Curious what would be the recommended oil fill for a Buick 401 Nailhead engine with 98k miles. I am 99.9% certain that internally it is untouched original from 1965 in my knowledge of the car, and there is nothing to indicate that it has had any work done to it. In researching I've pretty much gone in circles between Rotella T4, Super Tech Heavy Duty Diesel, Valvoline VR1, Brad Penn, Mobil 1, a good amount of zinc is important, zinc doesn't matter at this mileage, any oil has enough zinc to be sufficient, do use zinc additives, don't use zinc additives, and so on. Most of the forum posts on this topic are getting older at this point (mostly late 2000's-early 2010's) so some of the info given is sometimes no longer relevant or accurate. The car isn't driven in winter and only will get 3-4k miles a year at the very most, being driven on nice days. I've figured sticking to conventional is best as it doesn't have any major leaks at this point so I'd rather not dump synthetic in and find out several leaks have now opened up. My initial plan was Rotella T4 as that always seems to be the go to with all the "vitamins and minerals" for an old engine but then after reading that it was and now isn't gas engine rated (I think, haven't had a chance to look at a bottle), I've been reconsidering as a carbed engine is going to have a lot more gas contamination in the oil, etc. I don't plan on doing any engine work as it seems healthy at this point so keeping in it's current condition would be great.
Buick 401 Nailhead Oil
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Oil is so much better these days that anything you put in there is going to be better than what it was designed for including HDEO. It's hard to go wrong provided that there is enough viscosity to maintain sufficient oil pressure. Clean and full is the most important thing, here. At the rate you're driving it, you won't rack up enough miles to wear it out, regardless of the oil you put in it, before it's time to hang up your keys and turn in your driver's license.
Valvoline VR1 10W30 would work well in that engine
I hope that I am saying this correctly...
Don’t be afraid to use synthetic oils, as most of today’s synthetic oils are of a Group III chemistry which is Hydro processed-pumped out of the ground motor oil. It’s the Hydro processing that changes the chain molecules to rival the PAO synthetics.
So the synthetics that we knew of years ago(although very available and brought up to modern standards) that we thought of as cleaning so well that they create leaks, is more the exception than the rule. Sure there are still Group IV(PAO) and Group V(esters), but you’d almost have to look specifically for those.
I like the idea of Rotella T6 full synthetic in a 5W40 grade.
Also be cautious, but I’m not saying not to use it, of Valvoline VR-1 as it is a racing oil (and to my understanding) has the additive package for just that, not for the normal oil change intervals(OCI) as we know OCIs. Others may know better than I.
Don’t be afraid to use synthetic oils, as most of today’s synthetic oils are of a Group III chemistry which is Hydro processed-pumped out of the ground motor oil. It’s the Hydro processing that changes the chain molecules to rival the PAO synthetics.
So the synthetics that we knew of years ago(although very available and brought up to modern standards) that we thought of as cleaning so well that they create leaks, is more the exception than the rule. Sure there are still Group IV(PAO) and Group V(esters), but you’d almost have to look specifically for those.
I like the idea of Rotella T6 full synthetic in a 5W40 grade.
Also be cautious, but I’m not saying not to use it, of Valvoline VR-1 as it is a racing oil (and to my understanding) has the additive package for just that, not for the normal oil change intervals(OCI) as we know OCIs. Others may know better than I.
I don't think you can go wrong with any of your choices.
I would lean towards an HDEO (diesel rated) for the higher ZDDP and the better detergents, and the racing oils, like VR-1 would have similar benefits.
I would also change it annually. One of the big risks in older cars, like yours, is that the oil they ran wasn't very good, and you may have some deposits/sludge internally. So, if they're being dissolved by your new oil, then you want to get them out of there periodically.
The 401 wasn't a high lift cam, so it's not going to need excessive ZDDP.
Send pictures of that great car!
I would lean towards an HDEO (diesel rated) for the higher ZDDP and the better detergents, and the racing oils, like VR-1 would have similar benefits.
I would also change it annually. One of the big risks in older cars, like yours, is that the oil they ran wasn't very good, and you may have some deposits/sludge internally. So, if they're being dissolved by your new oil, then you want to get them out of there periodically.
