First Drive Today

[Corsair613]

First (brief) drive today, around the block a few times. I think I'm going to have to wear my racing shoes, as my regular sneakers are too wide by far.

Minor coolant leak at the radiator thermo-switch was resolved by some extra tightening, as was a small fuel leak at one of the filter connections.

We've got a perplexing oil leak that is most definitely not resolved. When idling the engine in the garage, oil was pooling at the front of the intake valley plate. After driving the car, the oil was dripping slowly out the back of the intake valley plate onto the top of the gearbox casting. Since the engine (and car) sit slightly nose down, we figure that the leak is likely at the back - running downhill at rest and backwards under acceleration.

Possibly related issues: the oil pressure gauge is still pegged high. Could be a gauge problem or an actual high-pressure problem. If the latter, it could be forcing oil out somewhere that wouldn't present any trouble at normal pressure. I need to get an alternate pressure gauge to confirm the reading. The yellow light on the dash, which was going out properly the first few times we started the car, is now on solid and not going out, which also makes me think that the oil pressure is actually high.

Ugh. Just in time for everyone to take off for the holiday weekend, so not much progress is likely until next week. Ugh.

I'm open to any and all ideas…

Ken

[Steve_D]

Sticking pressure relief valve.

Steve

[Corsair613]

Steve_D said:

Sticking pressure relief valve.

Steve

OK, I'll bite. Where is it located on my LS7 and how do I unstick it?

I bought an oil pressure test gauge tonight and will check the system tomorrow. Once I know what the pressure really is, I can begin to nail down a solution. That said, your idea sounds very plausible…

Ken

[F.C.]

Corsair613 said:

First (brief)
The yellow light on the dash, which was going out properly the first few times we started the car, is now on solid and not going out, which also makes me think that the oil pressure is actually high.

Ken

I thought yellow light was ignition, red light oil?
Surely if you have high pressure the light would go out and not remain.
Are you sure it is the oil pressure light and not a separate issue with the ignition/charging circuit?

[Steve_D]

Red would normally be ignition.

If the oil light is staying on then the switch has possibly been broken by the high pressure.

Steve

[Corsair613]

My understanding from the factory is that the red light is ignition/charging and the yellow light is oil pressure (too low/high). If you think of it, each light is adjacent to the relevant gauge.

So, which switch might've been broken by the high pressure? Are you referring to the oil pressure sender, itself?

I'll be checking the system pressure this morning with a test gauge I bought last night and will report back.

Ken

[F.C.]

Steve_D said:

Red would normally be ignition.

If the oil light is staying on then the switch has possibly been broken by the high pressure.

Steve

My addled brain!

[Corsair613]

Some updates:

- The oil leak has been traced to an Allen-headed plug on the rear of the intake valley plate under the throttle body. Gail is sending me a special short Allen wrench so I can crank that plug tighter (before applying silicone sealant) without removing the intake. I won't run the engine again until that's squared away, probably early next week before the mail arrives after the holiday weekend.

- I swapped the wire positions on the oil pressure sender and it now appears to be functioning normally (and the yellow light is out). So, as of now, I don't believe that I ever had an unusually high oil pressure situation. The sender, itself, also seems to be OK.

Should there be a constant flow of returned oil into the dry sump tank? Looking through the filler cap with the engine running, I don't see any oil being returned. Is it possible that my return line is plugged somehow? I can't imagine how, but stranger things have happened on this project…

Ken

Edited by Corsair613 on Wednesday 25th November 21:50

[Storer]

Ken
If you wish to avoid waiting for the allen key from Gail you could make one.
Take the correct size allen and with a cutting disc in an angle grinder, slowly to avoid making it too hot, cut the key to size. Simples.

Less than 5 mins and you can start her again.


Paul

[macgtech]

Corsair613 said:

Should there be a constant flow of returned oil into the dry sump tank? Looking through the filler cap with the engine running, I don't see any oil being returned. Is it possible that my return line is plugged somehow? I can't imagine how, but stranger things have happened on this project…

Edited by Corsair613 on Wednesday 25th November 21:50

Yes there should be, but you probably won't see it due to the design of the top of the dry sump tank. It has a baffle and pipe to direct the flow round the side to 'defroth' the oil. If the return was plugged and not refilling the tank you would run out of oil in a few seconds

[Corsair613]

macgtech said:

Corsair613 said:

Should there be a constant flow of returned oil into the dry sump tank? Looking through the filler cap with the engine running, I don't see any oil being returned. Is it possible that my return line is plugged somehow? I can't imagine how, but stranger things have happened on this project…

Edited by Corsair613 on Wednesday 25th November 21:50

Yes there should be, but you probably won't see it due to the design of the top of the dry sump tank. It has a baffle and pipe to direct the flow round the side to 'defroth' the oil. If the return was plugged and not refilling the tank you would run out of oil in a few seconds

Good info, thanks. What oil level should I be able to see in the tank? Just above the baffle plate? Any difference in apparent level with the engine running?

Ken