OIL For LT1

v90hamm77 · #1 (**permalink**) 02-20-07, 03:54 PM

Hello fellow FWB owners. I just purchased my dream car. 96 Fleetwood Brougham. It has 97,000 miles on it and I was wondering what oil to use. The previous owner put Havoline 10w30 in it. Is that a good oil? What type of oil do you guys use? What about Castrol 10w30 High mileage? Do you guts use AC Delco filters or Fram?

Old Fleetwood · #2 (**permalink**) 02-20-07, 04:16 PM

Hi and welcome to the BB. Spend some time on back "issues" and you'll see a real gold mine of discussions about oil an some of the talk got pretty hot.
My personal choices - and they don't get much of an argument - are:
>Mobil-1 10-30 (the LT-1 is a de-tuned Corvette motor and they came from the factory with Mobil-1 if I'm not mistaken)
>AC or Wix Filters
>Same goes for Air Filters.
Fram once was a decent filter, but if you want some REALLY in-depth info on oil filters, dig deep into the research done by a guy over on allpar.com. (a Mopar site).
He was stunned to find how bad the new Fram filters were after playing with hundreds of them, slicing them open and all that stuff.

BCs71 · #3 (**permalink**) 02-21-07, 02:16 PM

Fram is usually considered the enemy since they had a rash of crap filters a few years ago. Probably changed now but th AC Delco filter is plenty fine anyway.

Quote below from Dwayne, on the forums, who has done extensive oil research for the B/D body LT1 engine. This involves used oil analysis (where engine wear is determined by used oil being sent to a lab).

"Best oil, if wanting to use Mobile 1, is 0w-40 or 5w-40.
Only problem with M1 is the most commonly used grades the 10w-30 and 5w-30 are too thin for this engine, this is specific to M1 other oils are fine in these weights and CASTROL syntec 0w-30 "made in Germany" has proven to be about the best for this engine, though most of the Syntec line is not worthwhile this one and the Belgian 5w-40 are returning good reports."

Old Fleetwood · #4 (**permalink**) 02-22-07, 08:55 PM

Very interesting result I got when I went to the Mobil Oil web site and punched in their recommendation for a 1995 Cadillac Fleetwood Brougham with the 5.7 motor.
Above Zero degrees in the winter, they recommend Mobil1 10W-30.
So I started looking around and went through their FAQ's. That's when it got really interesting and I found their 0-40 oil being recommended for Audi (!) and a few others.
Since I occasionally pull our 1,700 lb. PopUp RV, the 40 part of the multi-viscosity oil would be desirable. My only problem is finding the stuff at a decent price!
But something else I found was that ZDDP, a highly recommended additive for heavy duty applications, is, by Mobil's thinking, possibly a catalytic converter killer. Apparently the zinc constituent in ZDDP can - over time - poison the cat.
Something to think about.

XXL-VETE · #5 (**permalink**) 02-22-07, 10:44 PM

I’ve been using 0-W30 AMSOIL Series 2000 in everything I own for 10+ years now .. And AMSOIL filters .. It’s more expensive the dyno oil but it also goes 35,000 miles between oil changes ,.. I use to have oil analyst done but it always came back that the oil was still good “run another YEAR and retest “ so I just stopped testing .. Have never had an engine failure do to oil; Bad injector + Nitrous, Yes ; Oil No

Kenny

v90hamm77 · #6 (**permalink**) 02-22-07, 11:59 PM

Are you talking about regular or synthetic Mobil 1?

Old Fleetwood · #7 (**permalink**) 02-23-07, 12:26 AM

Synthetic - as in "distant cousin to antifreeze."

Hammondsix · #8 (**permalink**) 02-23-07, 08:07 AM

I thought Mobil1 was always synthetic as opposed to just mobil.

N0DIH · #9 (**permalink**) 02-24-07, 01:43 AM

I have some spreadsheets that compare some of the specs on the synthetic oils out there. I don't have a place to host it anymore, but if someone can, I can send it to them, just PM me your email....

v90hamm77 · #10 (**permalink**) 02-24-07, 05:14 PM

Hey NODIH I can't PM you my email because I haven't posted enough on this forum yet. I would really like to see those spreadsheets!

N0DIH · #11 (**permalink**) 02-25-07, 12:03 AM

Here is a printed version.

I am still updating it as I can, but I am not getting much good info from the suppliers that I can add to the spreadsheet that is meaningful....

N0DIH · #12 (**permalink**) 02-25-07, 08:25 AM

So basically what the chart shows is many if not all 0W30's are actually thicker than 5W30's. And most all 10W30's are thinner at hot temps than 5W30 and 0W30. So in the summer, you could see better mpg with 10W30 over 5W30. Bloody amazing isn't it....

As soon as it is over 30F I am going to 10W30.... My 301 Turbo Trans AM was spec'd at 30W over 30F and 10W30 below, no other grades allowed.... All the wonders of old SE engine oil....

Old Fleetwood · #13 (**permalink**) 02-25-07, 09:29 PM

N0DIH -
As long as we're talking about oil for our LT1's, what's your opinion of the Mobil site's statement about ZDDP being a potential Catalyst poisoner?
That goes double since I believe GM's additive is nothing but ZDDP in a can.
Am I correct on this?

N0DIH · #14 (**permalink**) 02-25-07, 10:31 PM

Yes, I do believe from what I have read that ZDDP does cause problems with catsm I think it coats it and makes it ineffecive.

Yes, GM's EOS is nothing more than ZDDP. I am going to just start adding it myself to my car and run whatever oil I want. Right now I have been favoring 15W40 Rotella T or similar. But for the extreme cold we had this year, I went with 5W30 Mobil 1 SUV/Truck oil, which is supposed to have better amounts of ZDDP, but that is rumor, nothing specific from Mobil 1.

Everyone seems to preach that German Castrol 0W30 is good, but honestly the TBN, Total Base Number is low compared to oils like Mobil1 and Amsoil. So it shows to me that they aren't the best oil to use. I prefer an oil with a very high TBN if I get a choice. TBN is the Ph of the oil being more base, so it can handles more acids for a longer amount of time. Higher TBN is best.