: Oil for Northstar 7.5 or 8.0

03-24-04, 05:23 PM
but first a funny story of my first oil change for my new DHS:

I do my own oil changes and the first oil change I did on my caddy a few days after I got it reminded me I was in a different league. ( see http://www.cadillacforums.com/forums/showthread.php?t=9958 for previous car history ). First off, my hydraulic jack which could hoist my Camry with ease, couldn't lift the Deville.

Ok..need new jack.

Anyway I managed to be able to slide under the car just enough to reach the oil pan plug and proceded to drain the oil. After 30 or 40 seconds I'm lying there thinking..this flow is still going as strong as when I first removed the plug. Needless to say I made a mess in my driveway. The oil pan I normally use didn't have enough capacity to hold the caddys oil.

Need new oil pan.

So I clean and tighten everything back up and proceed to get the oil I had left from an earlier case and start to pour them in ... 3...4...annnnd 5. That should do it...wright...wrong. The dip stick was still bone dry. Ok I forgot this is a big engine, let me grab another quart. Still nothing registered on the dipstick. Now I've worked In a shop before and I'm no stranger to oil changes but I rarely encountered engines that take more than 6 quarts of oil so I was skeptical about adding more because I didn't want to overfill it. So now I need all new equipment and need to keep 2 cases of oil. I wound up putting 7 quarts in, and have read varying reports that range between 7 - 8. Maybe I'll settle for 7.5 next time. Any thoughts?

03-24-04, 05:31 PM
The pan (or sump) holds 7 and then another 0.5 for the filter. A lot of us just use 7 for an oil and filter change. Remember, the dip stick is calibrated for HOT oil.

03-24-04, 05:32 PM
I've read more than once here that the top of the cylinder walls have a very aggressive cross-hatch pattern in them to catch oil to keep things nice and lubricated.

However, the downside to this is that it will eat a quart of oil every thousand miles or so due to it burning up in during normal combustion.

The northstar is an oil hungry beast. Just keep feeding it and you'll be all set. :)

03-24-04, 05:40 PM
I check oil level after driving it for a while. First I get it on level ground then I let it sit for about 20 minutes before checking the dipstick. I think that's the factory recommended way of checking it.

Mine uses a quart about every 1600 miles.


03-24-04, 10:10 PM
http://service.gm.com/gmtechlink/arcv_pdf/5_02_e.pdf Go to page 4. It is 7.5 qts. I pour 7.5 quarts in my car at a change, then note where that is on the dipstick cold. This way I can tell better where the level should be. I hate checking it hot because I never know if all the oil drained down yet. Though I do sometimes check it this way.

El Dobro
03-24-04, 10:34 PM
I go with the 7.5 quarts with the oil and filter change too.
Watch your oil consumption until you get an idea of how far your engine can go on a quart. Mine vary. The 98 gets around 1500 miles to a quart while the 93 is actually doing around 3500.

03-24-04, 10:46 PM
I don't usually change the oil on my daily drivers, myself. But I will with the Caddy! Holy cow, my first oil change nearly put me over the edge. I got the bill and had sticker shock. Then I looked at how much oil it took (I use synthetic) and the picture became clearer. Wow.

03-25-04, 10:49 AM
I changed my own oil the other day and put 8 in .... I'm hoping maybe to burn some out..but even after a 1000mi road trip and what appeared to be a small oil leak. the computer still didn't register low. The leak has stopped on its own. but I still don't think I'm eating oil. I'm sure this isn't a bad thing. On an engine that normaly does... could it be? anyway. The mysterious start then stop of the oil leak kinda scares me. I'm not sure what it is.

