My 97 lt-1 has 188K miles and it has a newer comps cam which is broken-in now and I was wondering which oil below is good. I live in Texas BTW so im really leaning towards the #2 oil since the weather here and cars mileage.


#1 Castrol gtx high mileage semi-syn 10W-30
#2 Castrol gtx high mileage semi-syn 5W-40
#3 Rotella T-6 synthetic
#3 rotella diesel oil (For the extra zddp)

 

Your LT-1 has a roller cam. You do not need oil with the extra zinc, any 5w-30 will work. Only on the flat tapped motors do you need the diesel oils with the extra zddp or after market oils.

 

Full synthetic oil lives twice as long as conventional, and therefore is cheaper to use. Not to mention synthetic doesn't sludge up like conventional does/can, it does just the opposite.

 

Ok thanks. Oh and my oil pressure gauge reads kinda low as In barely above the red line while idling and around 40psi while cruising... So should I switch to a mechanical gauge or just replace the sender? Thanks agin

 

Is the low oil pressure a new development? You can replace the oil pressure switch, it's possible it's bad and giving an incorrect reading. I've had that with a couple of my cars in the past. If pressure stays the same after that, you probably have some bearing wear issues. If going to a higher viscosity raises your oil pressure, you'll know you very likely have excessive bearing tolerances.

 

Go for either #2 or #3. #3 is also a 5W-40 last a I checked. Living in Texas, I wouldn't be afraid to use 20W-50 during the summer. Castrol also makes a 5W-50 that's a full synthetic that'd do nicely.