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Discussion Starter #1
Over the weekend I changed the oil in my 95,000 mile N* sitting in a 1998 El Dorado. After draining the oil from the pan, changing the oil filter, plugging the pan and refilling the oil, it took ~20 min for the added oil to completely reach the pan and display full on the dipstick.

This morning, after a 30min drive, I turned off the car and let it sit for 15min, then checked the oil... 3qt. I checked again after another 15min and the oil was showing full on the dipstick.

It seems as though there is a clog somewhere, but where and are there any remedies for this that don't involve a mechanic? I have performed a few WOTs, hoping this would clear out the clog, but don't want to continue this if the engine is not getting enough oil.

Thanks in advance.
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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Ooyyyy I'm not positive but I think I've heard of the oil returns in the N* being small and subject to clogging. What weight oil do you use, how long have you owned the car?

My quick answer is when the car is a qt low put in a qt of Marvel Mystery Oil. Run it for a week or so and see if it improves. WOT will NOT clear out oil return lines. They work on gravity and there is no pressure involved.

Maybe someone will chime in with a better solution that that will probably work.
 

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Discussion Starter #3
I've had the car ~6 months and got it with 87k miles. I currently have Castrol 10w-30 high mileage in there. I cleaned out the Throttle Body a month or so after I got the car and it has been running great. Just happened to notice this slow returning oil issue.
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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Sounds like someone either never changed the oil or ran way to thick of an oil. I think 10W-30 is correct for that vintage
 

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Discussion Starter #5
The car had balding tires when I got it, so I wouldn't put it past the previous owner to neglect oil changes. Mechanic buddy checked out/picked up the car for me... I probably would have avoided it if I was aware of the bald tires.

After some forum searching, I've seen the general consensus is to leave well enough alone when it comes to neglected oil changes. Would WOTs do any damage in the current condition? Ideally, I'd like to get another 50k miles out of this car :)
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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Well if the oil isn't being returned to the pan fast enough the low oil level warning should come on.

If you're running at hi RPM's and you run the oil sump dry you could do damage. I would seriously try the Marvel Mystery Oil.

Contrary to what other say it's good stuff and it can't hurt anything. Use it as recommended, drive for a week or so and change the oil again.

See if that helps the problem. Keep us posted.

The car had balding tires when I got it, so I wouldn't put it past the previous owner to neglect oil changes. Mechanic buddy checked out/picked up the car for me... I probably would have avoided it if I was aware of the bald tires.

After some forum searching, I've seen the general consensus is to leave well enough alone when it comes to neglected oil changes. Would WOTs do any damage in the current condition? Ideally, I'd like to get another 50k miles out of this car :)
 

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White Diamond '03 DHS (with DTS floor shift)
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Definitely sounds like a drain back problem. I would do what Code suggests. Add some MMO and avoid WOT till you get it cleared up.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:eek: Ranger, Codewize, Dkozloski, chime in here if I'm off base.......Your engine has the oil fill cap on the top of the timing chain case, correct? Next time you drive for a while, leave the engine running and pop the hood and carefully pull the oil fill cap. With a good flashlight, look down into the chain case. If there's visible oil frothing around in there, you have a drainback problem. Someone, AJxtc maybe, will see this and offer some insight into how oil drains to the pan from the chaincase.......I have no idea as to how much oil the cam valleys will hold, bur there has to be some drain system there, too.....Hopefully, as you drive the car and exercise the oiling system (more than it has been) the problem will gradually clear up. Curious that you don't get low oil/pressure alarms when this happens.....
 

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Discussion Starter #9
The only feedback I get is 80-85% of the time starting the car the DIC reads "Check Oil Level," so I get out and check it most of the time and the pan level is just under the "FULL" marker.

I've driven at least 60 miles most days for a little more than 3 months. Will check for frothing on the way home from work.
 

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2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
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Drainback? Good God, man, the drainback is the chain case, and it's about 2x8"; you could throw a brick thru there. The head (camside) is sloped towards the chaincase, so there's no pooling.
 

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The Northstar Tuner
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Has it had the lower Case Halves resealed?
TSB to reseal. If not followed you can plug the oil drain back tubes in the block.
 

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Discussion Starter #13 (Edited)
As far as I know the lower case halves have not been resealed.

If the drain back tubes in the block are clogged, what would unclogging them entail? Using MMO, as suggested above?

Picking up the TSB info after work. Is it something a novice would be able to do?

As if the barrage of questions didn't clue in the whole novice thing.
 

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Discussion Starter #14
When I popped the cap off I didn't see anything out of the ordinary. It's actually really clean in there. The TSB is 14 pages of pull the engine out of the car, so I'll leave that as a last resort.

Going to try the MMO and see how that works out. Oddly enough, when checking the oil level 5min after parking the car, the dipstick showed the qt before MAX missing.

In case this is of any relevance, there is a thin "film" of oil on the bottom of the pan, under the car. Not enough oil to reach the ground under the car, but enough that it's noticeable when crawling around under there.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:confused: You may have one of the N*'s that wants to run a half quart low. No sweat. If there are no real droplets of oil on the pan or surrounding parts, that's not enough seepage to worry about. But now the dipstick is only 1 quart down after 5 minutes engine off? Something's changed since yesterday..........1 quart = the bottom of the hashmark on the dipstick.....
 

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Discussion Starter #16
Temps have been the same since I got it, 198-206F with 80F outside temp the past two days. I did notice a VERY light amount of smoke when I opened the cap. From time to time I do notice a slight oil burning smell after parking the car and walking past the hood.

I think part of it is I like this '98 so much I want it to run like it's off the lot. :)
 

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White Diamond '03 DHS (with DTS floor shift)
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Something is just not sitting right with me. I recall the Guru once mentioning just how much oil the Northstar pumps at WOT. While the exact number escapes me, it was a LOT, and thus it has to drain back a LOT real fast so as not to oil starve. I cannot imagine todays oils getting so sludged up as to clog those drains, unless the oil has NEVER been changed. If that where the case, the upper heads and cam area would most likely look like pudding and I suspect you'd be having lubrication problems by now. Is it possible that you are misreading the stick? Take a reading before you start the engine and again after shut down. How close are the two readings?
 

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Discussion Starter #18
It is the red tipped stick, which is a pain to read at times, but I'll upload a few pics in the morning; pre and post start, as well as a pic of inside the cap to see if that helps shed any light.
 

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Discussion Starter #19
'x' marks the spot :)

This morning before starting the car, oil at max
<ADD| | | | x|MAX|----------------------------


After 30 miles, I parked with the car still running
<ADD|x | | | |MAX|----------------------------


After waiting 10 minutes
<ADD| | | x| |MAX|----------------------------


I was unable to get a good shot of the stick with the point and shoot canon cam, but the inside of the cap and under the car turned out. Again, there has never been oil spots on the ground under the car.

BIG IMAGES

 

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It certainly sounds like a block drain is plugged somewhere. But that'd be a lot of pluggage going on for it to retain that much oil.

Where is the oil reading DIRECTLY after you turn it off? You say it's low with the car still running (should be), but then your other check is after 10 minutes. What about 30 seconds after turning it off?
 
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