I am running 5W 30 Quaker state oil right now. The oil pressure in the car is lower then it used to be. If I used 10W 30 would the oil pressure increase to normal. Right now it runs in the middle or just below on the highway. In the city it runs at just above the redline. It never used to do that. It never used to go below the middle.

Thanks

 

10 psi per 1000 rpm is considered normal, i wouldn't trust the factory gauge too much. if you want to change oil i'd look at 20w-50 for summer

 

Yeah, it does make a difference. When I rebuilt my engine, this guy i knew said he had an oil pump for me that he "modified" for high pressure. Turns out he overmodified the bastard and when i fired it up, it blew the filter off the mount...went through 3 filter before i called his *** up.

He came, switched the oil to 5w30, ground down the lip that the filter rests on, and it worked fine. He said just to use 5w30, so i stuck with it. When summer came along, i had some 10w30 sittin around, decided to use it for an oil change and it ruined my pressure sending unit.

It's cool watching the pressure needle peg when ya start it and it never drops.

But yeah, oil type makes a difference.

Kelly

 

I've never used 5w30, even though thats what they recommend.. I only use the car 6months out of the year.. so I only use Castrol 10w30 .. don't know what the effects would be running anything thicker.

 

what ede said on the 10 psi per 1000 rpm rule.

i'm running a mechanical oil pressure gauge, and i fluctuate between 15-20 psi at idle to as high as 60 when i rev to 4500 or so. i also note here that i am running a standard volume oil pump, as well.

now to just fix that pisser of an oil leak i have an sce 1 piece rubber pan gasket awaiting installation.

ede, mentioning the 20w50 oil, what are the benefits of running such a heavy weight oil? i'm running 10w30 right now, and thinking about switching to a heavy sunthetic once my 305 is broken in. i'm inclined to think that the mobil 1 syn 15w50 we stock at work (it's used in hydro pumps on commercial mowing units) won't work well for me. what other types of synthetic are there on the market? i'm merely used to looking for 10w30 barrel sludge.

 

Well before I used 10W 30. I only run the car in the summer months. The oil change place recomended 5W 30 so I tryed it. The oil pressue was the same until I needed another oil change. When I got the oil changed again I went with the 5W 30 again and the oil pressure stayed lower. I dont know what happend but the car still runs good but I get a little scared when its in the red. I want to know if by changing the oil back to 10W 30 it will bring the oil pressure back up to what it used to be. From what u guys have said it seems like it might boost it back up.... Does anyone else have any other comments or anything on the oil pressure of our cars and what u think I should do.

Thanks again

 

Hmmm.......


Id do another oil change with 5w-30 and see... Its awful wierd how it changed so quickly after a oil change........

 

It might help, but it's hard to say.

A 5w-30 weight oil means that the thinnest it'll get is 5w. The thickest it'll get is 30 weight. But usually the only time it gets as thin as 5w is when it's around 0* outside. So unless you live in Alaska, or on the Eastern Hemisphere, it shouldn't matter. The viscosity of the oil is only based on it's temp. The colder it gets, the 'thinner' it gets, and the hotter it gets, the 'thicker' it gets. (Actually the idea is for it to stay the same consistency in a variety of temps, but you get the idea ).

The only for sure way is to try it. If it don't work, then something else is wrong. Maybe try the 20w-50 that ede suggests. If that works, then go with it. It may just be prolonging the inevitable, but hey, prolonging it is sometimes OK.

AJ

 

where i worked a bunch of techs always reccomended putting 20w-50 in there sports cars for the summer. i havent tryed it yet though.

 

yeah im not sure. Because one day I was driving along and the oil pressure was lower then normal but I thought it was because I needed an oil change. So I got the oil changed and nothing happened. The pressure stayed the same, low. The gauge has always seemed right, I dont know what could have off set it.

I did change the computer chips in the car though. I cant really remeber if the gauge went wrong after that or not. It was around when I changed the chips.

Would changing the chip have any effect on the oil pressure or anything like that. The car runs better with the origional chip in it so im not sure if I want to change back to that crap ADS chip that doesnt seem to do anything except make the car run lean, and lag.

 

5W-30 - Strike One!

Quaker State - Strike Two!

Mineral oil - Strike Three!

I don't even use 5W-oils in -40°F temperatures, but I only keep my cars for 200,000 miles or so, so it doesn't make a lot of difference.

