1994 Pontiac Grand Prix 3.1 L - Oil recommendation

Messages
17
Location
Idaho
Hello, I recently acquired a 1994 Pontiac Grand Prix SE 3.1L, with 109,000 original miles on it. It's been sitting for a little over a year. We have taken it to the mechanic and replaced a few belts and parts. We've put about 1000 miles on it so far, and is on its second oil change, soon to do a third. We have been using 5W-30, conventional Pennzoil. My question is should I continue to use conventional for a couple more months, move to a semi-synthetic, or dump some High Mileage oil in it, because of age. The car has not used any oil, nor has any leaks. Any feedback would be appreciated.
 

Nick1994

$50 Site Donor
Messages
13,301
Location
Phoenix, AZ
It all depends on how often you want to change the oil and how many miles you drive. I say go ahead for a synthetic, and if it isn't leaking or consuming I see no need for a high mileage oil. I know some 3.1Ls have intake manifold gasket issues. I'd get that replaced before doing much else
 
Messages
8,306
Location
Grand Rapids, MI
We had a 3.1 in my mom's old 2003 Malibu that we sold with 150,000 on it. We used Valvoline conventional for the first 50k and I then used whatever was on sale (including some synthetics) and the engine was spotless when it was sold. My sister took it over for a few years and I started using synthetic in it because she wasn't any good at remembering to get the oil changed. In short, I would just keep using what you're using if it's working for you. Aside from the piston slap and intake manifold gasket, it was a very reliable and somewhat powerful engine. You can't really go wrong with any API SN rated 5W-30 in that engine.
 
Messages
1,313
Location
Alaska
You're over thinking it. You dont need to change the oil 3 times in a 1000 miles to clean anything. It's just a waste. Get the "whatever is on sale name brand" 5w30 you can and change it every 5k miles.
 
Messages
693
Location
PA
These engines seem to do well with Rotella T6 also, I've switched two (that a friend owns) over to T6 and stopped an oils consumption issue with one and made both run and sound very smooth and quiet. FWIW; these engines are know to toss rod bearings, I think most of that is caused by people not servicing the DEX-[censored] coolant...
 
Messages
8,306
Location
Grand Rapids, MI
Originally Posted By: ThirdeYe
We had a 3.1 in my mom's old 2003 Malibu that we sold with 150,000 on it. We used Valvoline conventional for the first 50k and I then used whatever was on sale (including some synthetics) and the engine was spotless when it was sold. My sister took it over for a few years and I started using synthetic in it because she wasn't any good at remembering to get the oil changed. In short, I would just keep using what you're using if it's working for you. Aside from the piston slap and intake manifold gasket, it was a very reliable and somewhat powerful engine. You can't really go wrong with any API SN rated 5W-30 in that engine.
I re-read my post and want to add a little "tip" I learned while maintaining the 3100 in the Malibu. When using the over-sized PF-52 sized oil filter, I put in 5 quarts instead of the recommended 4.6 quarts most of the time. More media + more oil capacity = win. I'll be doing that on the next oil change in the Firebird as well.
 

Galantboy

Thread starter
Messages
17
Location
Idaho
Originally Posted By: ThirdeYe
Originally Posted By: ThirdeYe
We had a 3.1 in my mom's old 2003 Malibu that we sold with 150,000 on it. We used Valvoline conventional for the first 50k and I then used whatever was on sale (including some synthetics) and the engine was spotless when it was sold. My sister took it over for a few years and I started using synthetic in it because she wasn't any good at remembering to get the oil changed. In short, I would just keep using what you're using if it's working for you. Aside from the piston slap and intake manifold gasket, it was a very reliable and somewhat powerful engine. You can't really go wrong with any API SN rated 5W-30 in that engine.
I re-read my post and want to add a little "tip" I learned while maintaining the 3100 in the Malibu. When using the over-sized PF-52 sized oil filter, I put in 5 quarts instead of the recommended 4.6 quarts most of the time. More media + more oil capacity = win. I'll be doing that on the next oil change in the Firebird as well.
Thank you for the suggestion. I didn't realize I could go to the oversized filter. I'm gonna check to make sure it specs out for my car. And when you say PF-52, I'm assuming the brand AC Delco? I actually, was doing some research on oil filters, and like the OEM AC Delco, but was going to pick up the size specified for the car.
 
Top