oil for a 3800 series II

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Jan 20, 2004
There have been quite a few posts on this engine, including my own. (L67). Turns out the 3800 is very easy on oil, and just about every oil has turned out great results. Chevron/Havoline works great for a dino, and the M1 and GC results look great too. I use 10w30 in the summer and 5w30 only for the coldest months(below 0). -T
I'm trying to decide what the best oil for my wife's Impala's 3.8..I've been using RP 5w30 in winter,10w30 in summer..The manual says the preferred oil is 10w30..In the summer the engine seems louder,noisier at start up and have heard quite a few conflicting stories about these engines liking an oil on the thicker side..Is M1 15w50 a candidate,or should I be using a 5w40??? [Off Topic!] I've been cruising this site for a while and only registered in january,but I applaud all the great members and some great info...I'm not up on all the jargon,where can I go for a crash course for stuff like cST,TBN ??? I'm so confused... [I dont know]
All the technical data is here BITOG, charts, graphs, etc. I use Amsoil 5W-30 in my '95 Olds 98, engine sounds fine, even if the oil is at the upper limit for a 30 wt.
I'm running 4 quarts of Delvo 15w40 & one quart of M1 SS 5w30 in my car this summer. I've more or less decided that I'll do 2 oil changes per year on the car, one in the fall and one in the spring. I have some Rot-T syn 5w40 (gallon) so that will go in this fall w/ a quart of M1 SS 0w30 or 0w40 for the Winter. 105k miles on the engine and it runs great, burns no oil what so ever. A previous poster was right, this engine is easy on oil.
As a member of a family that runs 3800 I must chime on. It is certainly a reliable engine that you can run almost anything in** (except a 5W20 LOL) M1 Trisynthetic 10W30 caused elevated noise, albeit harmless bases on oil analysis data here. M1 SS is pretty quiet. M1 15W50 was pretty smooth stuff, no irregular oil pressure either. Delo 400 15W40 HDEO, it liked that too, and winter starts were no problem! (quite surprising to me) Although I recommend a synthetic for better engine cleanliness. With all the oil hoopla on this forum, one thing we always have to point out is: It does not matter how superior your oil is if your engine is engineered/assembled/low durability badly. In the case of the buick lineage 3.8 engine family it is well designed and can give you many years of service if oem service paramaters are honared. Running synthetic is additional pride and peice of mind while you happily enjoy the great low end toruque [Smile]
Originally posted by outrun: As a member of a family that runs 3800 I must chime on. M1 15W50 was pretty smooth stuff, no irregular oil pressure either. Delo 400 15W40 HDEO, it liked that too, and winter starts were no problem! (quite surprising to me)
[Big Grin] [Big Grin] [Big Grin]
If this is the same motor that GMH sells here, 3.8Lts V6 Ecotec, I have it in a Holden and have used various oils including D1. At the moment on second interval of Motul 300v 5w-30. Winter here at moment and no noise problem.
Yes. It's the same. Holden has been using the 3.8 since the late 80s. I have three 3.8s. An 87 with 192k miles, an 88 with 210k miles and a 97 with about 60k miles. The 87 I've had for the longest. It's run M1 tri-syn and SS for about the last 70k miles with no engine problems. -T
I do almost all city stop and go driving and my 1st UOA showed Chevron 10W-30 sheared to a 20W rather quickly.I tried a 50/50 mix of Delo 15W-40 and Supreme 10W-30 and the results were better with the mix.No shearing , very quiet and no mileage ,power or startup or oil consumption problems at all.... mines a 2003 and both the oil cap and the owners manual say to use 10W-30.
The GM 5W30 v. 10W30 & 3800's revisited. At least for the series I & II here is what the manuals say in general. Series I was 10W30 factory fill. If you read the manuals on the viscosity v. temperature chart it shows 10W30 as the ideal one across the temp. band. However for something around 0 degrees and up and below it recommends 5W30.. The manuals say 10W40 not recommended, but from previous posts the consensus seems to be that this was just for CAFE credit. GM held to 10W30 until 1998-1999 when they started putting 5W30 fill caps on the V6/V8/4 bangers. The manual goes on to say that in extreme cold synthetic oil is recommended [Smile] I always found it interesting seeing the LS1's, 5.3L etc with a 5W30 cap. My gut instinct was always go heavy in these engines.
The 3800 and Northstar were the last hold outs for the 10w30 cap. Technically all GM engines call for 5w30 or 10w30. However 5w30 became the "recommended" oil in most temperatures a while back. The oil cap is a reminder for people who don't know how to look it up, the proper chart is in the owners manual. -T
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