Low Cold Engine Oil Pressure

burnthefurniture · November 28, 2013

Hey guys,

Hopefully someone can help me shed some light on this. It may be an issue, it may not be, but I would like to get some input.

I have a 2006 Silverado 1500, 5.3 liter. Just over 104,000 miles on the clock. I run Royal Purple Oil, K and N filters. I change the filter and top off every 3,000 and do a full engine oil change every 10,000 miles. Lately, on cold mornings I have noticed my cold oil pressure doesn't seem go as high on initial startup as some other trucks. Similar year model trucks running dino oil get about 50-55 lbs cold oil pressure on startup and stay that way for a while before stabilizing.

We have been having colder mornings (30-50 degrees here in good ole Louisiana). My truck lately has been getting about 40 lbs on cold startup lately, and quickly leveling out to 35 lbs cold idle where it stays rock solid. When driving cold, I may get up to 40-42 lbs, but typically not higher. Once the oil/engine warms up, I see it fluctuate from 35 lbs hot idle to 50 lbs hot running. I get 60-75 WOT.

I can't imagine (though it is possible) that I have a sludged up motor, but are there any other reasons why I might notice this? I'm all ears, and it may not be a problem but I want to make sure I'm not having any issues popping up. I know it is within the year model that can have the castech head issue, and I have a 706 casting, but to the best of my knowledge, I've never lost any coolant. I've never added any and it stays constant on the tank, though slightly lower on colder mornings.

Thanks!

demech23 · November 28, 2013

I understand that your that the oil is expensive, so I see you reasoning for your 3000-10000 oil change interval procedures. However from my past experiences for working at a dealership, the longer oil change intervals will not help you in the long run. Oil trap contaminates, and a single oil molecule can pass through your motor up to seven times before going through your oil filter. But on the flip side, the 02 Avalanche that has a 5.3 which is still in the family had Speedee mobil1 oil changes every 10-12k from new until it had roughly 270k on the clock two years ago, and it is still running strong. If your just going to throw parts at it. The oil pressure sender would be a start, and an new oil pump would be a more of a worst case scenario from there. Good luck.

Gurrzt · November 28, 2013

I understand that your that the oil is expensive, so I see you reasoning for your 3000-10000 oil change interval procedures. However from my past experiences for working at a dealership, the longer oil change intervals will not help you in the long run. Oil trap contaminates, and a single oil molecule can pass through your motor up to seven times before going through your oil filter. But on the flip side, the 02 Avalanche that has a 5.3 which is still in the family had Speedee mobil1 oil changes every 10-12k from new until it had roughly 270k on the clock two years ago, and it is still running strong. If your just going to throw parts at it. The oil pressure sender would be a start, and an new oil pump would be a more of a worst case scenario from there. Good luck.

I respectfully disagree with this statement, I have been using pure synthetic oil in Sara (2001 Z28, 37k original miles) changing the oil every 2 years (adding when necessary), and have no ill effects from doing this.

I owned a 2004 Chevrolet Tahoe (4.8L) with 117k original miles and used high grade synthetic oil changed every 10k, and had no ill effects from doing this.

The dealer uses a synthetic blend oil, that I would not use in my lawn mower.

JMHO

jrrod2004 · November 28, 2013

Hey guys,

Hopefully someone can help me shed some light on this. It may be an issue, it may not be, but I would like to get some input.

I have a 2006 Silverado 1500, 5.3 liter. Just over 104,000 miles on the clock. I run Royal Purple Oil, K and N filters. I change the filter and top off every 3,000 and do a full engine oil change every 10,000 miles. Lately, on cold mornings I have noticed my cold oil pressure doesn't seem go as high on initial startup as some other trucks. Similar year model trucks running dino oil get about 50-55 lbs cold oil pressure on startup and stay that way for a while before stabilizing.

We have been having colder mornings (30-50 degrees here in good ole Louisiana). My truck lately has been getting about 40 lbs on cold startup lately, and quickly leveling out to 35 lbs cold idle where it stays rock solid. When driving cold, I may get up to 40-42 lbs, but typically not higher. Once the oil/engine warms up, I see it fluctuate from 35 lbs hot idle to 50 lbs hot running. I get 60-75 WOT.

I can't imagine (though it is possible) that I have a sludged up motor, but are there any other reasons why I might notice this? I'm all ears, and it may not be a problem but I want to make sure I'm not having any issues popping up. I know it is within the year model that can have the castech head issue, and I have a 706 casting, but to the best of my knowledge, I've never lost any coolant. I've never added any and it stays constant on the tank, though slightly lower on colder mornings.

Thanks!

Truthfully, I think it is the colder weather contracting some seals and the oil itself thus making this issue a bit more noticeable. I have virtually the same truck as you and am in Austin with the same results. You didnt mention which oil weight you were running but I figure either 5W-30 or 10W-30.

