Oil/fluid leak/drip... help locating source

[Jonathan]

28645

If you can see where the red arrow on this is pointing to, it's where I seem to have a small drip/leak of oil narrowed down to. I've been steadily cleaning up underneath my car (the photo isn't my car, just a suitable photo I found online), and it seems the only place remaining where it drips a small amount over time from is right at that little knob/extending part that comes down a bit.

I know it also ends up being the lowest point and could be where any oil from above is going to collect, but looking above this point on the sides, it just doesn't look wet or obvious. Is this right next to the seam where the engine mates to the transmission? Is this area a common spot for leaks? Anything I can put a torque wrench on and tighten up?

[Michael]

If it's oil I would immediately think rear main seal.

are you sure it's oil?

[D Knight]

I agree. If it's oil I'd say rear main. If it's trans fluid possibly the input shaft seal.


-D Knight-

[djdogbone]

Check the cam seals behind the AC pully

[NightFlyer]

Check the axle output shaft lip seals in the transaxle housing. When the driver's side was leaky on my car, it would run down the housing and collect at roughly that point (it was actually at the drain plug, which is a protruded square on a manual car, but on an automatic, it's an intruded square) until there was enough to drip onto the floor.

Even with an auto trans, the final drive still uses standard gear oil, and thus any leak from it will appear like regular engine oil on the floor.

The severity of the temperature swings experienced over the last winter appears to have wreaked havoc with these seals for many.

If it ends up being that, I put together a step-by-step 'how to,' if you're interested (adjust for differences if you have an auto trans):

http://www.dmctoday.com/showthread.php?710-Change-Transaxle-Output-Shaft-Lip-Seals

[Jonathan]

"Are you sure it's oil?"

Good point. Yesterday I put down a brand new leak monitoring and management system (AKA a fresh piece of cardboard with some new white paper towel taped to it). I think what is on the paper towel after 24 hours is oil. There have been times where I'd move the car and then have a look at what was left on the garage floor and when wiping it up with a paper towel, it sometimes had enough of an orange hue to it that I thought possibly it was the bright red ATF mixing with the engine oil or gear oil.

I rarely find what is clearly red ATF, and when that happened two seasons ago, there was a flood out the back as my dipstick tube seal went.

So I'm about 90+% sure it is oil.

Like you said, could be the engine oil (20W50 for me) or gear oil (80W90) from the rear axle.

I'll check those things you mentioned. About three seasons ago I had both rear axles out and all the boots replaced as well as the seals and hardware at the transmission. It hasn't been a problem to my knowledge since, but it could be again. Nothing saying it couldn't anyway.

Is rear main seal = axle seals? (or the point where the transmission joins with the engine?)

EDIT: This? http://store.delorean.com/p-6074-sealing-ring-rear-main-seal.aspx

I'll have to do some research to make sure I know what was meant by input shaft seal as well as the cam seals behind the A/C pulley. I don't have an A/C belt on at the moment as I noticed one of my tensioner bracket pulleys was wobbling and chewed a belt, but I don't think that is related.

One thought I guess though, with any of these you've mentioned, none of them are just "tighten up the bolts" fixes, right? When you look at the underside of the transmission, there are a whole mess of bolts, but I think now that you mention wondering if it was ATF or not might say it isn't those as it wouldn't be oil if any of that was not torqued right.

[NightFlyer]

"Are you sure it's oil?"

Good point. Yesterday I put down a brand new leak monitoring and management system (AKA a fresh piece of cardboard with some new white paper towel taped to it). I think what is on the paper towel after 24 hours is oil. There have been times where I'd move the car and then have a look at what was left on the garage floor and when wiping it up with a paper towel, it sometimes had enough of an orange hue to it that I thought possibly it was the bright red ATF mixing with the engine oil or gear oil.

I rarely find what is clearly red ATF, and when that happened two seasons ago, there was a flood out the back as my dipstick tube seal went.

So I'm about 90+% sure it is oil.

Like you said, could be the engine oil (20W50 for me) or gear oil (80W90) from the rear axle.

I'll check those things you mentioned. About three seasons ago I had both rear axles out and all the boots replaced as well as the seals and hardware at the transmission. It hasn't been a problem to my knowledge since, but it could be again. Nothing saying it couldn't anyway.

Is rear main seal = axle seals? (or the point where the transmission joins with the engine?)

EDIT: This? http://store.delorean.com/p-6074-sealing-ring-rear-main-seal.aspx

I'll have to do some research to make sure I know what was meant by input shaft seal as well as the cam seals behind the A/C pulley. I don't have an A/C belt on at the moment as I noticed one of my tensioner bracket pulleys was wobbling and chewed a belt, but I don't think that is related.

One thought I guess though, with any of these you've mentioned, none of them are just "tighten up the bolts" fixes, right? When you look at the underside of the transmission, there are a whole mess of bolts, but I think now that you mention wondering if it was ATF or not might say it isn't those as it wouldn't be oil if any of that was not torqued right.

