97 GTX with injector oil leak (not reservoir or grommet)

[docbda]

All my injector oil leaked out over the winter.

After removing the oil from the bilge and refilling the reservoir with oil, I

1. I pulled the reservoir tank and it was fine (seam that has the reputation for failing was in tact, and oil continuing to leak with oil level below the seam).
2. Reservoir grommet doesn't appear to be leaking (dry on the outside and the hoses aren't slick with oil)
3. Hoses going to and from crank case are not leaking (pulled the pipe to inspect the oil return hose nipple on the crank case)
4. Hose going from res to oil pump not leaking
5. Don't see any oil coming from the pump itself
6. Don't feel any oil around the seam in the crank case
7. Replaced the small lines going from the pump to the injectors. These looked fine, just did it because I had everything apart.

Leaks with the engine off. Engine runs (or did before I removed the carbs and pipe so I could see what I needed to). I marked the reservoir with a sharpee and it leaked about a half inch over two days.

Unless I get a better idea from this forum, I've decided to move forward with this plan:

1. Pinch off the hoses going to the crank case and the hose going to the pump. Wait. If oil level drops, issue has to be the tank or the grommet.
2. If oil level is maintained I'll open hose to the oil pump. Wait. If level drops, the pump or at least something in that direction is leaking.
3. If oil level maintained, then I'll open the hose to the crank case. At that point I'll assume I'm going to lose some oil. Then I'll know the issue is the crank case.

I think that logic makes sense. Kinda wish I had gone this route before I started disassembling things. Oh well, I had the carbs off already to rebuild them.

Love to hear everyone's thoughts.

Blake

 

[mikidymac]

If the oil is leaking into the hull it is either a hose, grommet or tank seam.
If the oil level is dropping with no leaks visible in the hull then it has to be leaking into the crankcase and is either the inner crank seals, rotary shaft seals or oil pump check valves.

 

[docbda]

I definitely have oil visible under the motor that has reaccumulated after I cleaned out the hull and refilled the res. The tank seam is out because the leak continues with the oil level below the seam. The grommet is still an option, although I would think with this large a leak I would be able to feel it on the outside portion of the grommet and the hoses.

I guess pinching off all the hoses will remove a hose/engine connection leak as a variable. If the leak persists with the hoses blocked it's the grommet or a hose/grommet connection.

What's the chance of the crankcase seam leaking? you didn't list that as an option.

Thanks a ton for your reply!

 

[GGuillot]

Ck the cable bracket at the oil pump, the 2 screws may be loose. Put some dry clean rags under the grommet and the oil pump, one of them may be leaking. Recheck those lines for the rotary valve cavity, put rags under them, one of them may be leaking at the fitting.

 

[etemplet]

I replaced the oil lines on a ski recently and had a hell of a time getting them to seal. They product I used was too stiff and not the exact size. It was so so close but no cigar. I ended up buying a more pliable grade of clear hose the exact size. I'd highly recommend buying the OEM hose. I fought this leak a bit. It was a real pain.

If you have a leak that size in the engine internals it would lock up trying to start. It doesn't take much oil to raise the compression enough to overcome the stater ability.

 

[docbda]

Good morning folks,

Thanks to everyone for your input. So far the oil level has not dropped with the lines going to the oil pump and rotary valve cavity pinched off. I'm going to give it another day. Based on what folks are saying I will remove the clamp going to the oil pump first. Sounds like that's the more likely culprit. I'll shop vac out the oil and place clean rags as suggested. Good to hear that the leak is likely not internal based on the facts that I can see the oil in the bottom of the ski and the engine turns over easily.

As far as the hoses themselves, they appear to be in good shape and are pliable. I will look at OEM hoses if I need to replace them as this bit of fun plays itself out.

I'll keep ya posted.

 

[docbda]

Went out this AM and the oil level has dropped in the reservoir with the lines still blocked going to the crankcase and to the oil pump, but not as much as before over two days. Before it dropped half an inch. This time approximately a third of an inch. I guess this means that at the very least the grommet, or a connection to the grommet is leaking. Without thinking, I did put one of my clamps south of the oil filter, so the filter is also an option. Of course, it's possible that I have more than one leak, which would explain why the oil level has not dropped to the same degree as before. Not sure of the physics of this, but the other explanation for the level not dropping as much is less oil in the reservoir = less hydrostatic pressure pushing on the leak (although there is still plenty of oil left in the res).

Today, I will clean out the oil from the bottom of the hull and put the rags down. At least I have a direction to go now. Still not sure how this much oil can leak out of the grommet or hose connections to the grommet and not have oil detectable on those components.