View Full Version : STS Blowing Out Oil But From WHERE?????

04-07-09, 04:14 PM
I recently purchased my wife a 2000 STS very nice powerful car. We have had it since Christmas and have had no issues. 3 Weeks ago the low oil light came on. Whebn I checked it IT WAS EMPTY. I had to put 5 quarts in it to get the light to go off. Went out to check it last weekend and found it was a quart low again and I guess I did not notice it before but the insulation blanket under the hood was soaked with oil. I could not find any oil on the motor itself as well as no drips underneath. Took the STS into the repair shop and they cannot find ANYTHING WRONG!!!! They went all over it and could not even find any oil drop anywhere. WHERE IS IT COMING FROM???/ Has anyone else ever expeirienced this???/?? Nothing underneath checked oil cap, dip stick and pcv valve all good. THere is literally NO OIL ON ANYHING!!!! Please help if anyone has any expierience with this. My mother in law had the same thing on her Deville a few years ago and they could not find anything on hers either. (Different repair shop).

04-07-09, 05:40 PM
Never heard of that before. Perhaps it was like that when you bought it. The REAL strange thing is that you where so low before the warning message came on. It should warn you when you are 2 qts low and still have 5.5 in the sump.

04-07-09, 06:10 PM
rdpjr, Did you look in the Owners Manual to find out the oil capacity of your Northstar?? Never fill it past halfway up the dipstick hashmark. 7.5 quarts of 5W-30 with filter.

04-07-09, 06:16 PM
It was not like that when I got it. When the light came on I checked it immediatly and there was no oil on the stick. I had to put 5 quarts in it and make it a little over full to get the light off. Since then I took it in to the repair shop and they cannot find anything. I have all of the covers off right now just waiting for something to show itself but there is nothing (1 week since reapir shop had it). No oil anywhere except on the insulation. I saw the same thing on another cadillac forum but the issue was never adressed after the intial posting. My mother in law has a deville with the same 4.6 Northstar and hers did the same thing a few years ago and no issue was ever found. She still drives iit and that was about 2 years ago and it has not done it since. It is a very odd thing to not find any oil on the motor and not have any drips.

Also I did not check the manual but I did not go up past the top of the hash marks I may have been up around 3/4 or a little better and had to to get the light to go off. After that it did go down to the fill mark again within a week and that is when we took it to the shop. As it sits now it is right above the add line and the shop put some in it too.

04-07-09, 10:30 PM
When the light came on I checked it immediatly and there was no oil on the stick. I had to put 5 quarts in it and make it a little over full to get the light off.
Ahh, and there in lies your problem. The message comes on at 2 qts. low. That is the point when the level just drops off the end of the dip stick. If you added 5 qts to that, you where probably about 3 qts overfull. I suspect you may have a faulty oil level indicator. Like Sub said, "Full" is about 1/2 way up the hash marks. MAX is overfull. The only question now is where the excess oil blew out from and I have no answer.

04-08-09, 11:43 AM
Check your oil cooler lines, there are two on the passenger side (least in pre-2000 style engines, most likely the same). There are a couple things, they are metal and plastic lines, the plastic degrades and 'bleeds' but doesn't necessarily rupture, but with enough pressure it can 'squirt', silly I know. Also, there's a plastic quick connect fitting made of plastic in the metal housing that degrades with time and can fail, it'll be on the passenger side of the radiator, side tank. If you still have the lower splash guard in there it could be pooling on that and running off as you drive, and you'd never notice, also, you won't get much of a 'leak' until the system is pressurized at decent engine RPM/load, idling you might get it to drip, but like i said if it's up inderneath the splash guard you'd never see it.

Also, check your serpentine belt as on my Eldo it was right in line with the oil cooler line and when it blew it tossed my belt, I had oil all over the passenger side of the engine, half shafts/suspension, and up onto my hood. I was going to say PCV but since they pull vacuum and not the other way around you'd have to be pressurizing your crank case which I highly doubt as you'd have other problems for sure...


04-08-09, 12:58 PM
Thanks for the input. I will pull the splash guard and look for the pooling. You think the repair shop would have missed it????

04-08-09, 01:17 PM
I have the same oil-loss thing going on with my 2000 STS with about 80K on the clock. Same "low oil" message, took about 5 quarts to get the level back up on the stick. I've been watching it closely for the last 3-4 weeks and it's dropping slowly; I'll definitely check the cooling lines as suggested and look into the sensor.

FYI, I have an oil-soaked hood blanket, too, but that's 'cause I left the filler cap off after changing the oil and it blew all over the engine compartment. The Mrs. was not happy...:Poke: So maybe the oil loss and oily blanket are unrelated.

04-14-09, 01:58 PM
Just got the car back from the repair shop and once again it is low but nothing showing and they cant find anything. This is after driving it for a few days.