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Discussion Starter #1
While sitting idle the other day in my '95 wagon, the oil light began to flash. It would go away when I revved, then came back on steady while idling. I drove it home, it went off and it didn't come on the whole way. The oil level is perfect.

Is the oil light (oil can diagram) for low level or low pressure or both? How do I diagnose?
 

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Is the oil light (oil can diagram) for low level or low pressure or both? How do I diagnose?

The Low Oil Level light is connected to the PCM which is connected to the switch in the pan. It is separate from the oil pressure gauge.


If you have a stock car the oil gauge is connected to a low oil pressure switch. If it has been changed to the 9C1 pressure sensor you have a real gauge.


Checking the oil pressure with a mechanical gauge is the best way.


If you want to throw parts at it a new switch or sensor would be the other way.
 

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Discussion Starter #5
Where do you hook up the pressure gauge? What should the pressure read?
 

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Where do you hook up the pressure gauge? What should the pressure read?
there is a NPT thread plug above the oil filter you can attach a OP gauge to if it has a 1/8" NPT fitting. Typically OP gage has a short hose on them so you would have to read the gauge from under the car while someone revs the motor once it is warmed up.

You can also tap into the same fitting the OP sensor is on rear DS of motor but that is hard to access

20 psi at idle warm engine and 50 psi at high rpm would be good. Opinions say as little as 10 psi at idle as long as it hits at least 40 psi on higher rpm's

with that said your sig says the wagon has 300k mi on it.....if true the motor is quite high mileage which would be normal for having low oil pressure because the bearings are worn.

A thicker weight oil (10-40 or 20-50) would be a band aide to help increase oil pressure with worn out bearings
 

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there is a NPT thread plug above the oil filter you can attach a OP gauge to if it has a 1/8" NPT fitting. Typically OP gage has a short hose on them so you would have to read the gauge from under the car while someone revs the motor once it is warmed up.

You can also tap into the same fitting the OP sensor is on rear DS of motor but that is hard to access

20 psi at idle warm engine and 50 psi at high rpm would be good. Opinions say as little as 10 psi at idle as long as it hits at least 40 psi on higher rpm's

with that said your sig says the wagon has 300k mi on it.....if true the motor is quite high mileage which would be normal for having low oil pressure because the bearings are worn.

A thicker weight oil (10-40 or 20-50) would be a band aide to help increase oil pressure with worn out bearings
I'd agree if you have stock exhaust manifolds it's very easy to gain access to the plug on the side of the engine block above the filter. I used to have my gauge plumbed in through there until I installed headers.

BALLS made another good suggestion about oil pressure and oil viscosity. I see typically 14 PSI hot @ around 650RPM using Castrol 10W/40 oil. 10W/40 brought up the PSI approximately 2-4 from 10, when I previously ran 5W/30.

I may just for shiz and grins try using 20W/50 next time to see where the pressure goes, especially since my climate is super hot for most of the year.
 

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Oil pump will sure get a workout trying to pump 20w50 through an LT1,unless it is totally wore out...
 

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OP's 300k mi motor would be on the "worn out" side. The oil light flicker would be a indication Oil Pressure is dropping below 5 psi at idle.

Using a higher weight oil would be a way of getting more life out of its worn bearings

This assumes his oil pressure sensor is reporting correctly

short of using a mechanical gauge to check Oil Pressure....OP could go 10-40 or even 20-50 to see if that stops the oil light "flicker" at idle

20-50 wt oil is used in motors built with wider bearing clearances. Not all that uncommon on rebuilt performance MOTORS
 

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Exactly. Do not run 20w-50 oil in your LT-1. How hot was your engine when this occurred? What weight oil are you currently running?
 

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BTW, I have 400,000mi and still run 5w-40 synthetic with no pressure problems.
 

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Discussion Starter #12
Exactly. Do not run 20w-50 oil in your LT-1. How hot was your engine when this occurred? What weight oil are you currently running?
That's a great question. Shortly after that happened, I got coolant overflow out of the cap. Just replaced the thermostat and fixed that issue. No sign of the oil light yet. It was a hot day when the light flickered.

I'm using Amsoil 0W30. I'm going to check the oil pressure in the next few days to see what's going on.

BTW... to confirm, the car & LT1 has about 292K miles right now.

Lately, I've heard what sounds to be a soft rod knock periodically. For this, would it be best to put in an appropriate additive or go with a higher viscosity oil made for higher mileage engines? I've heard of guys using certain additives with a rod knock and the problem going away...at least for the time-being.
 

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. No sign of the oil light yet. It was a hot day when the light flickered.

I'm using Amsoil 0W30. I'm going to check the oil pressure in the next few days to see what's going on.

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If the light just flickered once at idle but has since been fine don't worry about it.

If it flickers at idle all the time...check oil pressure with a mechanical gauge

using a thicker grade like 10-40 would increase oil pressure.

"Additives" to make engine knocks go away....if they do anything it is just a band aide but can buy some more miles/use of the motor in some cases
 

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When I got Moby, the great white wagon, the top end was so sludged up so much that the oil return holes in the heads were blocked and the car smoked really bad. I pulled the valve covers and cleared that mess out. A few months later, it lost oil pressure, so I dropped the pan, cleaned out all the sludge that was blocking the oil pump pick-up and installed a high volume pump. With 180,000 miles of city/municipal/PARD driving, the engine was not in the best of shape, but with the new pump, I was able to get another year of driving out of the tired old 305 before it started knocking.
 