Rear main seal = engine block
Input shaft seal = transaxle housing (on end with mating flange to engine block)
Axle lip seals = transaxle housing (sides)

I highly doubt that you'd be getting a leak there from anything to do with the A/C compressor (either the bearing seals for the tension idlers/guides or the compressor's shaft/bearing seal).

Correct - none are simple 'tighten up the bolt' fixes, but rather PIA fixes.

If you're leaking ATF, which would definitely leave a visible trail to the the point of accumulation and drip off that you've identified, you can tighten the pan bolts up, but as there's a gasket there, you don't want to go much beyond the torque spec for such bolts, otherwise you'll compromise the gasket. Thus if messing with the trans pan at all, I'd recommend removal and replacement of the gasket at a minimum.

As far as re-occurring leaks from the axle lip seals is concerned, it's very possible, even if you just changed them out. Especially on the driver's side (at least on manual cars anyway). It's possible that you may need to center the axle output shaft and tighten the adjusting nut a few degrees on one of the sides. If that's the case, proceed with caution and don't over-tighten, as doing so will cause premature wear of the final drive bearings (and possibly worse).

Best luck :thumbup:

[DMCMW Dave]

I agree. If it's oil I'd say rear main. If it's trans fluid possibly the input shaft seal.


-D Knight-

Rear main leaks typically make a mess closer to the engine, and on the frame. If you see oil where you are pointing it's more commonly an axle seal.

[Flicky]

I am hunting a strange drop near that area too. I'm considering switching to Brad Penn Racing engine oil so it will be green (old Kendall).

[Chris4099]

When I had a leak, I simply added some dye I picked up at a local Napa to my engine oil. After some driving, I got out a UV light and the bottom of my engine and transmission started glowing! Pretty much confirmed I had a rear main seal go out. So if you want to easily rule out engine oil, the dye is a good way to go. But I do agree with Dave based on the leak location, it's probably an axle seal.




I highly doubt that you'd be getting a leak there from anything to do with the A/C compressor (either the bearing seals for the tension idlers/guides or the compressor's shaft/bearing seal).

Correct - none are simple 'tighten up the bolt' fixes, but rather PIA fixes.


I knew a local owner that had a leak down the front of the engine and it was caused by loose idle bracket bolts. Tightened them up and it went away. Has to do with the cam cover behind it. There's on o-ring there that keeps the oil in. If the bracket is loose, oil can get past. I've also had to replace that o-ring on my own D to fix a leak up front. That was one of those 3 hands needed in a tight space jobs! Fortunately for the PO, not something to worry about with his leak.

[DMCMW Dave]

I knew a local owner that had a leak down the front of the engine and it was caused by loose idle bracket bolts. Tightened them up and it went away. Has to do with the cam cover behind it. There's on o-ring there that keeps the oil in. If the bracket is loose, oil can get past. I've also had to replace that o-ring on my own D to fix a leak up front. That was one of those 3 hands needed in a tight space jobs! Fortunately for the PO, not something to worry about with his leak.

We see cars in here all the time where that O-ring is like a rock (i.e. dried out from heat), covered with RTV, and leaking. Or the o-ring is missing. They leak like crazy, lots of oil sloshing around there.

[David T]

We see cars in here all the time where that O-ring is like a rock (i.e. dried out from heat), covered with RTV, and leaking. Or the o-ring is missing. They leak like crazy, lots of oil sloshing around there.

That "O" ring is usually replaced whenever you do the idler bearings. Most venders supply one with the 2 bearings as a kind of a "kit" knowing they get hard and leak by the time you need idler bearings. Just like when you order an oil filter you also get the seal for the drain plug. The other common leak is the oil light sender on the rear, left side of the motor. Looks like a leaky pan gasket but the OE pan gaskets don't leak!

Question; How do you know when it is time to check the oil on a British car?

Answer; When it STOPS LEAKING!

[Rich_NYS]

Jonathan,

I changed my axle lip-seal on the drivers' side a few months ago, it wasn't too bad of a job. When mine was leaking I also had fluid collect in that spot you pointed out.

[NightFlyer]

There's no question that a leak can develop from the idler's because of a failed o-ring - it definitely can and does occur.

However, I don't think that such a leak would pool at the transaxle nub and drip to the floor from that location, and especially not without leaving a clearly visible trail.

Based on the location that Jonathan identified, it's mostly likely a transaxle lip seal.

[DMC5180]

If your trying to figure out which fluid the leak is, do a smell test.

Engine oil, gear oil and ATF have distinctly different odors.

[jawn101]

Rear main leaks typically make a mess closer to the engine, and on the frame. If you see oil where you are pointing it's more commonly an axle seal.

Interesting. I pulled my engine three times to replace the rear main because of drips in that exact spot. Did the axle seals a while back and never really considered those might be the cause of the drip here. Hmm....

But, come to think of it, I have Red Line MTL in the trans which is very very different from the engine oil. I am gonna get under the car this weekend and see if I can tell which fluid it is. Lip (axle) seals are a hell of a lot easier to re-do than that rear main...