Oil pressure Inline 6

[JG2020]

Fram filters are called "the orange can of death" for a reason. I use Motorcraft filters.

I'm not saying that is your problem, but it might make a difference. So I'd change it and see if there's a change.

100% change the filter for anything but a "orange can of death"!

When I had the oil changed on my 02 Dodge from a quick change place a short time later I had the same issue, low oil PSI.

When the dealer did the oil change and used a different filter never had that issue.

I go with NAPA gold filters on my pick up.

Pick up a good filter and 1 qt oil. change the filter and add the oil and you should be ok.

Dave ----

Hi,

I changed the filter and added new oil back to the fill mark.

I get 55psi on startup. I took a 45 minute drive and I got about 23 PSI at 1800 RPM and 65 MPH

At idle I was between 10-12 PSI. This was on a cooler day about 65 degrees

Helped my son move out his storage unit yesterday. It was about 93 degrees out. 50 minute drive each way.

Startup at 55 PSI again, around 20psi at 45 to 55 MPH

At stop lights I was dropping to 8 PSI and at one point down to 5PSI and low on the stock gauge. A little tap on the gas and it shoots up to 20-24PSI then drops low again.

Shell Rotella T4 Triple Protection Conventional 10W-30 Diesel Engine Oil

Thanks!

Josh

[JG2020]

Hi,

I changed the filter and added new oil back to the fill mark.

I get 55psi on startup. I took a 45 minute drive and I got about 23 PSI at 1800 RPM and 65 MPH

At idle I was between 10-12 PSI. This was on a cooler day about 65 degrees

Helped my son move out his storage unit yesterday. It was about 93 degrees out. 50 minute drive each way.

Startup at 55 PSI again, around 20psi at 45 to 55 MPH

At stop lights I was dropping to 8 PSI and at one point down to 5PSI and low on the stock gauge. A little tap on the gas and it shoots up to 20-24PSI then drops low again.

Shell Rotella T4 Triple Protection Conventional 10W-30 Diesel Engine Oil

Thanks!

Josh

Any comments on these readings?

Thanks!

[ArdWrknTrk]

Any comments on these readings?

Thanks!

It just sounds like you have some bearing wear in your engine.

5w/30 or 10w/30 won't change how thick the oil is at operating temperature.

The W (winter) represents how vicious the oil is when cold, the second number is how thick it acts at operating temperature.

It's been a long time since I followed the SAE ratings but I believe those numbers are for 0 and 100°C, or 32 and 212°F

The W number is only going to effect how quickly the oil flows to the bearings in a cold engine.

The second number is going to effect how easily it passes through and out of the bearings when the engine is warmed up.

Also remember that engines loosen up as the metal heats up and expands.

So you're almost always going to see some drop in oil pressure as the oil thins and the clearances increase.

You could try adding some viscosity index improvement additives like Motor Honey or STP and see if that helps.

Or you could try an oil with a high rating of 40 or even 50 the next time you change your oil.

[Gary Lewis]

It just sounds like you have some bearing wear in your engine.

5w/30 or 10w/30 won't change how thick the oil is at operating temperature.

The W (winter) represents how vicious the oil is when cold, the second number is how thick it acts at operating temperature.

It's been a long time since I followed the SAE ratings but I believe those numbers are for 0 and 100°C, or 32 and 212°F

The W number is only going to effect how quickly the oil flows to the bearings in a cold engine.

The second number is going to effect how easily it passes through and out of the bearings when the engine is warmed up.

Also remember that engines loosen up as the metal heats up and expands.

So you're almost always going to see some drop in oil pressure as the oil thins and the clearances increase.

You could try adding some viscosity index improvement additives like Motor Honey or STP and see if that helps.

Or you could try an oil with a high rating of 40 or even 50 the next time you change your oil.

I agree with all Jim said.

In addition, I don't think you have anything to worry about. Yes, the pressure is low when at hot idle. But assuming the 300 six is like the V8's where the oil pressure pickup point is at the end of the chain, you have enough pressure to the bearings to ensure they are lubricated. It isn't the pressure that creates the wedge of oil that keeps the crank from the bearings, but the presence of oil. So if you have 5 psi after all of the bearings and the lifters then you won't have problems.

No, it isn't a new engine with tight tolerances in the bearings that create high pressure in the oiling system. But it will work just fine.

