accidently added used 80w90 oil to the engine oil!!! arrrgggghhhh!!!!

85carrera · 11-01-2011, 11:20 AM

haha...so apparently i need to start labeling my containers properly. ugh. about 6 months ago i guess i put fresh but used transmission oil from my 69 vw in a 20w50 container.

so today i went to put in some more 20w50 only to notice it was transmission fluid coming out. i probably put in maybe a quarter of quart then cursed loudly and turned the car off. what do you guys think are my options? should I just drain it? replace the filter, and re-fill with _proper_ 20w50? :-)

thanks in advance

redstrosekNic · redstrosekNic's Garage

Change the oil and filter ASAP. Wasn't your oil pressure crazy high?

Joe Bob · Joe Bob's Garage

Some of the anal guys would say, change the oil......I wouldn't worry about it....but it isn't MY engine.

Rot 911 · 11-01-2011, 11:29 AM

Quarter of a quart? I wouldn't worry about it.

ivangene · 11-01-2011, 11:31 AM

I would change the oil a little earlier than its "due date" but would not rush out and stop the train by standing on the tracks...I doubt it will have any effect being so tiny of amount....

dshepp806 · dshepp806's Garage

Change it,..then change it again after 300 miles.....

WOW!

Doyle

Caferacer · 11-01-2011, 11:41 AM

Is there an LSD additive in your tranny oil and would this make a difference to those recommending no change?

M.D. Holloway · 11-01-2011, 11:42 AM

Some guys I know actually add about a qt of gear oil to their engine crank - old diesel engines. They swear it lubes the cams better. I would think it would gum up on the rings but they swear by it. Aside from monkeying up the viscosity a bit, I don't think you have too much to worry about. My guess is you used a mineral based tranny oil and a mineral based engine oil? If so, I don't think I would stress over it. If it was sunthetic you may have some additive iddues but it won't hand granade on you - just won't protect like it should...

redstrosekNic · redstrosekNic's Garage

I interpreted the original post as he filled the total amount with gear oil. If it was only 1/4 of a quart, I would still change it, but I wouldn't worry about damage.

RSTarga · 11-01-2011, 12:13 PM

No worse than a can of STP

ivangene · 11-01-2011, 12:17 PM

since we are sharing the odd stuff...I have heard of old timers putting a QT of diesel FUEL in the oil of old cars to clean them up before an oil change...run them a day or two....

I guess knowing what "Fresh Used" oil is...Transmission oil (red) or 80/90W gear oil would help....if 1/4 qt of gear oil i see no harm....again, change sooner than later but IMO no panic...

I think you have to change it though now because there are enough that say to change it that if you dont it will haunt you....so just swap it out

mholbrook38 · mholbrook38's Garage

I have done the quart of diesel in an engine just prior to an oil change.....but not on a Porsche. I've done it on some old 100k+ cars that I bought to clean up and turn over. I didn't drive it like that though. Warmed up to temp and idled in the driveway for about 15 minutes or so. Really helps clean them out.

Personally, I would not worry about a 1/4 quart of trans/diff oil into the sump of a car that uses around 10 quarts for an oil change.

DanielDudley · 11-01-2011, 01:39 PM

Probably anything bad sunk to the bottom a long time ago.

85carrera · 11-01-2011, 01:50 PM

cool thanks for all the input guys! It was due for an oil change anyway so i just went ahead and drained it. but ya it was mineral transmission oil 80w90, used but only for like 1,000 miles.

M.D. Holloway · 11-01-2011, 01:59 PM

no biggy but don't put any diesel fuel in it! That will tear up your seals and add to bearing and cam wear...

DRACO A5OG · DRACO A5OG's Garage

I would change it, but I am OCD. would be up all night thinking about. Sorry, it's just me.

Hugh R · 11-01-2011, 04:17 PM

Once as a kid on my paper route my Honda 90 ran out of gas, it was winter and I grabbed a jerry can from the garage and filled the gas tank while I had my ski mask on, about a mile later it started running like crap. I open the gas cap and smelled diesel.

Gustyones · Gustyones's Garage

Why risk it? I'd change it asap. Do a cost comparison...

RichardM912 · 11-01-2011, 05:53 PM

You have already made the decision and drained the engine but to add a couple of points.

First, the viscosity was not an issue. An SAE50 engine oil and an SAE90 gear oil have very similar viscosities, of the order of 18 cSt at 100C. There are two separate SAE viscosity classifications (J300 for engine oils, J306 for gear oils).

The important issue was the gear performance level of the gear oil. If it was GL-4 or GL-3 - suitable for most manual gear boxes - it would not be any real risk. If it was GL-5 - full EP, suitable for final drives with offset hypoid gears - it could be corrosive to bearings. Safest to change out that sort of contamination. FM is not an issue.

Noah930 · Noah930's Garage

Quote:

Originally Posted by RichardM912

An SAE50 engine oil and an SAE90 gear oil have very similar viscosities, of the order of 18 cSt at 100C. There are two separate SAE viscosity classifications (J300 for engine oils, J306 for gear oils).

Wow, really? Not being sarcastic--I am truly surprised. When I poured Swepco into my transmission a couple months ago, that stuff was so thick, little strings of fluid (think melted cheese from a pizza) would trail off from the bottle mouth when I stopped pouring. That's gotta be way more viscous than regular motor oil, I thought.

As an aside, where do you guys dispose of used gear oil? The local auto parts stores won't take it (citing its blue color). The local lube shops (Jiffy Lube/EZ Lube) won't take it.