Oil leak near pressure sending unit
 

about 2 years ago, I did the dreaded TB job and just went to town and replaced EVERYTHING. I had an oil leak that looked like it was the sending unit and replaced it and everything around it. I cleaned everything real nice, change the oil and watched it closely for a while. No drips or leaks that I could see and I forgot about it.

At some point last year, I smelled some burning oil and low and behold, the pan, oil pressure sending unit and drivers side of the engine had a thin coating of oil blown accross it. I'm stuggling to figure out where its coming from as its blown all over the place. Are there any common problems in this area that I should investigate?

On that side of the engine there are half-a-dozen spots oil will leak from...

Cam seal (which will leak behind the cam belt cover)
oil cooler lines (rare)
sending unit (moi common)
oil pan (even moi common)
power steering line/resevior
And, depending on what year you have, it could be the cam carrier itself.

Scott
:cheers:

Oil pump seal on that side too.

:cheers:

Sterling,

I read that on Greg Niochols site... I didn't do that.

As far as the cam and oil pump seals... when I had that whole area apart, they didn't appear to be leaking. That doesn't mean they aren't leaking now. I tried looking fro a picture of the cam and oil pump seal but could only find the oil pump seal. Whats the cam seal look like?

The most common leaker in that area is the pan gasket - and when driving, oil is blown all over those components: BTDT ;) first, check the pan bolts ...

It is really tough to diagnose an oil leak if it has been going on for a while, my sensor leaked and oil ran backwards and forwards along the pan gasket line. Oil is always sitting in that area when at rest so that metal crush where the housing mounts to the block has got to be in good condition.

When the oil cooler lines leak against the block it can also look like the sensor as others have mentioned.

Give the whole area a thorough clean/degrease (the car will thank you for that anyway), go for a good drive to get it nice and hot.

Get underneath and recheck.

Chris

I checked the pan for tightness and it seemed fine. Also, the oil appears up as high as the exhaust manifold and all the way forward to the front of the engine. I had originally thought cam seal but when I got everything apart, it did not appear to be coming from there. At one point, I thought it might have been coming from the distributer, the oil fill cap or even the oil fill tube (but thats on the other side which is relatively clean). I replaced all the lines going to the oil fill area just in case.

I don't think I ever really cured the problem. I think alll the cleaning delayed the onset of any visible signs and with clean oil, any minor film was likley less visible. As the oil aged and darkened, and road grime stucks to it, it now looks like crap.

I have the alternator off now (dead - also replaced when I did the TB job less than 5k miles ago and I think it was a casualty of this leak). You get a nice look into the effected area without the alternator but it would need go back on for a ride then, it limits your view ( catch 22).

I'll likely try the yamalube trick on the sensor housing but I'm trying to asses if its worth doing more while I'm in this far.

BTW, my car doesn't have the oil cooler or lines. Its also defenitley engine oil and not P/S fluid.

Found it... I think. It appears the leak is coming from gasket between the drivers side head and the aluminum housing that the distributer mounts on. This is the housing just behind the cam wheel but the leak in not behind the cam wheel on the cam seal side, its at the other end. It looks like its the joint between that housing and the head??? I tried tightening the mounting bolts but the leak appears to have gotton worst.

I've stripped the front of the engine back down to the timing belt and I will need to pull the timeing pulleys. I'll review the manual but is there anything I should watch for? Would you do both sides and also the timing seals while its apart?

I suspect you are correct! ;) When I did the TB on my '80, the large O-ring seals and the small plug seals ( brown blobs at the end of the pick) were passing , as was the distributor shaft O-ring.
Also check the oil filler gasket.

Garth,

thanks for the pic! A few questions if you don't mind. Whats the deal with the double hex head on the cam bolts? What do the plug seals do? How hard was it to get that whole mess off and did you do cam towers being that far in?

When I found the leak, the oil drip was presenting itself right at the outside bottom corner of where that housing and the head meet. Its tough to tell exactly where it originates (between the 2 surfaces or somwhere above and running down).

- The large hex washer is used to turn the cams without interfering with the cam nose bolt torque setting - remember that at 45deg BTDC, it is save to turn in either direction with the TB off ( and safe at TDC if non-interference).
- The ' brown' plug seals ( almost translucent when new) link to oil passage ways from the heads - see to the bottom inside of the cams in the attached pic. The 5-8 bank feeds the distributor drive, and IIRC, the 1-4 bank feed may be a dead end into the cam gear back cover.
There are cam nose spacers on either side that are sealed by two 1mm thick O-rings, and the standard oil seals on the cam ends. plus the 'plugs' and the 5mm thick O-rings.
It is nothing to pull it apart - and when you do, remove the back ( black plastic) cover as well: only then can you be sure of the oil sources ( there are always more than one !). To reassemble is not a problem if you have the front seals, for there are two keyways and gears, spacers ... to go on the 5-8 cam. My parts were too late, so I lined everything up with a piece of wire and reassembled without disturbing the outer seal - like building a ship in a bottle - but no leaks. ;)
I did not touch the cam towers, as they were well sealed. I had wanted to replace the oil filler gasket (~2x6" deal), but the thermostat housing crossover refused to yield: I tightened the two bolts ( one inside the filler neck), and it's still dry too.

Garth,

thanks a bunch for the help. A picture is worth a thousand words and yours are quite helpful. You gotta love our cars... what started as a simple alternator repair has turned into a fairly involved project and to boot all hell, this is the second time in 5000 miles I've had to undress the front of the engine. I'm getting good at it though.

If memory serves, I tried removing the t-stat housing as well (I polished everything I could get off but mine wouldn't budge either.) Glad to hear your towers were good... I was fearing you would recommend doing those as well being this far in.