As a simple, free test, (if you have remote start), get upwind of your tailpipe, start it up and see what happens over 5-10 minutes. Also notice the smell and see if any sweet smell comes out. If there is no smell (besides exhaust) and no burning of any kind, I would say that you are fine.

demech23 · November 28, 2013

I respectfully disagree with this statement, I have been using pure synthetic oil in Sara (2001 Z28, 37k original miles) changing the oil every 2 years (adding when necessary), and have no ill effects from doing this.

I owned a 2004 Chevrolet Tahoe (4.8L) with 117k original miles and used high grade synthetic oil changed every 10k, and had no ill effects from doing this.

The dealer uses a synthetic blend oil, that I would not use in my lawn mower.

JMHO

For this time I guess we'll have to agree on that we disagree. There are reason's why GM has current Service Bulletin updates for shortening their vehilces' DIC oil change interval. I wasn't trying to bash anyone who goes extended oil changes, but temperate and driving habits greatly affect when you should change your oil. Once again look at our 02 Avalanche that has a lot of miles on that 5.3l, and had extended oil change intervals.

GM oil is good oil, it has to be in order to back up warranty for things like extended oil changes. However, some dealers tend to not use GM oil programs because it cost too much, and instead use an economic oil from an outside vendor that meets the GM spec. One of the reasons other than keeping low running costs, GM sends out mailer coupons for oil change specials and what ever. Now if the oil change is at a price that is much lower than the total cost of GM oil and filter before any labor the dealer has to accept the use of the coupon the customer presents and find ways not to take a major lost.

Back to Burnthefurniture, at least you have been using a synthetic oil. You'd be amazed to see how some of the newer pickups' oil pressure gauges moves due to temp, and operating at WOT>cruising>stopped in drive>parked. Now you'd know if you had a sludge up motor; they just don't run well, the motor would shake and makes all sorts of noise most of the time, and during oil and filter changes you'd see the sludge. Plus synthetic oil doesn't break down like conventional, its finer molecules so they tend to actually clean the motor and remove sludge build ups. What ever you do, do not do an "Engine Flush" of any sorts. I hope that this helps.

kstruckcountry · November 28, 2013

You have enough pressure IMO. My 2006 runs near that, and it's always ran great. It sees colder temps than yours too.

If you're worried about it, send in an oil analysis. They can tell you exactly what's in your oil.

txab · November 28, 2013

If you're concerned, check pressure with a mechanical gauge.

Red Clay · November 28, 2013

My 05 stays starts at around 35-40 gets up to about 60 on the interstate here in Colorado. But I gotta ask are y'all high? Oil changes every two years? I think 10000 is pushing it. I run amsoil in my bike and change every 5000, I run castrol full synthetic in both my trucks with Fran tough guards and change every 5000.

K&n oil filters are crap there have studies to show they don't catch as many contaminants as other brands to include factory ones.

Your oil pressure is fine but if you think you have lost some, check for leaks around the heads and the pan. Also do a compression test this will let you see if your rings and/or cylinders are wore and could be burning a slight amount if oil.

burnthefurniture · November 29, 2013

Thanks for the replies. A couple more details I didn't mention the other day. In addition to the RP and K and N filter, I run a filter mag magnet in addition to the little magnet that is stock on the drain plug. The motor is and always has been absolutely dead silent. Not once, even in the coldest temperatures that Louisiana can muster have I ever had a tick or lifter tap on startup. The truck runs great, and very strong, so I wanted to post mainly for the sake of being proactive.

I understand that your that the oil is expensive, so I see you reasoning for your 3000-10000 oil change interval procedures. However from my past experiences for working at a dealership, the longer oil change intervals will not help you in the long run. Oil trap contaminates, and a single oil molecule can pass through your motor up to seven times before going through your oil filter. But on the flip side, the 02 Avalanche that has a 5.3 which is still in the family had Speedee mobil1 oil changes every 10-12k from new until it had roughly 270k on the clock two years ago, and it is still running strong. If your just going to throw parts at it. The oil pressure sender would be a start, and an new oil pump would be a more of a worst case scenario from there. Good luck.

The oil is expensive, yes, but so is a new motor. The oil price or filter price was never my motivation behind the change interval. I bought 3 cases of 5w30 RP a few years ago and change according to my interval, which is roughly based on oil analysis. A close friend with identical truck and very similar driving situations who uses the same oil, filter, magnet combination has tested his oil after every change for over 100,000 miles and every time he sent it in, they told him he could run it longer...up to over 25,000 miles. Now, that seems ridiculous to me and while it is not my truck that testing was done on, I would never trust running the same oil for that long, just from a standpoint of contaminants as mentioned. However with mobil 1 and some others touting extended changes up to 15,000 on a single OCI and single oil filter, I feel that my interval was a pretty good medium between all of the above. Nothing at all scientific about it, so don't flame me. Just the motor runs great, very strong, and dead silent.

