Lazlo

My LT1 has about 180k on the clock now and it's starting to lose oil pressure. It's fine except for at idle, which is not great but ok. The problem is when it gets hot(not overheating just higher end of normal range) and I stop at a light or in traffic the guage drops real low, sometimes enough to set of the check guages light. I plan on rebuilding the engine but I need it to hold on for a few months so I can save up some more cash. Either that or maybe rebuild the bottom end now and do my heads/cam later. So what I'm wondering is should I change the weight of oil I'm using(if so to what), rebuild it now, or just let it go and hope it stays together?

396D1SS

iTrader: (21)

what oil are you running? define low psi? 2,3,4?

Lazlo

I'm running mobile1 5w30 always have. What does that number mean, 5 hot/30 cold? Should I try like a 20w30(assuming they have something like that) or just go up to 10w30? As far as the exact psi I'm not sure, just going off the stock guage. After it's warm it hovers just above the red mark and will start dropping into the red with the check guages light coming on as it gets hotter.

Formula350

iTrader: (3)

I think a picture would help us as far as pressure goes. LT1s idle with very low pressure anyways. I know mine does.

You COULD run 20w30, it's considered more to be a "race" weight though. As for the numbers, yea hot/cold is pretty easy way to say it. I'd try 10w or even 15w before going straight to 20.

infinitebird

iTrader: (11)

It helps if you go with a thicker weight like 0w40 or 5w40. I believe there were some tests that indicated this was a better choice for the lt1 than the 5w30 recommended.

Formula350

iTrader: (3)

When we first got bottles of 0w20 and 0w30 into my work, I shook them and it sounded almost like water. How is 0w40 any better? Larger the number is the thicker the weight. Otherwise our gear lube would be pretty much literally water.

infinitebird

iTrader: (11)

You just answered your own question. It would be better because 40 is thicker than 30, which is thicker than 20 etc.

Running a thicker oil can sometimes help you increase oil pressure. Of course this is only a temporary solution. It will still need a rebuild eventually.

Formula350

iTrader: (3)

Between our posts, I read up on oil weights, and all along, I was a bit confused as well as given a bit of misinformation. I always thought the second digit was the "room temp" weight, and the first was the running temp weight. So 5w30 was better in the winter, so you wanted your motor the crank over better. I learned all this when I didn't know beans about cars, and so some of the things I learned just stuck with me! What I still don't understand is why the 0w30 was water like and the 5 or 10w30s were thicker when shaken. I mean, it was very apparent when doing that. According to what I read, the 0w thru 15w-30 oils should all be the same at room temp.

Gah, I hate the technicals behind Oil

V8sounds

iTrader: (1)

I'm interested to know what a "normal" or safe oil pressure is both at startup and once warmed up.

infinitebird

iTrader: (11)

None of the numbers are "room temp".

The first number is the cold viscosity, measured at 0 deg. The second number is "running temp" viscosity measured at 210 deg. Room temp is in the middle of these but since the first number is the weight closer to room temp (ex. 70 - 0 < 210 - 70) a 5w30 will be thicker at room temp than a 0w30.