2007 Pontiac Grand Prix base model with the Buick 3.8 engine with 225k miles on it. new to me. I'd like to go full synthetic for all the benefits, but there are people like SeanR on this thread: https://forums.aaca.org/topic/198781-3800-and-synthetic-oil/ who say it has caused massive leaks. but that was back in 2012. is there an explanation for why I should dismiss this fear, or have anecdotes like this not been fully explained yet?
synthetic for 2007 buick 3800 engine?
- Thread starter BumperBozo
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It is possible yet very unlikely, I would run whatever full synthetic you like no worries. Worst comes to worst you run a high mileage oil.
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I used Castrol Syntec for most of my 1987 Olds Trofeo's 3800 350,000 miles. Never a single leak at all.
I have 3 cars with the 3800, a LeSabre, a supercharged Regal and a Bonneville. All have gotten synthetic oil since I bought them years ago and none of the leaks have gotten any worse. They are all seeping from the front seal which is common I think. But really didn't develop any new leaks or any increased consumption. I have used all brands (whatever is on sale or in my stash) including mixtures of thick and thin oils to reach a good final viscosity.
What I would recommend is using a high mileage oil because it can help condition seals if they are in bad shape. While it may not help anything, it won't hurt anything either. But I can tell you that the engines don't mind a synthetic. It has been said before that these engines prefer clean oil over high quality oil. If you are planning to go synthetic to go very long intervals, this is probably not the engine to do it with. I usually go by the oil monitor since my cars have it or 7,500 miles. Often times it hasn't asked for a change yet when I do the oil change.
What I would recommend is using a high mileage oil because it can help condition seals if they are in bad shape. While it may not help anything, it won't hurt anything either. But I can tell you that the engines don't mind a synthetic. It has been said before that these engines prefer clean oil over high quality oil. If you are planning to go synthetic to go very long intervals, this is probably not the engine to do it with. I usually go by the oil monitor since my cars have it or 7,500 miles. Often times it hasn't asked for a change yet when I do the oil change.
If you’re worried about that despite the oil company technical information saying it isn’t true, then maybe a high-mileage oil would be best:
www.mobil.com
High mileage motor oil | Mobil™
High mileage engines – those with more than 75,000 miles – face a number of potential problems that high mileage oil is specifically formulated to address.
www.mobil.com
I had an '06 Lacrosse with that same 3800 S3 for a few years, and anecdotally it did use more oil when using synthetic. But I just watched it and kept it topped off; no big deal. The times I used VWB/Castrol blend, I noticed lower oil use. If I'd kept the car, that's probably the route I'd have gone.
With my '03 Park Avenue, going to synth (5W-30 Castrol Edge which I got on sale) aggravated the small leak or oil consumption I saw on conventional: something like 2 quarts lost in 4000 miles. When I went back to conventional, the consumption returned to its former level of about 1 quart in 5000. And my car had only about 90K miles on it when I tried that.
I'm not sure if HM synthetics were widely available back then (around 2010?). If they were I probably thought them more expensive than I wanted to pay.
I'm not sure if HM synthetics were widely available back then (around 2010?). If they were I probably thought them more expensive than I wanted to pay.
With 225k I'd try and find out what oil got it there and keep using the same. I can say my 3800 in my 08 Lucerne started using a little oil when I switched to synthetic so I'm going back to a blend, just don't know which one yet, leaning towards Maxlife red.
i don't know what has been used in it thus far, just that the oil change were done on time.
so, say it has been filled with high mileage oil, and i end up switching to conventional or blend that is not "high mileage". would it then reverse the effects of the high mileage additives? and would I then be able to re-reverse them by going back to high mileage?
so, say it has been filled with high mileage oil, and i end up switching to conventional or blend that is not "high mileage". would it then reverse the effects of the high mileage additives? and would I then be able to re-reverse them by going back to high mileage?
