massive oil consumption

Volkovich · 08-13-2003, 06:13 PM

I went on a long drive this weekend and got really concerned about my oil consumption. On my way out of town I was tooling along pretty good 80-100mph and I lost 2 quarts of oil in about 100 miles. I filled the oil to the top and took it easy on the way home 60-70mph and only lost about a half quart.

I know I have a pretty good leak where the oil line enters the engine but I was wondering if at full pressure oil would spurt out of that leak that much? According to Wayne Dempsey's 911 rebuild book you should burn about a quart per 1000 miles. More than that is trouble....

If the leak is not the cause would my car even run right if I were burning a quart of oil every 100 miles? At 15mpg that would mean I was burning a 25:1 gas

il ratio. I don't see a ton of smoke coming out the tail pipe.

I am planning waiting to fix the leak this winter (I have to remove the exhaust to get to the loose fitting) so I don't loose what is left of the summer. Is this a bad idea?

Groesbeck Hurricane · 08-13-2003, 06:16 PM

I would think you were running at a lower RPM at the slower speeds? The pressure on the oil line will greatly effect the amount of leakage.

Where is the oil leak? If it is in the lines near the timing chains these should be easy to replace in an evening.

Mike Kast · Mike Kast's Garage

oil return tubes?

Volkovich · 08-13-2003, 06:24 PM

Yes, lower speed from lower rpms. I was driving slower because on the way home I got a ticket. The cop got me when I was leaving a stop sign and shifting from 3 to 4 gear. He clocked me at 75mph. I was lucky he didn't pass me 5-10sec later because I would have been doing 120mph.... The cop asked my, "Why were you accellerating so quickly?" I didn't answer such a stupid question but was thinking of saying "because I can...".

The leak is on the main line that brings the oil to engine. My car is a 1979 911SC. The fittings that needs to be tightened has a mess of epoxy on it from some old jimmy-rig repair. The problem is that you CAN NOT get a wrench on this fitting. Believe me I tried. The only way to get to the fitting is to remove the heat exchangers. I have made myself believe that removing these is going to be a big pain and something that shouldn't be rushed. I have read Tech Articles on this and it sounds like you need to soak, heat, soak, heat cylcle on the nuts so you don't strip them or break your studs. I don't know if I want to tackle that whduring Michigans very short driving season. However, I do know that fixing the leak is the only way of knowing if the oil is leaking or being burnt in the engine.

APKhaos · 08-13-2003, 06:27 PM

Its amazing how much oil you can loose through a thin wall leak - like a fracture in an external hard line. I had a hairline crack in one of the cam tower lines, which spayed a mist of oil everywhere. A lot of it dissipated in the airflow, so there were no large puddles lying around. Even sneakier, the leak only happened at operating pressure - no tell-tale weeping in the garage. Most external oil lines, including the return tubes, are fairly easy to replace.

Groesbeck Hurricane · 08-13-2003, 06:29 PM

If you look at the lines from the back of the car, is this the lower one that goes from the hard oil line on the drivers side of the car to the front cooler? And is the leak on the passenger side connection or the drivers? I can only do mine when I lift and properly support the vehicle.

Bill Douglas · 08-13-2003, 06:36 PM

There is the possibility that you didn't actually loose that much oil. If you have been doing short trips and not heating up the oil much it can contain a lot of water, and a big, full on, blast warms up the oil and burns off the moisture.

Volkovich · 06:42 PM

The leak is on the drivers side near the front of the engine block. The rubber line has a steel portion that screws into the engine block. I think this fitting is lose but can't be sure because it is covered in something that looks like JB Weld.

If you have Wayne's rebuild book it is the fitting in picture 2-30. This is right by the front return tube. (How do you post pictures to this forum?)

[IMG]C:\Documents and Settings\Tim\My Documents\My Pictures\oil leak.jpg[/IMG]

HarryD · 08-13-2003, 06:46 PM

Quote:

Originally posted by Volkovich
The leak is on the drivers side near the front of the engine block. The rubber line has a steel portion that screws into the engine block. I think this fitting is lose but can't be sure because it is covered in something that looks like JB Weld.

If you have Wayne's rebuild book it is the fitting in picture 2-30. This is right by the front return tube. (How do you post pictures to this forum?)

[IMG]C:\Documents and Settings\Tim\My Documents\My Pictures\oil leak.jpg[/IMG]

If you use the IMG button, you need to have a web hosting service where your picture is uploaded. Then enter the url for the hosted picture.

An alternative is to use the "Attach File" that appears below the text window when you post a new message or hit the reply button. There, you can upload a picutre to Wayne's server and have it show up.

Mike Kast · Mike Kast's Garage

click the (post reply) box above to the left of this here quick reply box. Then click (Attach Multiple) and your on your way

Volkovich · 08-13-2003, 06:49 PM

Okay, thanks for the hint. The leak is coming from this location. I thought it was the fitting on the left but now that I see that the oil return tube is right next to it I am not 100% sure.

Bill Douglas · 08-13-2003, 06:53 PM

That's easy.

Volkovich · 08-13-2003, 06:56 PM

I heard return tubes are easy. If you have a suggestion on how to tighten the main oil line without removing the heat exchanger I would love to hear it. I have tried every wrench I have and none will work.

Mike Kast · Mike Kast's Garage

I thought I read somewhere that the heat exchangers have to come down to do the return tubes. Is that correct? and Bill, be careful who you say things like "that's easy" to. In my world, I have found about nothing to be easy. Especially when I'm lying on my back under a car...lol...

Bill Douglas · 08-13-2003, 08:23 PM

Good thinking, sometimes I never know when to shut up. And..., it depends which heat exchanger too.

Mike Kast · Mike Kast's Garage

please don't shut up Bill. You obviously know more than me if its easy for you. I want to learn enough so I can someday forget how stupid I am right now...

Volkovich · 08-14-2003, 04:25 AM

Everyone is talking about the oil return tubes... I haven't heard anyone confirm how difficult it is to tighten the main oil line fitting.

BTW: My car has the pre-1974 exhangers on it if that makes a difference.

Vipergrün · 08-14-2003, 06:45 AM

You *may* be able to get at that fitting with a 36mm crows foot, however, you may be required to remove the HE's to really get on it, especially if you have an epoxy kludge to deal with. I couldn't get anything on it with the stock HE's in place. Removing the HE's is not that bad. PB Blaster, a Mapp torch, slighly tighten nut, then try to remove. If you don't drive your car on the salty, wet roads, you may not have that much corrosion. If you anticipate doing this job, just PB the nuts a few nights in a row.