[Rembrant]

I agree with all Jim said.

In addition, I don't think you have anything to worry about. Yes, the pressure is low when at hot idle. But assuming the 300 six is like the V8's where the oil pressure pickup point is at the end of the chain, you have enough pressure to the bearings to ensure they are lubricated. It isn't the pressure that creates the wedge of oil that keeps the crank from the bearings, but the presence of oil. So if you have 5 psi after all of the bearings and the lifters then you won't have problems.

No, it isn't a new engine with tight tolerances in the bearings that create high pressure in the oiling system. But it will work just fine.

The oil pressure reads fairly low on my 300 inline 6, but I read a comment online the other day that said for the 300, as long as the gauge is showing "any pressure at all", that it is enough...LOL.

[Rembrant]

The oil pressure reads fairly low on my 300 inline 6, but I read a comment online the other day that said for the 300, as long as the gauge is showing "any pressure at all", that it is enough...LOL.

Here is where mine sits when it is fully up to operating temp. A bit hard to see, but I'd say the needle is on the high side of the "N". When it is cold it reads in the middle, or a hair beyond...but once hot it drops way down to where it is in this picture. Running 15w40 currently. I have no idea what that pressure actually is...but the engine runs really smoothly and quietly. I know in the middle of the factory gauge is around 55psi? I'm maybe at 20psi at my low point? I know my 302 runs around 55psi when hot (according to my dyno day) and it reads in the middle of the factory oil pressure gauge.

[JG2020]

Here is where mine sits when it is fully up to operating temp. A bit hard to see, but I'd say the needle is on the high side of the "N". When it is cold it reads in the middle, or a hair beyond...but once hot it drops way down to where it is in this picture. Running 15w40 currently. I have no idea what that pressure actually is...but the engine runs really smoothly and quietly. I know in the middle of the factory gauge is around 55psi? I'm maybe at 20psi at my low point? I know my 302 runs around 55psi when hot (according to my dyno day) and it reads in the middle of the factory oil pressure gauge.

Thanks everyone! Puts my mind at ease a bit. It's nerve wracking when sitting at a light and the pressure gets that low and I am waiting for a loud bang or the like!

So the Motor Honey etc is a safe additive? I always feel cautious of these products. I do use Lucas in the gas. And I added about 5 ounces of Marvel Mystery Oil on the last oil change.

The truck has been running good and I have lot's of elbow grease invested already with more projects in the works. I still smile every time driving down the road in an old truck!

 

[ArdWrknTrk]

Thanks everyone! Puts my mind at ease a bit. It's nerve wracking when sitting at a light and the pressure gets that low and I am waiting for a loud bang or the like!

So the Motor Honey etc is a safe additive? I always feel cautious of these products. I do use Lucas in the gas. And I added about 5 ounces of Marvel Mystery Oil on the last oil change.

The truck has been running good and I have lot's of elbow grease invested already with more projects in the works. I still smile every time driving down the road in an old truck!

I've used STP as both a viscosity fortifier and an assembly lube.

It has been around much longer than I have and don't see it demonized, generally.

While I'm not a fan of 'snake oil', you seem to use Lucas products and they're no different.

I grew up close to MMO, and understand what it is and why I would want to use it (or not)

If anything I'd say putting the detergent and salicylic acid in with your oil change has started to free up a bunch of varnish and that is why your pressure reads lower now.

 

[JG2020]

I've used STP as both a viscosity fortifier and an assembly lube.It has been around much longer than I have and don't see it demonized, generally.While I'm not a fan of 'snake oil', you seem to use Lucas products and they're no different. I grew up close to MMO, and understand what it is and why I would want to use it (or not)If anything I'd say putting the detergent and salicylic acid in with your oil change has started to free up a bunch of varnish and that is why your pressure reads lower now.

Thanks. I am not a fan of additives in general either. My friend was a head mechanic for all ground vehicles at Newark airport and he swore by Lucas. 

 

 

But who knows ? The truck was pretty abused so I thought giving it some extra meds for the first couple of thousand miles would be good. 

 

 

Prob the best course is to run it the way it was meant to be. 

 

 

 

 

 

On Thu, Jun 10, 2021 at 10:14 AM ArdWrknTrk [via Bullnose Enthusiasts Forum] <redacted_email_address> wrote: