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jah

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Hi All it's me again,

I have a 1994 STS this is my first northstar. I've always had performance cars. I've been racing cars and rebuilding engines since the 80's. My engines have been 400 ci or better. My questions is i've always been running 20w50 and Lucus oil in my engines during the summer and 10w30 and lucus oil in the winter because of the heat in the summer and the cold in the winter. I never had a problem with this combination. I 've alway's put almost 200,000.00 miles on my engines before rebuilding, and even when i rebuilt the engines they still looked like brand new. Did the rebuild because of the milage. My question is because this is my first time with a northstar an i doing it harm by running 20w50 and lucus oil in the summer? one thing i have noticed since switching to 20w50 it is running 5-degrees cooler? :)

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I'm not a 100%, but the Northstar engine should run with 10W30 all the time.

OEM when it comes to these babys.

"Cadillac, it's not a car, it's an obsession"

-W.Kingdon

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I think what he's asking is if it will hurt it or not.. And I don't think it will, although I would still use 10w-30 all year around and probaly some lucas too. Lucas makes good stuff. What Guru is saying is that it's not necessary to use it but I think you might get a few more miles out of it using some lucas , although it will certainly make 200k without it. The coolant is the big thing with the all aluminum engines. I think the NS has pretty tight clearances (except around the oil rings.heh...darn oil consumption) so 20w50 isn't necessary at all. Older , larger, less 'tight' engines 20w50 would be just fine. I don't think it will hurt anything at all running it in NS but it's not necessary and it might get you a little worse gas mileage.

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I'd can't see any reason to use 20W50, or any reason to spend the money on the Lucas products.

The Northstar engine was designed, tested and validated for 10w30. Million of miles of experience including lots on this message board shows that with 10w30, your engine internals will outlast the rest of your car. These Cadillacs eventiually fail in many different ways, but if you do your resarch you will see that internal engine wear is not one of the common failure modes.

If your question is will running 20w50 hurt anything? My answer is it probably won't but it might. You'd have to find out on your own. Why bother finding out when there is no evidence that that shows that using 10w30 will be inadequate?

I have seen no evidence (other than the Lucas marketing hype) that Lucas products are in any way superior to the mainstream name brands.

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The only reason I would not use a 20W50 weight oil is the delayed pressure/flow of a thicker oil at startup.

We discuss the benefits of a thicker oil in hot weather and perhaps it's additional protection in a hot engine.

In reality more damage is caused to the engine during startup, than any other event.

Barry

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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Hey there. I use only 10w30 all the time. My 4.9 leaks everywhere while moving. My main concern are rubber bushings and water pump gasket - oil eats them alive... I bought some oil additive made by Bar's Leaks. Did aanybody try it? What else I can try without getting too much involved with the motor (I love my 4.9 Lit is very well engineere motor .just a little bit leaky) <_>

The saddest thing in life is wasted talent

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Hey there. I use only 10w30 all the time. My 4.9 leaks everywhere while moving. My main concern are rubber bushings and water pump gasket - oil eats them alive... I bought some oil additive made by Bar's Leaks. Did aanybody try it? What else I can try without getting too much involved with the motor (I love my 4.9 Lit is very well engineere motor .just a little bit leaky) <_<

Armen, where does your 4.9 leak oil from? If it is leaking from the oil cooler lines that connect to the oil filter adapter and radiator, you can purchase replacement O-RINGS to stop those joints from leaking. I know that you recently changed or worked on your radiator, once you detach those o-ring joints the o-rings need to be replaced or the connection will leak. In addition, there are o-rings behind the oil-filter adapter that can be replaced if it is leaking there. My 4.9 never leaked once I replaced all the o-rings. Mike

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My NS was leaking oil all over the freggin place until I resealed the half case.. Talk about an engineering f'up :) Ahh well at least it was an oil leak and not an engine detonation or tranny explosion

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;)

Armen, where does your 4.9 leak oil from?

Mike, you better asked where it did not leak :D

I am sure oil cooler lines are fine (I put new o-rings of course). As for the oil filter adapter, it definitely leaks and i am considering replacing the gaske, but... since it leaks everywher i am afraid it is not goin make much difference.

The saddest thing in life is wasted talent

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My NS was leaking oil all over the freggin place until I resealed the half case.. Talk about an engineering f'up  Ahh well at least it was an oil leak and not an engine detonation or tranny explosion

:lol::lol::lol: bigfoo, how's your water reservoure? (I mean the trunk) :D

The saddest thing in life is wasted talent

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;)
Armen, where does your 4.9 leak oil from?

Mike, you better asked where it did not leak :D

I am sure oil cooler lines are fine (I put new o-rings of course). As for the oil filter adapter, it definitely leaks and i am considering replacing the gaske, but... since it leaks everywher i am afraid it is not goin make much difference.

Armen, the 4.9 should not leak as your are describing, as a matter of fact having been on this board for close to 5 years now I guess, and having had a 4.9, your 4.9 is the first one I have heard have major leaks. You say it leaks everywhere, where? How are the valve cover gaskets? Are you leaking from the front on rear crank seals? The oil filter adapter uses square cut seals that have been known to leak. Also, I do believe that the oil pan can be removed if the gasket is leaking. Mike

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Mike,

It literally leaks from everywhere- the water pump is covered with a thick layer of oil. i do not care of pan gasket. The both cranc seals, and the valve cover are among the bad guys as well. Well, the good news is I am the only one with leaking 4.9L! Still love this motor! Big, smooth real American engine! Guru, can you hear me? :D

The saddest thing in life is wasted talent

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Mike,

It literally leaks from everywhere- the water pump is covered with a thick layer of oil. i do not care of pan gasket. The both cranc seals, and the valve cover are among the bad guys as well. Well, the good news is I am the only one with leaking 4.9L! Still love this motor! Big, smooth real American engine! Guru, can you hear me? :D

I replaced my valve cover gaskets a bigger job than I anticipated especially the rear but I stopped oil from leaking down on the exhaust manifolds. Doing that job however allowed me to really look things over as I also did the water pump at the same time. Oil can leak down on the water pump only from the valve cover gaskets a believe.

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Mike,

I know it's a lot of work to get rid of all leaks. I want to remove the serpentine belt and clean the waterpump with some grease. I will probably take care of oil filter adapter gasket (if I do not need to reconnect all the connections). That' s ok, let it leak. After all, all good things leak :D

The saddest thing in life is wasted talent

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