Truthfully, I think it is the colder weather contracting some seals and the oil itself thus making this issue a bit more noticeable. I have virtually the same truck as you and am in Austin with the same results. You didnt mention which oil weight you were running but I figure either 5W-30 or 10W-30.

As a simple, free test, (if you have remote start), get upwind of your tailpipe, start it up and see what happens over 5-10 minutes. Also notice the smell and see if any sweet smell comes out. If there is no smell (besides exhaust) and no burning of any kind, I would say that you are fine.

Austin and BR have very similar climates, so I am appreciative to hear that there are others with similar experiences. I run a 5w-30.

For this time I guess we'll have to agree on that we disagree. There are reason's why GM has current Service Bulletin updates for shortening their vehilces' DIC oil change interval. I wasn't trying to bash anyone who goes extended oil changes, but temperate and driving habits greatly affect when you should change your oil. Once again look at our 02 Avalanche that has a lot of miles on that 5.3l, and had extended oil change intervals.

GM oil is good oil, it has to be in order to back up warranty for things like extended oil changes. However, some dealers tend to not use GM oil programs because it cost too much, and instead use an economic oil from an outside vendor that meets the GM spec. One of the reasons other than keeping low running costs, GM sends out mailer coupons for oil change specials and what ever. Now if the oil change is at a price that is much lower than the total cost of GM oil and filter before any labor the dealer has to accept the use of the coupon the customer presents and find ways not to take a major lost.

Back to Burnthefurniture, at least you have been using a synthetic oil. You'd be amazed to see how some of the newer pickups' oil pressure gauges moves due to temp, and operating at WOT>cruising>stopped in drive>parked. Now you'd know if you had a sludge up motor; they just don't run well, the motor would shake and makes all sorts of noise most of the time, and during oil and filter changes you'd see the sludge. Plus synthetic oil doesn't break down like conventional, its finer molecules so they tend to actually clean the motor and remove sludge build ups. What ever you do, do not do an "Engine Flush" of any sorts. I hope that this helps.

I've run synthetic oil ever since about 36,000 miles. Before that, I was getting oil changes at the dealership based on the OCI while they were free. It was really just too time consuming to wait 2 hours for an oil change for free when I can do it in 20 minutes at home. Since then I have run synthetic. For what it is worth, I changed my oil yesterday, just to test a few things. I drove about 15 miles and changed it as soon as I got home, to flush out any contaminates and sludge while still in suspension. My RP stash had run out on the last OCI so I bought Mobil 1, just to change things up. While the drain plug was out, I had a piece of wire which I stuck into the bottom of the pan to see what I could "feel" in the way of sludge or contaminates, if there were any. This was not a scientific test at all, and it was based on my assumption that such would fall to the sump of the pan. The pan was absolutely clean, no resistance in wiggling side to side, and nothing but clear oil came out. I also removed the oil filler neck and looked into the top end to see what I could see with a flash light. It, too was absolutely spotless, nothing but a slight oil discoloration on the metal as you would see on any motor.

You have enough pressure IMO. My 2006 runs near that, and it's always ran great. It sees colder temps than yours too.

If you're worried about it, send in an oil analysis. They can tell you exactly what's in your oil.

I mentioned above that I changed to Mobil1 with my change yesterday just for grins and giggles. Across the board, hot or cold, I am seeing about 5 psi higher in every regard. I am considering this could be a difference in flow characteristics of the two oils. RP people claim Mobil 1 is not on the same level of synthetics as Amsoil, RP, Redline, etc., but nevertheless, its a great oil and just a possible different formula could cause this result.

My 05 stays starts at around 35-40 gets up to about 60 on the interstate here in Colorado. But I gotta ask are y'all high? Oil changes every two years? I think 10000 is pushing it. I run amsoil in my bike and change every 5000, I run castrol full synthetic in both my trucks with Fran tough guards and change every 5000.

K&n oil filters are crap there have studies to show they don't catch as many contaminants as other brands to include factory ones.

Your oil pressure is fine but if you think you have lost some, check for leaks around the heads and the pan. Also do a compression test this will let you see if your rings and/or cylinders are wore and could be burning a slight amount if oil.

Based on my previous responses, I am much less worried about the pressure as I was previously, however I would be interested to see what your source about the k and n filters is. I am not looking to contest you, I have always wanted to have the best filter for filtration and flow and if its not K and N, would love to see a side by side comparison of what is best.

Red Clay · November 29, 2013

Ill see what I can dig up for ya. However, I learned this thru a buddy that sent his oil in for analysis from his CBR 1000. He tried many brands of filters each for one month all using amsoil. He said the k&n oil filter was the worst outta the five he tested. So just take what I said for what you want. I just know that I changed the filter the next day on my old vw gti and come the next oil change my catch can held a lighter color inside it.

That filter mag is probably one of the best ideas I have heard in a while so props for that.