I have a 1998 Jeep Grand Cherokee with the 318 V8 with about 167,000 kms (100,00 miles). The other day on the highway, I noticed a ticking sound which I interpreted to be valve lifter noise, which seemed to be intermittent - would be apparent for a few minutes, then disappear for a while before returning. At that time I also noticed the oil pressure gauge would go to zero or fluctuate. I immediately pulled over, checked oil level, found it to be OK. The engine otherwise seemed to be operating normally (no loss of power, difficulty starting, roughness, or any such). Took it to the shop who identified and replaced a faulty oil pressure sensor and changed the oil (oil change was significantly overdue).

The engine seems to be operating normally again.

My question: is the pressure sensor used in any way to regulate oil flow in the engine? In other words, could the faulty sensor have caused an oil flow problem resulting in the lifter noise? Was the noise due to overly dirty oil? Is any of this pointing to a possibility of engine damage and/or imminent breakdown?

1 Answer 1


The pressure sensor does not control flow - it just "reads" the pressure to give you a value on the gauge.

The overly dirty (or probably thin) oil may have caused the loss of pressure as the pressure relief valve is designed to work with an viscosity range and if it is too thin may not keep the minimum pressure required.

As to damage or possible breakdown - it may have reduced the lifetime but difficult to measure or predict. Even if you strip the engine - at this life / use it will show wear anyway.

If it is now running fine then respect the oil and filter changes and enjoy it.

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