is 10w30 thicker than 5w30 when warm?
11-03-2008, 11:37 PM
#16
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You don't need anything thicker. You used two different oil sending units and have two different results - obviously it's not the oil.
It's either a bad sending unit, bad gauge, debris in the oil sending unit and/or fittings, something internal or a combination of any of these. Thicker oil will not solve your problem (it might mask it, though)
It's either a bad sending unit, bad gauge, debris in the oil sending unit and/or fittings, something internal or a combination of any of these. Thicker oil will not solve your problem (it might mask it, though)
it seems to have more to do with the ambient air temp than the actual engine temp, ie say its @ 210. @ 210 with an air temp of 70 it won't throw a CG light but will sit around 10psi at idle, but if the air temp is around 85 and the engine temp is around the same temp, the CG light will come on if the car sits at idle for more than a minute or so
you know, i wouldn't be suprised if it was in fact a bad OSU and that the one that is in there now was a cheapie (although IIRC i paid $45 bux for it) and is not reading right, and the $20 one i got from autozone was even worse (since it wouldnt hold ANY oil pressure at idle once the car warmed up)... i wishi had a known good one to throw on there. i suppose i could do the mechanical gauge thing although it'd be hard to see while sitting in gear
Last edited by 1995blackttopta; 11-03-2008 at 11:43 PM.
11-04-2008, 12:50 PM
#17
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The only way you are going to verify that your pressure is ok is but getting a mechanical gauge and hooking it up. So, that is your first assignment. Do that and come back with the results and then we can go from there. Until you verify your pressure with a mechanical gauge, we can make all the wildest accusations in the world without really fixing the problem.
11-04-2008, 03:42 PM
#18
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i took the car and had the oil changed, they did not hook it up to a gauge but i did up the oil to 10w30 (they didn't have 10w40) i did some tests while at home (video being uploaded currently) after the oil change and i "think" i got to the point where with the 5w30 the CG light would have come on since the engine temp was @ 220 (warmest it got cause the fans came on as they are supposed to) and snapped this pic of the gauge
one thing i notice is under hard braking it does NOT go right down like that, it only lowers like that after its sat for a few mins (FWIW this pic was actually taken while the car was in reverse)
here is the vid i was referring to. at the end of the vid you can see the car cooling down a bit because of the fans
http://www.youtube.com/watch?v=Myfc5...?t=1668&page=2
one thing i notice is under hard braking it does NOT go right down like that, it only lowers like that after its sat for a few mins (FWIW this pic was actually taken while the car was in reverse)
here is the vid i was referring to. at the end of the vid you can see the car cooling down a bit because of the fans
http://www.youtube.com/watch?v=Myfc5...?t=1668&page=2
Last edited by 1995blackttopta; 11-04-2008 at 04:24 PM.
11-05-2008, 03:30 PM
#19
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Like was said earlier, thicker oil won't fix the problem, only mask it i.e. if you have a bad bearing its not going to make things better.
This still does not tell if your getting good pressure or if it is the sensor.
This still does not tell if your getting good pressure or if it is the sensor.
11-05-2008, 04:59 PM
#20
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Until you get a mechanical gauge on it you wont be able to be sure.
Now barring all talk of a worn engine (obviously this would be the culprit if not the sending unit). If you dont want the oil pressure to drop so low the answer really isnt to increase the viscocity of it the cst values of 40w are really not going to do you much good the difference from 30-40w isnt the 25% that is implied from the numbers. It is only a fraction of that depending on the particular oil being uses and at what temps.
Your best option for increasing oil pressure is to speed the engine idle up for 1. Its just really not the best oiling wise to idle at 550rpm the way stock a4 cars do. The next thing you can do is to put in a cooler t-stat and set the fans to come on at a cooler temp.
The viscocity of an oil is related to its temp, as you approach very high oil temps like 300*f many oils become VERY similar in terms of cst values, even gear oil becomes like 30w. Ideally you want a very thin oil at cold temps so it flows and lubricates everything right away and an oil that doesnt become too thin at operating temps.
As an experiment some of you should try sitting a jar of your oil outside over night during winter, then in the morning turn the jar over and try to pour it out. That is what your engine is trying to cram through .002-.003" gaps. Some out there are running around with 20-50 in thier oil pan in the winter
. That crap will look like a cows tongue if you try to pour it out after its sat all night at 25. To which many will say but i have loads of pressure in the morning. Yes and you also have a bypass in your oil system and oil that takes the bypass in the pump doesnt lube anything. Pressure != lubrication.
Having said all that your oil pressure at idle is really not terribly critical. There is almost no load at idle. If there is even 10psi at idle you will be ok as long as it pops up right away when rpms increase even a little.
As for some of the stuff said in this thread about oil and pressure.... wow.
Now barring all talk of a worn engine (obviously this would be the culprit if not the sending unit). If you dont want the oil pressure to drop so low the answer really isnt to increase the viscocity of it the cst values of 40w are really not going to do you much good the difference from 30-40w isnt the 25% that is implied from the numbers. It is only a fraction of that depending on the particular oil being uses and at what temps.
Your best option for increasing oil pressure is to speed the engine idle up for 1. Its just really not the best oiling wise to idle at 550rpm the way stock a4 cars do. The next thing you can do is to put in a cooler t-stat and set the fans to come on at a cooler temp.
The viscocity of an oil is related to its temp, as you approach very high oil temps like 300*f many oils become VERY similar in terms of cst values, even gear oil becomes like 30w. Ideally you want a very thin oil at cold temps so it flows and lubricates everything right away and an oil that doesnt become too thin at operating temps.
