PSU 98

iTrader: (4)

Read the thread. There is a difference in "cold air" and a "cold engine".

stefan256

iTrader: (1)

Well today I got stuck in traffic for about 45 minutes and finally reached around 210 then dropped to about 170 within 20-30 seconds it seemed, but when it did get hot my oil pressure dropped pretty bad down to around 20 psi but after a little rev while sitting there jumped to around 40. Anything to be concerned about?

PSU 98

iTrader: (4)

I didn't know '98 temp gauges were more accurate, if so then 170-210 is nothing to really worry about. My bet is still that there's a lower t-stat in there. On my 2002, the gauge points straight north to 210 and stays there.

A general rule for adequate oil pressure is 10 psi for every 1000 RPMs. My stock pump used to see 40 psi at idle though, so maybe it's another year-specific thing?

stefan256

iTrader: (1)

well it was just weird while in traffic i was putting it in park and drive was sitting for 5-10 minutes at a time in park it would go back up to around 35 psi in drive sitting at 20-25 but when i would accelerate around 1200 rpm i would be seeing close to 45 psi so I thinking I'm safe

edit: later today started it up and checked it and was idling around 35-45 psi stayed there except with some moderate throttle was getting around 60psi

hammertime

iTrader: (1)

As long as the engine is getting hot enough to go in to closed loop, you should be fine. Are you reading the temp from the stock gauge? They aren't always consistant or accurate, so if you are blowing out plenty of hot air when it is up to temp, it may be nothing at all.

Raising the operating temperature has more to do with emissions and oil life than "complete combustion". Oil temp generally parallels the water temp, so higher water temps help to boil off condensation and prevent sludge.

I'd try checking the water temp with a different gauge to see how close your gauge is, then check to see what temp the thermo is. Just putting a hotter thermostat in without changing the fan on/off temps is not ideal, so see if you can get someone to check your PCM out as well.

I'm betting on gauge. If you read the Difference Between the Years sticky, you'll see that 1998 has an actual temp gauge, while 1999+ cars had a redesigned unit that basically reads in the middle of the gauge as long as it is in a certain range. This was to reduce complaints of cold/hot running cars from cheap gauge & sending units that read off a fair amount.

hammertime

iTrader: (1)

DOH - Should have read the whole thread before posting. Now I see much of what I said was stated in post #28 and beyond....



AS for the oil pressure, early LS1's are known for oil pump failures. While your hot idle pressure is more than enough, it sounds like maybe the previous owner hasn't kept up on maintenance, and a replacement oil pump could be cheap insurance to save your high mileage long block.

Keep listening to PSU 98, sounds like he knows what he's talking about...

PSU 98

iTrader: (4)

Oh believe me, I'm far from being an expert here. But a lot of this is just "fundamental" stuff, and we all learn as we go

stefan256, if you're going to swap out the oil pump you may as well change out the cam while you're in there

stefan256

iTrader: (1)

yeh im thinking about it i dont know but this car feels alot stronger stock with the paper filter and catback exhaust, than my 00 z28 that had lt's and boltons etc so idk.