Time to give up?

[gl1674]

After a couple of month of not sitting my engine developed a couple of problems:
1. Oil pressure light comes on at idle. It only starts doing it after warm-up (~10 minutes of driving) and it stops coming on after ~40 minutes of driving. I can understand why pressure is higher with cold oil, but why pressure gets higher after 30-40 miles of highway driving is beyond me.

Anybody cares to provide an explanation?

The oil pressure switch is an aftermarket one (Warner), I don't know exact pressure it comes on. The factory one is supposed to be 2psi, but that seem to be an awfully low pressure. Besides the aftermarket switch worked fine for 6+ months.

I've measured the oil pressure - it is about 8-10psi at idle (hard to tell with my gauge) and hits it's upper limit of 85psi at ~2400 RPM. The idle pressure is a bit low, the spec is 14psi. The engine has 170k on it, oil has 1k on it.

There are no abnormal noises from the engine - it sounds just fine.

2. Coolant started overflowing from the expansion bottle. Temp gauge is steady, never overheated. I think I could see occasional stream of air bubbles coming through the expansion bottle, but it's not steady enough to say for sure it is a leak from cylinders.

The engine had a long history of coolant loss to oil, even had head gaskets replaced 50k miles ago (with no noticeable effect), but pushing coolant out of expansion bottle is something new it developed after a couple of month of sitting in garage.

I did do a cylinder air leakage test, mostly out of curiosity to see if the engine is worth any repair effort. None of the cylinders visibly leaked air to coolant. The leakage rate results are:
Cyl 1 - 18%
Cyl 2 - 15%
Cyl 3 - 16%
Cyl 4 - 12%
Cyl 5 - 12%
Cyl 6 - 15%
That's cold engine with 170k on it. I'd be interested to compare it with a low-mileage engine.

So my choices seem to be
1. Get new oil, new oil pump, new O.E. pressure switch, new head gaskets. Lots of work with uncertain outcome.

2. Get new used engine with new seals, oil pump, pressure switch etc. Even more work, fair bit of money with also uncertain outcome.

3. Make a tax deductable contribution to charity... No work, certain outcome.