shtnfrds

iTrader: (1)

hey all, i just bought a z28 from a board member here. going to do an oil change this eve and wanted to know what thoughts were on using 20-50 wight oil?

At idle it's oil pressure is just barley over 20 cruising its at about 30-35 and if i get on it hard its 45-50. no more than that.

will also be replacing the sending unit as i have heard they can have false readings and show low pressure. which brings me to my next question, is it possible to change it without pulling the intake?

TIA.

ghardester

Don't put much faith in that gauge. In most years it's just an indicator rather than an actual measure. Where you are at and what temperatures and driving conditions would be good info.

NC01TA

Why 20-50?? Is the engine modded? You could be asking for trouble otherwise. You better get an owner's manual if the car didn't come with one. Follow GM recommendations unless you know what you are doing.

shtnfrds

iTrader: (1)

im in ks, temp of engine i assume you mean, and it hold firm at a tick under 210, if you mean outside temp its about 85 or 90. but it has the same as last night when it was 70 out. It's not a race car, it's just a z28 with LT ORY and duals. just like a ton of other z's out there. it's the One that was for sale on this forum with 164000 miles. and yes i know that crazy high miles but just like any other motor that is taken care of. it's still strong. i was actually thinking i might swap oil pumps so it's gonna come down to the answer to this thread.


20-50 because it could help increase the oil pressure? it's a thicker oil right? or am i thinking in the wrong direction and i should go thinner?internally modded no, but would that make a difference? would the 20-50 cause a problem? if so, how and what kind of problems?

9000th01ss

iTrader: (10)

You might want to consider adding seafoam to the oil to dissolve/emulsify some gunk build up.

Since you don't know whats in it now, change it with 10w30. If it starts knocking you have a problem. You can change the sending unit from up top with the intake on.

I used to put 20w50 and a quart of STP oil treatment in my dually to keep it from knocking. It later spun a rod bearing and threw two rods out of the pan.
Hopefully no one put that mix in your car.

NC01TA

C'mon my friend. You are going to hurt your car over time. The owner's manual (page 6-14 in my '01 version) states "DO NOT USE SAE 20W-50 or ANY OTHER GRADE OIL NOT RECOMMENDED". Use 5W-30 or 10W-30. Yes, you can harm your engine. Stop listening to friends who are 'experts'. I think GM has a reason for warning owners.

Rhedalert

iTrader: (21)

Go with one of the better quality 30-weights like the German Castrol 0W30 or Pennzoil Platinum 5W30. They are on the "heavier" side of the 30 weight measurement and hold up for a long time. Use it and be done with it.

WhiteFormula98

iTrader: (10)

0w-40 car runs better, and engine sounds better

LS1Formulation

iTrader: (13)

I swapped oil pumps in my car and had similar oil pressure issues. I found that I used the wrong O-ring on the oil pump pickup. Pulled it back apart, put the thicker O-ring in and my oil pressure jumped up to 40 PSI hot at idle and 60+ at anything over idle. My engine also has 150K on it. If the pump was changed previously, this could be the problem.

shtnfrds

iTrader: (1)

not sure if it has been, but i put 10-30 in it and a delco filter, hot idle it sits just a sntch hair low of 40 and cruising at 1800rpm its 45-50 area. so i'm not gonna f with the sending unit, looks to be a pita anyways, pump i will probably do. whats a good quality pump you guys would recomend? I can get an ls6 pump and lifters for 200+shipping. good deal?

slowjoe99

iTrader: (7)

EXACTLY! Get the "revised" version of the oil pump pick up tube o ring at the dealership for 4-5 bucks and put that in. There is a good chance of that helping and you can do it yourself but will be kinda tricky!

chaman

iTrader: (5)

Get a KN oil filter and you will see the oil pressure go up to healthier levels. This same topic has been beaten to death here. I use a combination of Mobil 1 10/30 with one 50 Mobil 1 quart. Works really good as was recommended by a respectful long time member here....some time ago. If unsure just follow the manual recommendations. Some of you should know that at times those manufacturer recommendations are more influenced by EMISSIONS rather than what is really good for your engine. Thinner oil raises engine temps thus eliminating emissions more effectively....but...is really that good?