FAQ: Engine Oil - What type and change intervals?

In the 99 Riv I use the GM 10W-30 from the dealer.
The 70GS455 gets Rotella 10W-30.
The rest of the fleet gets Castrol 10W-30.

Bert

1998 Riv wrote:

We all have our preferences, in large part based upon our actual use of a particular brand/formulation/weight.

My recommendation would be to run a synthetic oil at the weight spec'd in your owners manual, and change it at whatever interval you are comfortable with. I've been testing my old oil at Blackstone Labs the last couple changes, and they don't want me to go over 3500-4000 miles, due to slightly elevated levels of coolant components. Not serious yet, but a looming problem. I need to swap my LIM gasket one of these days... I'm running Royal Purple 5W30 in winter, 10W30 in summer, per the manual's specs on weight vs ambient temps. It's expensive stuff, about $7/qt.

Just curious if you ever have to add any coolant ?

I have the kit from Blackstone and will send the oil from the 99 Riv when its time to change it.

Bert

Bert

Nope, have never had to add coolant. So I know there ain't much seepage. Just enough to show up in their testing at a very low level. I ran 3500 miles on the first 2 samples tested, and after the 2nd they told me I could try going to 4000 miles but would not recommend any longer than that.

1998 Riv wrote:

Nope, have never had to add coolant. So I know there ain't much seepage. Just enough to show up in their testing at a very low level. I ran 3500 miles on the first 2 samples tested, and after the 2nd they told me I could try going to 4000 miles but would not recommend any longer than that.

I know a lot of people consider the GM seal tabs to be very bad for these engines but in your case it might be just the ticket. I mean if it solves the problem great. If not, whats the harm.

Bert

Well I already have the aluminum LIM gasket here, so that's the fix I SHOULD be doing one of these days.

manofmany wrote:

I run the cheapest I can find.

I've put hundreds of thousands of miles driving all over the US and never had a problem with internals. Expensive oil is highly overrated. Of course this is just my opinion.

I actually believe this too. Synthetic is "better coverage", but were only talking a few more degrees for 3x the price. That being said, I still use full synthetic in 3 of my 4 motors. But 2 are marine motors running redline alot of the time and the last is the riv, which always gets driven hard.

I use the Mobile 1 5x30 all year long as well..

Purple royal leaves sludge behind. THE BEST is Valvoline VR1 racing motor oil. 50 wt. if you want your car to show u love on the street, dont put junk oil - it WILL catch up to you in the future!

straight 50 is too viscous for a daily driven 3800.

Reg Valv 10w30 for the last 140k miles. 5w30 for 3k miles last winter.

meant 40wt. but i see a lot of ppl here using 30wt? do you have to change your oil more often?

I use Mobil1 5w30 year round and change it at 5000 mile intervals. I could probably go longer but I don't.

96rivgirlla wrote:

meant 40wt. but i see a lot of ppl here using 30wt? do you have to change your oil more often?

No, it is what is recommended by GM. 10W30 in summer heat, 5W30 in our COLD northern winters. I might run a heavier weight oil if I lived in CA/FL/AZ etc.

I also use valv 10w30 but next oil change I'm going to swich to synthetic oil.

I use Valvoline Max Life 10W30..

Ok, before I go get paralyzed by sticker shock, any idea how much a rotation and balancing should cost?

I also have to get an oil change this weekend...idk if my Riv is running synthetic or not but I think I may have to pay the extra $20 for the high mileage/old engine stuff. The car's 13 years old, has under 90k miles on it, but I don't want to take any chances so I may run synthetic because of the engine's age. Any input?

You can rotate them by yourself with a jack & stands, and socket ratchet. A shop will rotate them for $20, but at that point, might as well just have them rebalanced for a little more.

Are you talking about high mileage oil, or synthetic oil? There is a high-mileage conventional oil that should be about the same price as regular. Synthetic oil a lot more expensive, and is great if you want the absolute most out of an engine performance-wise, but I don't see it extending the life of the motor. I do see it leaking out of small cracks of a high-mileage engine. I also seeing it costing you more, so that you can go extended periods without changing, and I don't think that's wise to do with a high-mileage engine.

Riight...so I should go with the conventional high mileage stuff. Is there any way to tell if it's running synthetic right now? Or would the mechanics be able to tell from the drained oil?

Only way to know for sure would be to send it for analysis ($25). Maybe someone else knows a way to tell?

I use regular conventional oil. I don't know what the high mileage stuff has in it - probably extra lubricant additives. Synthetic is fine if yo ucan afford it, I just find it a waste when I change my oil every 3k.

Hey Ilan -

about synthetic oil - depends on how old your engine seals are. Synthetic tends to leak out past the seals unless you've used it from when the seals were new. In my experience Mobil 1 does not do that so bad. I used Mobil 1 in my Riv since ~48,000 miles, no problems. I replaced rear main seal at ~89,000 miles when I had a tranny overhaul, and I (well, actually Doug at the dealer) replaced the front main seal a few weeks ago (~187,000 miles).

Albertj

I never thought motor oil could make my head spin like this...


I think the seals are still original...

Yeah, it's funny. I found that the inexpensive synthetics (WalMart sells a store brand synth, for instance) make your engine leak like a whizzing puppy if the seals have any age. I've switched 2 cars with under 50,000 miles to Mobil 1 with *NO* ill effects. I tried switching cars with higher mileage and they drip almost immediately.

If it is any consolation - if it was not dripping in the first place the drip stops if you switch back to dino-juice. (My experience with a 60,000+ mile Volvo).

So you *could* try it and see what happens.

Albertj

I'll stay with conventional high-mileage stuff, doesn't sound like I wanna take a chance.

IT's not like it runs out that fast. It's just that I don't want to BS about it either. In my experience, synth oil seeps pst old seals. It's great for older engines if you have replaced the seals.

If it means anything - one oil change I tried using synthetic Rotella in my car's engine (5w40) instead of the Mobil1 10W30. It was UnBeLieveable how fast that stuff started to leak. I chagned back to Mobil 1 after a week, and the leak stopped.

So - again from experience - you could try it and see what happens. In my experience Mobil 1 is least likely to leak, and if it does you can switch back and if your experience is the same as mine the leak will stop.

Albertj


Albertj

My experience has been that as long as the viscocity is right, it really doesn't matter what kind of oil it is. I believe there is no issue switching from Synthetic to Conventional and back again.

I have switched many older V8s to synthetic and never seen that start a leak. Viscosity is Viscosity, no matter what type of oil it is. Synthetic oils are also rated like conventional oils. They just claim higher milage capability, which doesn't prevent the oil from getting dirty.

I use Mobil1 and change my oil and filter every 5000 miles (easy to remember!). I also started using it at 50000 and now have 130000 with no oil related problems. I use 5w30 year round.