Drop in oil pressure

Northstar24

7M FTW
May 19, 2005
56
0
0
Menomonee Falls, WI
All right guys, what would cause a drop in oil pressure when the engine is idling? By drop i mean someplace between the first mark (I beleive that is 20 psi, but its not labeled) and 0 psi. When the car is under load, the pressure hovers between 20 and 40 psi which is a little low according to the owners manual. Its a 91 Turbo with 177K on the original tranny and turbo, if you need any other info let me know. Thanks in advance for the help
 

SupraMario

I think it was the google
Mar 30, 2005
3,467
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The Farm
a little low haha little too low when under pressure it should jump to around 50psi
and when idlings it should be above 20 but below 40.
BHG?
this could be many things.
 
C

cnewingham

Guest
fully warmed up idle can be as low as 4psi. our oil pumps are high volume, low pressure. The stock gauge isnt accurate for shit anyways. At idle my stock gauge will sometimes read at 0 and at 3000rpm it will read under 20.
 

SupraMario

I think it was the google
Mar 30, 2005
3,467
6
38
38
The Farm
cnewingham said:
fully warmed up idle can be as low as 4psi. our oil pumps are high volume, low pressure. The stock gauge isnt accurate for shit anyways. At idle my stock gauge will sometimes read at 0 and at 3000rpm it will read under 20.
really mine seems to work fine, hmm
well in that case i guess to get an aftermarket gauge would be best then.
well thnx for the info cnewingham.
 
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cnewingham

Guest
The turbos heat up the oil pretty good and break down the vescosity rather quickly which is one of the reasons we have turbo timers to allow the oil to cool so it doesnt sludge up through the passages. Most manufactures also suggest using 20w50 if the car has forced induction. I just use castrol cause that is my personal preference.
However if you use synthetic oil then it is totally different than with regular conventional oil. I wont use synthetic in my cars even though it is suppose to be better. I change my oil every 3000 miles anyways.
 

americanjebus

Mr. Evergreen
Mar 30, 2005
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lilazni3uoy said:
is it a bad thing to use full synthetic? cuase i'm using mobile 1 15-50 full syn

no i use 10w40 mobil 1, i dont see why it would be bad, you suggesting half crude,half syn?
 
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cnewingham

Guest
Synthetic is awesome and alot better than conventional but if anythig is loose then you will definetly find out with a leak, also once you go to synthetic you have to stick with it and at $5+ a qt that is a little more than I like to spend. If you use regular oil and change it every 3 thousand miles you wont have anything to worry about anyways. The most important thing for us to do is check the oil level every couple of days cause its not the oil that will cause the rod knock, It is the lack of.
 

Northstar24

7M FTW
May 19, 2005
56
0
0
Menomonee Falls, WI
I am indeed running 5w20, cause thats what Toyota said to run for winter, and in Wisconsin the winters get pretty brutal...so if i swap that out for like 10w40 that should help the problem?
 

SupraMario

I think it was the google
Mar 30, 2005
3,467
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ryans_supra said:
not true, there is no harm switching from synthetic to conventional oils or back.

shwoo had me scared for a moment after i read once u go synth u cant go back.
i just recently went full synth for 1 oil change to see the difference.