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Amsoil is good stuff. If you are going to look for another weight, go to a 0w or 5w -40. That should take care of the light blinking. Using 10w will only increase wear on cold startups and do not add additives to the Amsoil. If you are not already doing so, run a 160 stat with reprogrammed fan turn on and off temps. Stock fan setting are way too high and Summer is coming on.
 

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0w40 is good. 0w30 is even better. [Both would be examples of Group 4 'true synthetic' motor oils.]
5w30 & 5w40 are acceptable. [These would either be Group 3 'synthetically processed', or Group 4 'true synthetic' motor oils. Caveat emptor.]

If you don't have any money problems, this would be a great time to buy a new oilpump and a complete set of replacement bearings.
Up to you if you want to wait til after something fails, or install the new oilpump & bearings BEFORE something fails.
 

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0-30wt is good in cold weather .. I used 5-30w or 10-30 wt ...5-30wt does work better in the cold weather like 10F on starting .
since the light did come on use pressure gauge to see whats up...


sludge or pump screen mucked up will do it...


if you do NOT do the oil changes then a quick lube oil change over time will cause oil pump screen muck issues...over the years I have seen this occur on vehicles that did not properly drain all the hot oil out..


look into the oil fill bore and if its mucked up that will do it ..
 

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After going to a 2 day lubrication class and seeing some other information out there about automotive oil...

When running a stock engine you really need to keep your engine as near to what it was engineered to run on.

AMS Oil should NOT be used to try and extend your oil change rate. Unless you use an oil testing place to determine your oil condition you are tempting fate.

Running too thin or too thick of an oil each has their own issues. You want the oil to stay where it is supposed to go but get to your oil pump too.

After seeing a demonstration on the difference between synthetic and standard oil... Well the dirty synthetic oil still flowed DRAMATICALLY better than the clean standard oil. The dirty standard oil barely flowed at all. The changes in viscosity as the oil changes and the sludging up of that oil are only a couple of the reasons to consider. There are protective chemicals in the oil too that will wear out much faster when using the wrong oil for the application and your engine can wear significantly faster if your not changing your oil often enough.

Having said all of that. If your oil light is flickering you SERIOUSLY need to stop driving the vehicle or you will be replacing the engine shortly. You likely need to at a minimum clean the sludge off the oil pickup and off the bottom of the oil pan. You may also need to change the oil pump. If you have the engine torn down enough to be cleaning the oil pickup it would be a bad idea NOT to change the oil pump. And I would start running nothing but synthetic in that engine to allow any of the sludge that may have built up to clean out. May not hurt to do a motor flush to try and flush the crap out before dropping the pan but use clean oil to do so to get best results. I ran motor flush in a stored used motor and the motor spun a bearing within 200 miles after installing the engine. Not sure if the motor flush did it or not but I did run the motor flush for twice the suggested time.

But seriously, if your oil light is flickering, unless you already determined the gauge is bad, your engine is crying for service before it dies.
 

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Rodney,

After going to a 2 day lubrication class and seeing some other information out there about automotive oil...

When running a stock engine you really need to keep your engine as near to what it was engineered to run on.

AMS Oil should NOT be used to try and extend your oil change rate. Unless you use an oil testing place to determine your oil condition you are tempting fate.

Running too thin or too thick of an oil each has their own issues. You want the oil to stay where it is supposed to go but get to your oil pump too.
That all sounds very logical to me.

After seeing a demonstration on the difference between synthetic and standard oil... Well the dirty synthetic oil still flowed DRAMATICALLY better than the clean standard oil. The dirty standard oil barely flowed at all. The changes in viscosity as the oil changes and the sludging up of that oil are only a couple of the reasons to consider. There are protective chemicals in the oil too that will wear out much faster when using the wrong oil for the application and your engine can wear significantly faster if your not changing your oil often enough.

[SNIP]
Okay since I've never been to an oil class, and it sounds like it would be pretty cool, especially if they ad some visual demonstrations (Remember the gear hand-crank, with Lucas oil at the parts stores...).

I have two questions concerning synthetic.

1. What about contaminents in the oil after the typical 5,000-7,000 miles you'd change traditional oil in? To be clear what I'm referring to is that what I had always thought about conventional oil is that it will still get dirty with the by products of combustion.
-Are you supposed to change the oil filter @ 10,000 miles if the interchange directions are 20,000 miles? Then you've got to add an additional quart of oil.

2. Did the instructors have any thoughts, or was the subject adressed, on changing to synthetic oil in a higher mileage vehicle; for example mine @ 180,000?
-Is the old rumor true that a vehicle will start to see oil leaks where you never had them before because of synthetic being slicker than traditional oil, and allowing oil to get by in older worn seals?
-Would one only consider changing if the engine is not curently consuming any oil? What would the criteria be?

Thanks! Those were a few things I've always been concerned about W/synthetic.
 

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If you have leaks, they will be worse when you change to synthetics. Has nothing to do with "slickness" It has to do with molecular sizes and other factors.
BTW, the first number in oil descriptions followed by the W stands for Winter. You want oil to flow freely on startup to reach all parts ASAP. Therefore 0W is the most desirable no matter whether the other choice is 30 or 40. Obviously 5w is the next best. There is no reason at any time to use 10w or 20w oil in our engines. People need to get over the "thicker/thinner" ideas which are outdated in modern close tolerance engines like our LT-1's.
I switched to full synthetic when I bought the car with 120,000, but the car had been a federal car with their excellent maintenance and was never a patrol car.
 
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