03-25-04, 11:17 AM
Why do you think you have an oil leak? You can see oil leaking? I think that some of the oil consuption that people see is brought on by overfilling the engine. It takes 7.5 quarts, but many people put 8, 8.5, or even 9 quarts in (there was an Aurora guy who said his dealer swore the 4.0 took 10 quarts). This may be why people think it burns oil readily. The engine gets overfilled, burns off the overfill, and it seems it is consuming oil. Not that no engines ever are just consumers, but I think it gets overinflated a bit due to this. From what I've seen on the Aurora side of things, the folks that change their own oil, put 7.5 quarts in, and realize where this lines up on the dipstick don't tend to have nearly as many complaints about oil consumption. Just an observation.

I suspect the long change intervals also contributes as some people get upset (not anyone here or anyone in particular) that it uses a quart of oil between changes, and they usually mention their previous car didn't need oil added. But a car that burns .5 quarts in 3,000 miles won't need oil added, while one that burns 1 quart in 7,500 miles will. But this is hardly a sign of one engine being better than the other.

Just thoughts, not directed at anyone or addressing anyone in particular. :)

Anthony Cipriano
03-25-04, 01:31 PM
The correct oil fill volume is 7 quarts in the sump and 1/2 quart for the dry filter. At a change the 7.5 quarts is exactly right. That was the design volume for the sump and filter. The Northstar runs more oil in the sump to meet the cornering starvation requirements. The sump is designed for this oil volume.

The "low oil" message will come on at 2 to 2.5 quarts low. So, I wouldn't expect a "low oil" message for quite some time after a change - especially if 8 quarts were put in. The system is validated to meet all the starvation and high RPM operation limits up to the point that the "low oil" light comes on. In other words, the system will perform fine with 4.5-5 quarts in the sump. In normal driving that is all that is required and no engine damage will occur even in spirited track driving (although the lifters will get noisy due to air injestion on the track at 5 quarts).

The stick is designed to be read with hot oil. If you put in the 7.5 quarts at a change (including filter) and start the engine for a moment and then shut it off and check the oil it will ususally show about 1/2 quart low. That's normal. Leave it alone and check it hot after driving hard and it'll be "full".

03-25-04, 02:55 PM
7.5 it is...thanks for the info and Aurora40 for the link. Just got the wife a 98 Expedition yesterday which I think takes 6. I'll have to stock up on oil, maybe a few 5 quart jugs and a case of singles should do.

Now let me make my way over to the "Northstar Stalls on restart thread"...my DHS took three tries to start after going out for lunch today. It did this yesterday as well. I'm not going to start complaining just yet ( we are practically still on our honeymoon and I'm willing to make up for any past neglect inflicted by her X, but this B!T(H is too young and looks too good to be acting so ugly ) . It seems almost to coincidental that It is acting up like this just over 50k - anyone have a conspiracy theory?

I had it in just after I purchased it with 48k for the Service Stability System warning in which the dealer replaced some steering module and they also performed my seatbelt recall thing under warranty as well. Let them tell it, everything looked good at the time, I wonder if everything still looks good when I go back...

03-25-04, 07:34 PM
I know it was leaking because you could get under it and see that it was drippiing a little. but that was before the oil change. Also before the oil change it quit leaking. I first noticed it when the pavement was wet and when the oil hit it it disperced. I came out after being parked for a few hours and it had a rainbow circle about 4ft accross. I checked it on dry pavement and it was leaking. But it seems to have stopped.

03-25-04, 11:05 PM
Weird. Is it possible it was leaking from the filter or from the plug? Maybe that's why it stopped after the change? Any time I've changed oil on a car that got serviced at a shop, the filter feels like it was put on with an impact wrench. I'm always surprised that shops don't have chronic complaints from people about leaks. I don't know how they don't crush the gasket all to hell...

03-26-04, 08:44 AM
The funny part was that it stopped before the oil change. And when I did the oil change the filter was clean. Leaving me to believe its the plug or maybe gasket....but why would it quit?? I guess I'll just have to take it to the hobby shop here on base and put it up on the hoist and find out where it was comming from... Even if it was an intermittant problem. I still want to know what it was so I can keep and eye on it in the future.