As for the explanation of multigrade viscosity, a 5W- oil is a 5W oil all the time. Its base stock has a viscosity that doesn't change. The oil has fortifiers blended in (polymers) that help the oil maintain viscosity at higher temperatures, so that it acts like an SAE30 oil. These polymers are the first things to burn away when the oil gets hot, weakening the high temperature stability and creating ash and varnish when heated. The larger the span in viscosity range, the greater the amount of added polymers. 5W-30 oil has a viscosity span of 25 basis points, so it has a lot more polymer than a 10W-30 oil with a span of only 20 basis points. With either, after a few thousand miles of operation, the oil left in the crankcase is basically 5W or 10W with no high temperature properties to speak of. If you like running 5W oil in your car in 95°F temperatures, it's your engine. The owner's manual suggests 30W above 40 °F, but do whatever you want. I'm sure the guy at the quikie-lube place is a lubrication engineer, with a doctorite in chemistry, and wouldn't tell you something that wasn't true.

I go by results and sound principle, which is why I use only synthetics in everything from the lawnmowers to the new vehicles. Don't you find it a little strange that a Corvette requires synthetics to maintain the warranty, but the SAME engine in other cars supposedly can run well on mineral oils? Then again, I tend to ignore the SAE ratings and use Kinematic or ISO viscosity ratings instead of the outdated, non-linear SAE system. If you compare on a linear scale you'll see just how bad the 5W oils really are.

 

I just did an oil change. I used Amsoil 0w 30 witha PF35 filter. My oil pressure is fine. I totally beleive in the 10 psi for every 1000 rpms rule, any more is inefficent. You loss power and gas mileage. As to runing the thicker dino oils, why?? It takes horespower to spin parts through that muck, especially on a mild/stock engine with stock type clearances. Unless your engine has some large clearances heavy dino oil is a waste in my opinion. A big hint should be the showroom stock/road racing guys, thye don't run heavy (20w/50) dino juice, synthetics all the way and not as thick.......

 

The oil pressure is fine in the car when I first start it up and drive it. The gauge is where it should be. The problem is that the oil pressure drops alot once then engine is warmed up or hot from inner city driving. The oil pressure never used to drop that much when it was hot. I dont know if it could be because of somthing else.

Anyone got any ideas on why the oil pressure would be normal when the engine is cool, but when the engine gets hot from city driving the pressure drops. What goin on.

I am thinking about getting an oil cooler to solve that problem. Do u think that would help keep the oil pressure up because the oil is cooler.

Thanks

 

When I first got my car I did an oil change on the weekend and used 5w 30 Mobil synthetic,when I was on my way to work Monday morning sitting in traffic in the middle of summer I looked down at the gauge and freaked.It was as low as it could go,I pulled over thinking that I didnt tighten the filter or left the friggin bolt out and had no oil.When I got home that night I dumped out $30 worth of Mobil 1 and put 20w 50 in it (Mobil 1),oil pressure back to normal!

 

Yeah... Im thinking that its the 5W 30 oil in the car that is making the oil pressure gauge messed up. I am going to change the oil to 10W 30 tonight. Ill let u know what happens.

Thanks for all the help

 

Vader covered most of the pertinent points, however the reason 5-30 wt. oils became the factory fill for almost any car made in the last 10 years or so is because it helps manufacturers increase maybe only ever so slightly fuel economy. Another reason told to me by a Chrysler rep was that with the advent of small overhead cam engines fast oil delivery to the upper end was critical. The cam material used is softer than it used to be so having oil to lubricate as fast as is possible prolongs cam life. A thinner oil also helps any engine crank easier. I would never run dino 5-30, and here's why. Our 98 Blazer after breakin was guzzling oil like crazy. It was not coming out the pipe, just cooking off. I changed it over to Mobil 1 and it goes 6k between oil changes and only consumes about a half qt. Not enough to even add any. GM states that acceptable oil consumption using a 5-30 oil is one quart/4k miles. With synthetic, any of our GM cars require no oil between oil changes. In most applications 5-30 wt oils will perform fine, Mobile 1 5-30 is the vette fill as Vader stated. I believe 91 was the first year they did that and I was told by a Mobile engineer that they went with synthetic because they wanted to eliminate the oil cooler to save weight. I run 5-30 in everything but it is only synthetic. I feel I get the benefits of a lighter grade without having to worry about excessive cooking off of the base stock. Look at the flash points for dino vs. synthetic in the oil company inspection data they all provide and you will see for yourself. You go to any dealership of any brand and the mechanics are about evenly split on what viscosity to use. Same thing with Dexcool, half the guy's at the dealer we use drained out the Dexcool and put in conventional coolant. They claim cases of cars with Dexcool coming in and it basically turned to mud. Been running it since it first came out, never had a problem. My camaro in 95 degree weather with the AC on sits at about a little less than 30lb. oil pressure using 5-30.