in an engine before....according to Rusty, viscosity has no affect on pressure, but then he also thinks Pluto is a planet and psi is "per square inch". Your engine, your choice. Remember, dont believe everything you read on internet, probably 80% is pure BS.
 
Like I said, if you want to argue about oil, and it certainly seems you do, please start another thread. I will gladly participate. But our arguing has gotten the PO's thread completely off base.
 
RustyRatRod said:
Tim I was going to stay out of this from my last post but this is incorrect. The first number in a multi viscosity oil is the weight the oil is when it is cold. Not cold weather, but when the oil is below normal operating temperature. After the oil reaches normal operating temperature, then it changes to the second number, so 0w20 weight is 0 weight when cold and when it reaches operating temperature it is 20 weight.

If what you said about mileage were true, it would need to be 0 weight all the time, not just when cold.

The reason we are seeing all these really low cold operating weights is so that the engine can get the light weight oil pumped through it very quickly to help avoid oil starvation on startup. That's all.

I've had enough of the bickering. It's getting the OP's thread off base. So yall can keep on arguin. I am done.
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makes perfect sense, Thanks.
 
Interesting debate.
I would add the the anti drain back valve additionally protects engine from "dry" start up effectively keeping the filter primed. This of course is most important when the filter is mounted horizontally , or inverted as is the slant six engine.
 
Although its still within spec, for reference my 360 makes about 75 cold and 35-40 at hot idle, and 60 psi when cruising over 2k RPM with 20-50. But it has 2 thou bearing clearances and pressure fed solid roller lifters so that bleeds off some pressure.
 
magnummopar said:
Goldduster, throwing an example of high mileage engine running synthetic is not what we were discussing nor are RARE examples relevant.

"A co-worker has a 2004 Honda Accord 2.4L. 411k miles and has run 5w30 Mobil 1 since new. It has NEVER been apart. Still runs very well."

" Personally, I'd like to see at least 20psi at idle, but a good first step is to dump the fram, change the oil, inspect to see if there is any metal coming out and see what happens if there isnt"
Is that not what I suggested? I also said to use a heavy oil to help diagnose a potential problem.

I had a 1973 K5 blazer 350 with 275K on it, do you expect your Colorado to get that far?
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Actually I do expect it to go that far. At the rate I drive it anymore since it's not my primary vehicle, it may take 20-25 years to get there. I see these trucks all the time at over 200k that weren't as well taken care of as mine is. You made the claim that they don't last as long anymore which is totally baseless...unless the only engine you've ever seen with EFI is a 2.7 intrepid engine.
 
Good thing I have never seen a Taurus, Hundai, Toyota Tercel, Mazda 2200, anything Mitsubishi, Neon, Civic, etc. You are correct, I am just making it up to look like a dumb ***. I have never worked on cars before so I dont know ****.

OP go ahead and put 10w30 in it, drive it hard and if it eats itself you can blame the "expert" advise you got from guys that might be a plumber, waiter or maybe a gas station attendant. I certainly havent seen anybody claiming to be a professional mechanic respond. I even asked but got no answer. Its pretty easy to be an arm chair quarterback!

Anybody else with with a shop or professional experience care to chime in?

At least now you know what oil to run in your 5 cyl GM, Honda or Blazer :D
 
I use Mobile 1 20/50 in all my old cars. 67 440 GTS Dart, 66 426 HEMI charger, and my 66 273 Charger Dart, still being worked on. I Built all of my cars. Just had machine work done, BUT I assembled all myself. Dont need to own a shop to know what is what. But I did turn wrenches at a GM dealer.
 
Mopar Tim said:
I Built all of my cars. Just had machine work done, BUT I assembled all myself. Don't need to own a shop to know what is what.
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Thank you, MT.

I guess we should all consult my acquaintance who is Prius mechanic on this matter since he is a professional mechanic.#-o
 
That's because people who have done it for a living don't need to blow their own horn. I have been turning wrenches professionally since 1974. I was nine. I was the youngest Master ASE technician in Georgia before I graduated high school in 1983.

That said, I have seen certified professional mechanics that couldn't find the right tool for a job and some shade trees that would put any professional to shame, so all of that is irrelevant.

This discussion about oil has zip to do with whether someone is a professional mechanic or not. It has to do with motor oil.

So, again, if any of you want to chest thump, argue about oil or whatever else, can we please take it to another thread? Thanks.
 
This discussion about oil has zip to do with whether someone is a professional mechanic or not. It has to do with motor oil.
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Yep. RRR I have never met you but I can tell you are a hell of a mechanic. No chest thumping here....
 
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