: What oil for my LT1 '94 Fleetwod?



425 Dual Quad
06-17-06, 04:51 PM
Hi Guys,
Hope we are all well. My '94 Fleetwood has the change oil light up on the dashboard.
No real problem but I'm in Ireland and I'm not sure of getting the right 5w30 oil. Ordinarily in England I would have put Mobil 1 in or Kendal but here in Ireland that is a little difficult.

The local motor factor tried to sell me some dodgy looking German branded fully synthetic stuff telling me it was spec'd for the latest Volkswagens [and turbo desiel ones at that]. I wasn't so sure and thought I'd do my research, especially at 55 euros a tub.
Any ideas please!

Is there anyone here running a RWD LT1 motored Cadillac in Ireland?? I've rumoured ther is a blue one in Dublin with a beige interior but that's it.

Thanks all and ahve a good weeked!
Nick

N0DIH
06-17-06, 05:24 PM
I am a fan of only CI-4 oils for my LT1. There is more ZDDP antiwear additive in those oils. I don't care if it is synthetic or not, it is still better on wear in high pressure areas like cam/lifters.

You don't NEED synthetic, it doesn't gain you anything significant. I run 15W40 Rotella T/Delo 400/Delvac 1300 year round. Works well for me. I am actually running Rotella T 30 weight now.

I think the oils in Europe are typically better spec'd than the US. But the newer US spec on oils (SM) has removed a significant part of the ZDDP to help with emissions (it coats cat converters). It is showing up in the US as a BAD thing on older cars with flat tappet cams (your LT1 has roller cam). I don't agree with the statement some say that if you have a roller you don't need the ZDDP. I am running it as long as it is available. If I have to use SM oil and add GM EOS, than that is what I will have to do.

Look and see what your local semi shop spec's for oil for the big over the road semi tractor/trailers. That is likely the best oil to use.

96Fleetwood
06-17-06, 05:24 PM
I run 10W40 regular Havoline oil in my 1996 LT1 Fleetwood. It has been running "dino" oil since new and does not burn a drop :thumbsup:

Rick186
06-17-06, 06:41 PM
Hello,

You may want to peek at the OIL CHANGE discussion farther down this BB.

N0DIH is dead on, backed up by a good friend who is a graduate engineer and the chief lube engineer of a mega corporation who agrees wholeheartedly with the statements made.

Thus, I'm now running DELVAC 1300, 15W-30 in my 1995 FWB with ~91,000 miles on it. And I expect that will be its lifeblood for as long as I own the car. (Or as long as I can keep getting DELVAC)

N0DIH
06-18-06, 03:24 PM
10W40 has changed a lot since the car was new. The problem is the big car manf have control in changing the oil specification, we don't. They keep moving it along to higher specs, but that doesn't mean it is better. And it isn't backwards compatible like they lead you to believe. In other words, if the spec for oil for your car was SG when new, and in 5 years the oil changed, they really don't care about your "old" car, they are spec'ing the oil for new cars that are coming out.

No, I am not claiming some conspiracy theory that they do that to make you buy new cars. But they have to consider what the EPA is forcing them to do. And it just happens that from SL to SM oil, it is bad for older cars, primarily with flat tappet cams, and more so, for ones with garden variety el cheapo "made in chain" tappets that are not made to the stds GM requires. So we are seeing a rash of failed lifters.

GM didn't allow for 10W40 in any car from around the early 80's, if not as far back as 77. It has too many additives that cause ring deposits. I have heard 20W50 was banned for the same reasons. GM went to all 5W30, 10W30 and straight 30 oils on most cars, if not all.

Honestly with oil still advancing, a 10W40 is a LOT better than it was when GM banned its use. So it might be ok.

I'll keep running CI-4 15W40 for now. Maybe go to Amsoil (10W)30 or 5W30 Series 3000 soon. If they are gonna kill off ZDDP more for the semi's, I will probably buy a large quantity of it just to sit on and have a good stock.