As an experiment some of you should try sitting a jar of your oil outside over night during winter, then in the morning turn the jar over and try to pour it out. That is what your engine is trying to cram through .002-.003" gaps. Some out there are running around with 20-50 in thier oil pan in the winter
. That crap will look like a cows tongue if you try to pour it out after its sat all night at 25. To which many will say but i have loads of pressure in the morning. Yes and you also have a bypass in your oil system and oil that takes the bypass in the pump doesnt lube anything. Pressure != lubrication.Having said all that your oil pressure at idle is really not terribly critical. There is almost no load at idle. If there is even 10psi at idle you will be ok as long as it pops up right away when rpms increase even a little.
As for some of the stuff said in this thread about oil and pressure.... wow.
11-05-2008, 05:56 PM
#21
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Join Date: Feb 2008
Location: Hicksville, OH
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My Camaro's oil pressure went to looking like that one night after I was romping on it going down a curvy road. I put on a mechanical gauge and it eased my thoughts until I found metal shavings in my oil at the last oil change. I threw in some 10w40 and parked it for the winter. In the spring, the motor is getting gone through.
11-05-2008, 08:53 PM
#22
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Join Date: Aug 2006
Location: Encinal, Tx
Posts: 343
Since there has been no mechanical gauge put on the car to see if its the oil pressure sending unit or the motor i'd b taking a wild guess that it may be ur oil pump. I run 5w30 all year round and I live in south texas where it rarely gets below 40 degres.
BTW My camaro's have 170k miles on them with no rebuilds.
BTW My camaro's have 170k miles on them with no rebuilds.
11-06-2008, 11:52 PM
#23
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Until you get a mechanical gauge on it you wont be able to be sure.
Now barring all talk of a worn engine (obviously this would be the culprit if not the sending unit). If you dont want the oil pressure to drop so low the answer really isnt to increase the viscocity of it the cst values of 40w are really not going to do you much good the difference from 30-40w isnt the 25% that is implied from the numbers. It is only a fraction of that depending on the particular oil being uses and at what temps.
Your best option for increasing oil pressure is to speed the engine idle up for 1. Its just really not the best oiling wise to idle at 550rpm the way stock a4 cars do. The next thing you can do is to put in a cooler t-stat and set the fans to come on at a cooler temp.
The viscocity of an oil is related to its temp, as you approach very high oil temps like 300*f many oils become VERY similar in terms of cst values, even gear oil becomes like 30w. Ideally you want a very thin oil at cold temps so it flows and lubricates everything right away and an oil that doesnt become too thin at operating temps.
As an experiment some of you should try sitting a jar of your oil outside over night during winter, then in the morning turn the jar over and try to pour it out. That is what your engine is trying to cram through .002-.003" gaps. Some out there are running around with 20-50 in thier oil pan in the winter. That crap will look like a cows tongue if you try to pour it out after its sat all night at 25. To which many will say but i have loads of pressure in the morning. Yes and you also have a bypass in your oil system and oil that takes the bypass in the pump doesnt lube anything. Pressure != lubrication.
Having said all that your oil pressure at idle is really not terribly critical. There is almost no load at idle. If there is even 10psi at idle you will be ok as long as it pops up right away when rpms increase even a little.
As for some of the stuff said in this thread about oil and pressure.... wow.
Now barring all talk of a worn engine (obviously this would be the culprit if not the sending unit). If you dont want the oil pressure to drop so low the answer really isnt to increase the viscocity of it the cst values of 40w are really not going to do you much good the difference from 30-40w isnt the 25% that is implied from the numbers. It is only a fraction of that depending on the particular oil being uses and at what temps.
Your best option for increasing oil pressure is to speed the engine idle up for 1. Its just really not the best oiling wise to idle at 550rpm the way stock a4 cars do. The next thing you can do is to put in a cooler t-stat and set the fans to come on at a cooler temp.
The viscocity of an oil is related to its temp, as you approach very high oil temps like 300*f many oils become VERY similar in terms of cst values, even gear oil becomes like 30w. Ideally you want a very thin oil at cold temps so it flows and lubricates everything right away and an oil that doesnt become too thin at operating temps.
As an experiment some of you should try sitting a jar of your oil outside over night during winter, then in the morning turn the jar over and try to pour it out. That is what your engine is trying to cram through .002-.003" gaps. Some out there are running around with 20-50 in thier oil pan in the winter
. That crap will look like a cows tongue if you try to pour it out after its sat all night at 25. To which many will say but i have loads of pressure in the morning. Yes and you also have a bypass in your oil system and oil that takes the bypass in the pump doesnt lube anything. Pressure != lubrication.Having said all that your oil pressure at idle is really not terribly critical. There is almost no load at idle. If there is even 10psi at idle you will be ok as long as it pops up right away when rpms increase even a little.
As for some of the stuff said in this thread about oil and pressure.... wow.
based on how the car drives and what the gauge reads when cold and when being driven i still think it might be a bad gauge. i should probably try to see if i can find someone with a known good gauge and test it since the gauge i put in to test it last time showed worse pressure than i had already.. that was a cheapie $20 autozone gauge. I guess i'll have to check it in the spring or something. yesterday i put the car away for the winter.
living up north sucks. my car is rust free and i plan on keeping it that way
Last edited by 1995blackttopta; 11-06-2008 at 11:57 PM.
11-07-2008, 09:45 AM
#24
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Join Date: Aug 2006
Location: Atlanta
Posts: 13
you know that leads me back to where this all started. When the trans was rebuilt last november the car lost all oil pressure due to a broken OSU. they put in a new one and all seemed ok until the temp warmed up above 80 that next summer (truthfully i didnt drive it at all through the winter) and when the temps were above 80 the CG light would come on sometimes going into reverse or sitting at a light.. any cooler than 80 or so and it would be fine.
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