oil leaking from back of engine?

Nipper · #1 (**permalink**) 12-13-2006, 02:49 AM

After finally fixing all the small annoying coolant leaks comming from my car, I almost fainted when I noticed a small amount of liquid under my car. It turns out it is engine oil this time. I havn't had a chance to get under my car yet but it seems to be comming from where the exhaust headers bend 90 degrees to meet the exhaust pipe that runs the length of the car. I have circled the area in the picture where I think oil is dripping from. What gets me is that the oil is found about 20 cm from the end of the sump so it must be running along the downpipe and falling onto the ground. Any ideas of where this oil is leaking from?

alfanfl · #2 (**permalink**) 12-13-2006, 04:37 AM

Possibly from the oil pressure sending unit.

Murray · #3 (**permalink**) 12-13-2006, 06:40 AM

Adam unfortunately the two most likely culprits are the rear crankshaft seal and/or the cigarette seals on the rear main bearing cap.Before you go further it's worth checking the bolts that fasten the upper oil sump to the crankcase.The rear ones are very difficult to access because the steering rack and crossmember are in the way but it can be done.You can also look down into the inspection hole on the bellhousing to see if there is oil on the flywheel - another indicator that it's one of the first two sources.

**AR4me** · #4 (**permalink**) 12-13-2006, 10:37 AM

To elaborate on alfanfl's suggestion. The oil pressure sender for the warning light is known for leaking oil through the "housing" with age (I have experienced it myself). At the rear of the engine, towards the firewall you have the two oil pressure senders: for the warning light and for the gauge. The bulky one is for the gauge and the small one is for the warning light. You can access both from the top, although it is tight. Clean the area around the warning light sender well with rags, paper towel..., and watch the area with the engine running. Let it run a little and check if it is still clean. One sign is that you will see oil accummulation in a little cavity (1/2" to 1" deep) right next to the sender.

If you are lucky, a new warnign light sender will solve your leak. If that is not it, well, if it is just a few drops, perhaps living with until it gets worse makes most sense.

Jes

slyalfa · #5 (**permalink**) 12-13-2006, 02:02 PM

I will add wrap a new rag around each sender. sometimes they will spary a fine mist of oil that can not be seen but if a rag is wraped around it it will show its self.
I had this happen with the oil light sender and it looked like the leak was from the other side as the fine mist collected on the right head while the leak was in the left head out the side of the sender.

Nipper · #6 (**permalink**) 12-14-2006, 05:28 AM

thanks for the explanations guys. Does anybody have a picture or diagram of what the oil pressure sender looks like and where it is placed on the engine? I won't get a chance to play around with my car this week because of work. I should also mention that it takes at least a week after I drive the car to see oil on the garage floor, if this means anything? Something else that crossed my mind was when my car was last getting a tune up, the mechanic had the car on the hoist and I noticed oil in the area just behind the sump, most likely it leaked through the gasket. Could it be possible that the sump gasket is worn and leaking enough oil so it drips on the floor. I must stress that it is only one or two drops that I see, not a puddle. I am also using a synthetic oil, more than likely a semi-sythetic oil. I will assume that the oil pressure sender is the culprit untill I get a chance to look at the car. The car has travelled about 77000 kms (47847 miles) if that helps spark any more ideas. Thanks for the help so far.

Murray · #7 (**permalink**) 12-14-2006, 08:07 AM

Adam the sender is at the rear of the "V" between the heads- see attached.It has a single wire going to it.

slyalfa · #8 (**permalink**) 12-14-2006, 11:26 AM

and the light sender is on the head not showen as there is no head.
but it is very close to the center one on the left head facing the firewall

slyalfa · #9 (**permalink**) 12-14-2006, 11:32 AM

here is a pic that shows both

**DaveH** · #10 (**permalink**) 12-14-2006, 12:07 PM

Great pics. Is idiot light sender the one with the black base and single terminal?

slyalfa · #11 (**permalink**) 12-14-2006, 12:38 PM

"Is idiot light sender the one with the black base and single terminal?"
Yes, but they are somtimes white too.

Murray · #12 (**permalink**) 12-14-2006, 02:11 PM

Hey guys you're making me feel left out

My 86 GTV6 2.5L doesn't have the sender on the head ?

new alfa75 owne · #13 (**permalink**) 12-14-2006, 07:38 PM

Hey, sorry, i have no input for your leak, just a leak of my own. Oil appears to be running down both the front and back of the sump, so possibly two leaks. the drops are in line with eachother, a bit to the passenger side. The one at the back seems to be spraying a bit onto the exhaust (which i just discovered has a patch job on it). The car was garaged for about three years and only run monthly before i got it. I havent changed the oil or filter yet. Is it possible for gaskets to harden in that time??. any clues for where to look would be great, im going hunting for the leak on the weekend.
Oh, it only leaks after a drive, not when its just sitting in the garage.
Thanks, Brian

alfanfl · #14 (**permalink**) 12-15-2006, 04:22 AM

New alfa 75

Oil could be coming from the pressure sender and accumulating in the space between the heads and running forward. You could also have a leak from one of the head gaskets, which I believe is what I have.
Deteriorating gaskets and o-rings are probably more the result of age.

Dave

Giorgio68 · #15 (**permalink**) 12-15-2006, 06:25 AM

or it could be the gasket and cigarette seals on the upper oil pan which is a pain in the neck to replace it, to do the right job engine needs to be pulled out because there is no space to work while the engine is in place. If thats the case and the leak is not so bad you should be able to live with it for now.

Giorgio