When I start my 1998 Dodge Ram pickup it starts and the oil light is normal then after runs for a few minutes pressure goes down to zero engine shuts off do need new engine?

No, you don't automatically need a new engine. A sudden drop in oil pressure followed by engine shutdown strongly suggests a serious problem, but it's not necessarily a catastrophic engine failure. Several things could cause this:

* Low Oil Level: The most basic and hopefully easiest fix. Check your oil level immediately. If it's low, add oil (the correct type and amount for your engine) and see if the problem resolves. If it is low, find out *why* it's low – a leak is a serious issue.

* Oil Pump Failure: The oil pump is responsible for circulating oil. If it fails, pressure drops to zero. This is a significant repair, but doesn't automatically mean a new engine is needed.

* Clogged Oil Filter: A severely clogged oil filter will restrict oil flow, leading to low pressure. Replace the oil filter (and change the oil while you're at it).

* Worn Engine Bearings: Worn bearings in the engine allow oil to leak past them, reducing pressure. This is a more serious problem and can eventually lead to engine seizure. Repair will involve significant engine work.

* Leaking Oil Cooler: A leak in the oil cooler will cause oil loss and pressure drop.

* Blocked Oil Passage: Something could be blocking an oil passage within the engine. This is less common but a possibility.

* Sensor Failure: Though less likely given the engine shutdown, a faulty oil pressure sensor could give a false reading. This is the cheapest and easiest thing to check, but should be done *after* checking other potential causes.

What you should NOT do:

* Don't start the truck again. Running it with low oil pressure will cause severe engine damage very quickly.

What you SHOULD do:

1. Check the oil level immediately. Add oil if needed, *only if the engine is cool.* Never add oil to a hot engine.

2. Have a mechanic diagnose the problem. This is crucial. They can properly assess the cause of the low oil pressure and recommend the appropriate repair. Ignoring the problem will likely lead to much more expensive repairs or even a completely ruined engine.

Ignoring low oil pressure is extremely risky. Get it checked out promptly by a qualified mechanic to avoid further damage and determine the extent of the repairs needed. The cost of diagnosis is far less than the cost of a new engine or a major engine rebuild.