The 401 wasn't a high lift cam, so it's not going to need excessive ZDDP.
Send pictures of that great car!
I would use HDEO 5w40 or 10w40. Having own this car a few other early Rivs My only real concern is the old rope main seals, they may leak with any oil at that age. A larger concern when I had mine was the valve seats running no lead gas, I had hardened seats installed.
Ok, a couple notes:
1 - That series engine, unlike later Buick engines with the oil pump in the front aluminum timing cover, has a decent oil system. If you are not experiencing low oil pressure at idle and you drive "normal" 10w30 is what I would choose. If you think the engine is worn excessively or you have oil pressure issues (light flickers on at idle or gauge pressure is low), then 10w40. If you have trouble finding 10w40, then seek 5w40.
2 - Valve spring pressures, even when that engine was new, are not severe therefore you don't need any additional ZDDP added or a special ZDDP heavy oil. I personally would use normally available off the shelf oil. I do in my existing classic car and the other ones in my signature that I have owned. If you want a higher ZDDP oil, I have used VR1 (the conventional one) and would recommend that. My issue with VR1 was only ever availability, you might have better options than me. I have had high spring pressure valvetrains in my lifetime and in those cases I have sought out and run higher ZDDP oils eg. VR1, Driven, Redline etc.
3 - Conventional or Synthetic... I swapped all my old cars over to synthetic when the pricing became pretty close between the two. I have never experienced a negative effect from synthetic. Do whatever is right for your pocket book and availability. I like Castrol GTX or Pennzoil Yellow Bottle for conventional and have used both with no issues. I use M1 and Pennzoil Ultra in synthetics currently but there are also many other fine choices.
4 - I have used the diesel oils that are dual rated (Rotella T5 was the last one in my Chevelle). No bad experiences but if a strictly gas engine rated oil is available I would use that first.
5 - Carb engine... yeah that is a reality with these old cars. Mine are always fat and rich at idle no matter how I tune them or how healthy they are, some are eye watering rich even. It is life. Plus, most of my driving is low speed cruising so, fuel dilution is a concern. I follow the manufacture's guidelines of the era on drain intervals even though I am using a modern oil. So far so good.
What car is this engine in? Riviera? GS?
1 - That series engine, unlike later Buick engines with the oil pump in the front aluminum timing cover, has a decent oil system. If you are not experiencing low oil pressure at idle and you drive "normal" 10w30 is what I would choose. If you think the engine is worn excessively or you have oil pressure issues (light flickers on at idle or gauge pressure is low), then 10w40. If you have trouble finding 10w40, then seek 5w40.
2 - Valve spring pressures, even when that engine was new, are not severe therefore you don't need any additional ZDDP added or a special ZDDP heavy oil. I personally would use normally available off the shelf oil. I do in my existing classic car and the other ones in my signature that I have owned. If you want a higher ZDDP oil, I have used VR1 (the conventional one) and would recommend that. My issue with VR1 was only ever availability, you might have better options than me. I have had high spring pressure valvetrains in my lifetime and in those cases I have sought out and run higher ZDDP oils eg. VR1, Driven, Redline etc.
3 - Conventional or Synthetic... I swapped all my old cars over to synthetic when the pricing became pretty close between the two. I have never experienced a negative effect from synthetic. Do whatever is right for your pocket book and availability. I like Castrol GTX or Pennzoil Yellow Bottle for conventional and have used both with no issues. I use M1 and Pennzoil Ultra in synthetics currently but there are also many other fine choices.
4 - I have used the diesel oils that are dual rated (Rotella T5 was the last one in my Chevelle). No bad experiences but if a strictly gas engine rated oil is available I would use that first.
5 - Carb engine... yeah that is a reality with these old cars. Mine are always fat and rich at idle no matter how I tune them or how healthy they are, some are eye watering rich even. It is life. Plus, most of my driving is low speed cruising so, fuel dilution is a concern. I follow the manufacture's guidelines of the era on drain intervals even though I am using a modern oil. So far so good.
