Do you lift the rear end higher than the front when draining the oil?

 

No, No, No, No,!
The car must be level and after you have removed the drain plug and filter you must let the oil drain for at least 7 1/2 minutes. Before you close every thing up and and start to add fresh oil!
Tim

 

That's what I do!
Fred K.

 

That is not true! The C5 should be a few inches higher in the rear than the front, but not more!!

 

Check your manual.
The dealer uses a 2 post lift there's no safe way to tilt the car on a two post lift.

 

I have never seen a dealer tilt a car to drain the oil better or faster, no matter what design. Fact is that the C5 pan is entirely flat and the drain plug is on the front. A slight incline of the rear helps to drain it faster and more complete even though it is not neccessary or required.
.

 

There are some very competent techs working for dealerships, and there are some young guys with not much experience working there also. Which ones get the oil changes? The manual states to raise the car and make it level then drain it for at least 7 1/2 minutes as you stated. I just had my oil pan off and had a birds eye view of the oil pan and sump assembly. I can tell you that with the rear of the car slightly higher than the front, the pan will drain more completely. However, If you do that then some the oil at the top of the engine may not get to the drainage ports.
What I do, is run the engine untill warm (oil at least 140 degrees). Then raise and keep level for 20 minutes. Then slightly raise the rear. I have a 2 post lift. What I do is put a 1 ton under hoist lift under the rear crossmember until the car raises about 2" back there. The car still remains on the rear jack points, but just slightly. This give the oil pan a very slight pitch to the drain plug. Then I remove the drain plug and say ouch, that's hot. Then I let it drain for 45 mins.
This is extreme oil changing, but it is what I do. I'm sure if you keep it level and do it by the book you will be fine. I probably get about 2-3 ounces more my way, but since I have the tools I do it. I still use 6 quarts and 1/2 for the filter. BTW, I fill the new filter up first before I install it. That way there is less air in the system when you fire it back up.

 

Drain the oil with it level and then lift the rear and you will see why raising the rear is good advise. Sid.

 

No. I lift mine on my dads Rotory lift and we keep it all the same.

 

I back mine onto my Kwik-Lift, so the rear ends up about 1.5 inches higher than the front. 0 Problems after 4 oil changes on my 2004 coupe. After, there is no visible presence of old oil when I look at the dipstick. When it was level, I could see a bit of dirty oil on the dipstick still. Also, I don't do the 7.5 minute thing, I usually just let it sit for about an hour while I do other things..after 15 minutes there is still a steady, yet small stream of oil coming out.

in any case, either way won't hurt.

 

I use Rino Ramp to change oil. After I let the oil drain for 10mins I raise the rear end up with a small floor jackand more oil come out. I let the Vette drain in this prosistion for about 5 mins.

 

Why on earth anyone would think that a 1 or 2 inch difference between the front and rear pads on a 100+ inch wheelbase on a 2 post lift is going to make a safety difference is beyond me. Leaving the geometry issue behind, do you put a level on the bottom of the car while adjusting the pads? I doubt it.

And, the oil will drain down out of the engine just fine if it's not perfectly level; it's designed to do so.

One other thing: when you remove the oil filter some dirty oil that was trapped in some of the oil gallerys will drain down into the pan as well. Check next time and see if you don't start getting another small stream once the air seal is broken on the filter.

Not flaming anyone, but don't like seeing bad info out there either.

Have a good one,
Mike

 

you asked why : because many folks here are on the obsessive-compulsive side

About 99% of the C5s probably have their oil changed on a level basis and that is why GM designed the pan as you describe. Ya know those folks that step over cracks on the sidewalks . . .

 

The lift points on my 2 post are the jack pad locations at the front and rear of the doors. The distance is around 64".
I know. I like to do it my way, it does take the little bit left in the pan out.
That's why I change my oil filter when I remove the plug.
Not taken as a flame. Just telling how I do it. As I said I had the oil pan off last week and had a bird's eye view of the sump system and up into the engine from the bottom. There was also a lot of oil just clinging to the walls that will never come out. Well, a lot is probably a couple of ounces if it's all added together. It's just me being OC.