confusing engine leak

My 01 2.7 with 235000 uses some oil and I also find some puddle underneath on occasion. However, the level seems to drop very gradual with little to no puddle then suddenly drop and puddle noticeably it also seems to lose power and run like a loud diesel. It then stops and goes back to runn i g better. Also what is average cost of a rebuild. Thanks.

 

Does it run better when you fill it back up with oil?

 

First, you need to find where the leak is coming from. That's going to involve getting under the truck, removing skid plates, etc. and having a good look. If there is lots of oil on the engine, get it warmed up, hit it with degreaser, and hose it down so you have a clean engine.

Next, if you think it could be coming from a hard to see area (i.e. rear main seal), you want to get a dye tracer kit. Some auto parts stores sell them, and they're easily available online. That and a UV light will help you track the source of the leak since the dye will glow under UV light.


Then, once you know where the leak is, you can devise a plan to fix it.


As for sounding like a diesel, the 3RZ-FE is a shim-over-bucket valve design, so the sound isn't from losing oil pressure in lash adjusters. So we can probably rule that out. If you are losing oil pressure, it could be starving the cams, which can cause noise, or it could be starving the main bearings, which will also cause noise (but more of a knock - I don't equate that with a 'diesel' sound).


If or when you top off the oil, how much are you having to add? In other words, when the noise comes around, how low are you on oil and does the noise go away when you top off the oil?


Without pictures or more information, it's basically impossible to help you further.