Engine oil sucked out of engine in to auto transmission?


#1

A few days ago my son called me and told me the car wouldn’t stay running. He was able to move it out of traffic into a hardware store parking lot. When I got there, there was no oil in the engine. He said the oil light came on a little while earlier. I filled the engine backup with oil and drove it home about 10 miles. My wife followed me along the way in case It broke down again. There was no smoke, and I had let it run a few minutes before we got on our way. It was not leaking. As I arrived home the oil light began blinking or flickering. I parked it and checked the oil. It was almost completely dry.
A couple of days later I was asking a fiend of mine about it. He told me to check for a vacuum hose leak and for engine oil in the transmission. Well, I’ll be danged. I found both. He said he as seen this happen where the vacuum hose breaks and it suck all the engine oil into the transmission. Is this even possible or is there another explanation?
The vehicle is a 2002 Kia Sportage 4 cylinder auto transmission rear wheel drive.


#2

There is supposed to be a vacuum diaphragm between the tranny and engine. If it ruptures oil can get sucked into the tranny.


#3

I would guess that it’s possible. Years ago…the transmission vacuum modulator valve could go bad internally (ruptured rubber diaphragm) and the transmission fluid could get sucked into the engine and burned. It didn’t take long for you to get a smoking engine and the transmission shifted erratically. It really looked bad at first but a new modulator valve would clear everything up.


#4

missleman Thank you. I was remembering exactly what you described concerning small amounts of ATF being sucked into the engine and burned. My question regarding the OP’s problem is how did 9 quarts of engine oil get sucked into the A/T? The shift modulator valve you describe had a vacuum line that ran to the intake manifold which explains how ATF could wind up as exhaust smoke. What is the vacuum source in the A/T that would suck all of the oil out of the engine. Also where did the greedy transmission store it? I’m sorry. I’m a bit confused.


#5

@mitandmin, please let us know how this “shakes out.” I can make no sense of it.


#6

@sgtrock21 … I’m confused as well. The only concrete explanation would be that the oil was added directly to the transmission. I’m not saying that was the way it happened but it’s the only explanation that makes sense right now.


#7

Personally, I’m having an impossible time buying into any of what you were told happening and have to think you were misinformed.

One thing is pretty much certain; the engine is damaged. The only question is the degree of the damage. It’s not a vehicle I’d go far from home with.


#8

I’m thinking we may have to hire a Medium who can contact Andy Rooney for “the rest of the story”.


#9

maybe he can find paul Harvey while he s out there…


#10

missleman As usual I think you are headed in the right direction and I will further speculate. Did the Son perform an oil and filter change correctly draining the crankcase then add the new oil to the transmission? It has happened before. Did Father task Son with replacing the missing oil? About the only explanation I can think of. Did the vacuum hose leak that was discovered have anything to do with the transmission? Oil light on twice. Crankcase dry twice. A/T full of engine oil. I don’t have much hope for the poor 2002 KIA Sportage. I checked my 2010 KIA Forte SX 2.4L I4. The oil filler cap would be very hard to miss and is marked. My Kia is M/T so I have no information on what the A/T filler tube looks like.


#11

Does this car have a combination oil/trans cooler? There may be a break within the cooler allowing engine oil to be pumped into the trans cooler line. Other than that, I’m stumped.


#12

Yeah, I can’t imagine a common point between the two except where the crankshaft meets the torque converter. And I can’t imagine a leak there that would fill the transmission and not just spill engine oil all over the ground.

Also, losing at least 4-5 quarts of oil that fast is one heck of a leak, plus if the transmission got that full of oil (twice), I’d expect it to be coming out of the transmission vent and the transmission not working right at that point.

So I think we all need more information here. I have seen a bad oil filter gasket and a bad oil sender both leak oil that fast, but you end up leaving a trail of oil behind you. And is it possible that the transmission fluid has never been changed, so it just LOOKS like engine oil? Can the OP comment on how he determined that the missing engine oil was in the transmission and whether there was any sign of an external leak?


#13

If a transmission is over filled with ATF it will not function properly if at all and if over filled with engine oil for any length of time failure is somewhat certain.

I can’t think of any link between the engine’s pressurized oiling system and the transmission. Hopefully when the mystery is solved the OP will fill us in.


#14

I’m afraid if the OP discovers engine oil was poured into the transmission twice they will be to embarrassed to return.


#15

I hesitate to mention this, since this discussion is already strangely complicated enough, but I had a Harley Sportster that kept filling the trans with motor oil back in the '70s. Totally different engine/trans configuration obviously, but oh well, there it is.


#16

About that Harley. Was the sump pump failing?


#17

There is no vacuum in the transmission to suck oil …When a vacuum modulator fails, the oil moves the other way, from the transmission into the engine…So, as Knuckles speculated, does the engine have an engine oil cooler?


#18

Rod Knox
About that Harley. Was the sump pump failing?

I don’t know. I was 19 years old and had it repaired by the dealer. The bill wasn’t very high, so it musn’t have been anything serious. I guess it was a dry sump, low pressure system.


#19

More than likely a breather problem with the Harley. Sportsters are unit construction bikes unlike the older Harley Big Twins and 45 cubic inch flatheads.
Unit construction meaning the crankcase, primary chaincase, and transmission case is one unit.

Back in the 60s Triumph and other British bikes went to a similar setup.