The problem isn't simply "low oil pressure," but *why* the pressure is low. Common causes in Northstar engines include:
* Worn or failing oil pump: This is a major culprit. The pump might be worn out, have a faulty drive, or have a clogged pickup screen.
* Worn bearings: Low oil pressure is often *a symptom* of already worn crankshaft or connecting rod bearings. The bearings are failing, leading to more pressure drop. This is a serious mechanical problem.
* Clogged oil passages: Sludge buildup in the engine can restrict oil flow. This is less likely in a well-maintained car, but possible.
* Leaking oil cooler: If the oil cooler has a leak, oil bypasses the normal pressure system.
* Faulty oil pressure sending unit/sensor: This is the *least likely* cause of significant pressure loss. A bad sensor will give a false low pressure reading, but the actual pressure might be fine. Have a *mechanical* gauge used to confirm the actual pressure.
* Insufficient oil viscosity: Using oil that's too thin for the operating temperature can result in low pressure.
* Damaged or restricted oil filter: A clogged filter would restrict flow.
What NOT to do: Ignoring the problem will almost certainly lead to a very expensive engine rebuild or replacement. Adding oil thickeners (like STP) is a temporary and often damaging band-aid; it masks the problem and can cause more issues.
What you SHOULD do:
1. Get a second opinion: Find a reputable mechanic specializing in Northstar engines. The Cadillac Northstar is known for some quirks, and experience with this engine is crucial.
2. Have the oil pressure checked with a mechanical gauge: Don't rely on the vehicle's oil pressure sending unit – it could be faulty. A mechanical gauge provides an accurate reading.
3. Investigate the root cause: Once the actual pressure is confirmed (low), the mechanic needs to find *why* it's low. This usually involves further diagnostics, potentially including oil pressure tests at various engine speeds.
4. Address the underlying problem: This might involve replacing the oil pump, bearings, oil cooler, or cleaning clogged passages. This will likely be a significant repair, but much cheaper than a new engine.
In short, low oil pressure in a Northstar is a serious problem that requires professional attention immediately. Don't drive the car until it's fixed. The cost of ignoring it will far outweigh the cost of proper repair.