What car is this engine in? Riviera? GS?
Thanks for the recommendations. Is Valvoline MaxLife synethic blend a good choice if wanting try and stave off future leaks? I've used that in the past so slow or stop slow leaks in newer engines and liked it. It does currently have 10w40 in it figuring that it's probably a little tired. I do have VR1 available locally but it's only in 50 wt or 20w50, so I'd have to order 10w30 to get that. If it were available in the 10w30 locally I'd probably go that route. Doing a few short drain intervals to clean things out and then just doing a yearly oil change is likely how I will do it. It's good to know that it's not super picky, and I had read elsewhere too that these engines do have good oiling systems so that's reassuring that it should have a good amount of it's life left.
My enemy in high school had a Riveria. My 70 ElÇamino with it's 300/350 didn't stand a chance against the 425 with 2 carbureators and it's switch pitch converter.
VR1 20W-50 would probably be unnecessarily thick but it won't hurt it, just be gentle on the throttle before it's warmed up.
Mobil 1 15W-50 would also be a good choice and not as thick when cold.
Mobil 1 15W-50 would also be a good choice and not as thick when cold.
For the well healed, but a dreamer seller:
1965 Buick Riviera GS | eBay
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I owned a 65 GS as shown but in the color of the OP. Sold it well running unrestored, but all original, for one daughters college expenses.
Paid $4500 in 1991, sold it for $5500 in 1998. Not a good investment but I had fun owning it. The market for these cars really took off after I sold it.
Note the dual armrest handles among many other unique features.
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I would keep it simple Valvoline white bottle 10/30 it's not a blend straight dino
This ^
As others have said, the valves could be somewhat sunk in the heads, depending on mileage. I bet that timing chain is getting pretty droopy...
Here's what I run in my 60's classics:
Here's what I run in my 60's classics:
I guess I should say that the car has been gone through by a previous owner/mechanic and had most things it could or would need after all these years replaced. Shocks, brake shoes, wheel cylinders, brake hoses and lines, springs, fuel pump, water pump, plugs, wires, cap/rotor, points, etc. Lots of little things that have added up to make it a very nice driving car that doesn't need much work. That being said, I would assume the timing chain has been done already at this point based on how thoroughly and carefully it has been cared for, but haven't checked it yet (and definitely will).
I did find that I am able to get Valvoline VR1 10w30 in 5qt jugs at Walmart here, single quarts are 20w50 so doing a 5qt jug and a single 20w50 would get an oil change a little thicker than all 10w30 if it is needing that (haven't seen it with 10w30 in it yet to see if it will turn the low oil pressure light on at a hot idle). I am also able to get Rotella T4-T6 at Walmart for $16-$24 a gallon so that is definitely an option, too. Walmart used to have the Castrol Classic as I've looked at it there before but they must've dropped it as I'm not seeing it or an empty space for it anymore.
I did find that I am able to get Valvoline VR1 10w30 in 5qt jugs at Walmart here, single quarts are 20w50 so doing a 5qt jug and a single 20w50 would get an oil change a little thicker than all 10w30 if it is needing that (haven't seen it with 10w30 in it yet to see if it will turn the low oil pressure light on at a hot idle). I am also able to get Rotella T4-T6 at Walmart for $16-$24 a gallon so that is definitely an option, too. Walmart used to have the Castrol Classic as I've looked at it there before but they must've dropped it as I'm not seeing it or an empty space for it anymore.
It does have lead substitute mixed in with the gas at each fill up. Currently slowly using up a bottle of CD2 concentrate, not sure what to switch to when that's gone but its probably 75% full so it'll be a while.
CharBaby mentions the additive package on the VR1 and running regular OCI's, which in this case is realistically going to be 2-3k miles on a yearly oil change, perhaps 4k at the most. Are there any concerns with running VR1 at a somewhat regular interval instead of perhaps after every outing in a race application?
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Just use a Euro oil…. 5w30, 0w40 or 5w40. Easy to find and plenty of zinc.
No problem mixing VR1 10w30 and 20w50, a quart of 20w50 ontop of the 10w30 will make it more or less a 10w40 which is fine.
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