I run 10W40 regular Havoline oil in my 1996 LT1 Fleetwood. It has been running "dino" oil since new and does not burn a drop :thumbsup:

96Fleetwood
06-18-06, 03:33 PM
I am not too worried, one of my good friends just had his 1996 Impala SS turn 236,000 miles on the original motor and all he runs is 10W30/40 depending on the season :thumbsup:

If I can get 150K miles out of my stock motor, I will be more than happy... (and not because a 383 stroker is in the works).

Rick186
06-18-06, 08:34 PM
Hey, Elias . . .

You going to post 12 second quarters with that stroker?:)

96Fleetwood
06-18-06, 09:43 PM
Hey, Elias . . .

You going to post 12 second quarters with that stroker?:)

Maybe on a good day a 12.99 is possible on a all motor 383 stroker in a Fleetwood paired with some good gears, stall, and shift kit :thumbsup:

Johnny Bravo
06-19-06, 12:56 AM
I am not too worried, one of my good friends just had his 1996 Impala SS turn 236,000 miles on the original motor and all he runs is 10W30/40 depending on the season :thumbsup:
).
Great, but that's a roller cam engine. The risks to using the new SL, (and especially the SM grade) passenger car oils are primarily to older flat tappet engines, as mentioned. Furthermore, the grade changes are fairly recent event, mid 2004 I believe.

However, for a couple of dollars more why take the chance with any engine. :hmm:

425 Dual Quad
06-19-06, 11:04 AM
Hi guys,

Thanks for the info. At the risk of hijaking my chain away from quartermile times and back to oil spec !! :)

I don't think anyone ahd heard of ZDDP hereor any of the other brands you mention. I know I can get standard 10w40 Havloine here though.

I found I have an unused 4 litre can of 0w40 Mobil 1 in the shed. It is Fully Synthetic oil though and reading it is seems ti may have soem detergents in it.
I heard these are not the ebst thing to have in your opil in tehat they clean everything out, dump it back down into the pan, it then gets sucked up into the top of the motor and the bits get stuck in teh small oilways, block them up and bye bye motor.
Not the best really.

Is weight the critical thing here - I mean although the book [and oil cap] says 5w30 but if I can get the right spec of a differnt weight - 10w30/ 0w40 oil what should I use?
Am I better using the 0w40 Mobil 1 or a Havoline 10w40 or an unheard of 5w30??

Oh and it's only 4 litres so I'd have to mx it with somethng else to bring it up to quantity - probably whay it is still in the shed! - What is the refill quantity of the LT1, including new filter please - 5 litres?

Confused, advice please!!:confused:

Thanks Nick

Johnny Bravo
06-19-06, 11:54 AM
GM specified 5W-30 oil so they could squeeze the last bit of gas mileage from the engines in order to meet CAFE requirements.

In practice, it's way too thin for anything but the coldest weather.

Use the 0w-40 you have, add a can of 10W-30 synthetic and you should be fine. I think what you've heard about synthetic oil cleaning too well is exaggerated.

BCs71
06-19-06, 01:56 PM
GM specified 5W-30 oil so they could squeeze the last bit of gas mileage from the engines in order to meet CAFE requirements.

In practice, it's way too thin for anything but the coldest weather.

Use the 0w-40 you have, add a can of 10W-30 synthetic and you should be fine. I think what you've heard about synthetic oil cleaning too well is exaggerated.

I agree, what GM spec'd for the LT1 engines was in most regards for other reasons than the lifespan of the engine in mind. GM would like nothing better than for an engine to not last forever so they eventually can sell you another car.

There are websites specifically designed for auto oils, like bobtheoilguy.com or theoildrop.com or something like that. They have message boards with very qualified and knowledgeable people. Many folks have used oil analysis done on several different brands and weights of oils for each specific engine, including the iron-headed LT1. I suggest you check it out and see for yourself what is rated highly and see what is most convenient or available for you to purchase since you are overseas. Good luck!

425 Dual Quad
06-19-06, 05:12 PM
Thanks Guys,

I guess I'll use the 4 litres of 0w40 Mobil 1 tri-synthetic and add a litre of 10 or 15w30 to average out the low end viscosity to 5-ish.
Would that work??

Thanks
Nick