Why does an engine loose oil?

[JDraper]

Originally posted by rvitek
The 4.6L Northstar has 27K miles on it running 0W30 oil.
The 5.0L XLT has 47K miles on it running the same, 0W30 oil.

As a test, I'm going to switch back to GM/Ford-recomended oil-weights and dino oil on the next change to see what kind of consumption I get.

..
Ry.

That's what I was going to recommend. An 0 weight oil is very thin and may be seeping by the seals. I know people run it for better mileage, but the engines have tolerances built into them that are designed for a specific oil weight. Exceed that spec on either side and it can cause problems. Too thin and you get excessive consumption and you can cause premature bearing wear (the oil fills the space in between the bearings and the crankshaft, which is usually in the 0.002" to 0.004" range), too thick and you might not get enough lubrication to critical components. I don't think you need to go back to dino, but I definitely would suggest using the factory specified weights.

 

[rvitek]

Thanks for that recomendation - I'm definately switching back on the XLT as I'm nearing my change interval here pretty quick. I'll report back the status of that!

Hey Ross - where's the PCV valve on the 5.0s? I can't fint it for the life of me!

Ry.

 

[Ross-N-Chicago]

On a 2001 I don't know. It should be a small valve (swiss army knife size) on the intake manifold somewhere--bunch of lines coming out of it or near it.

 

[Texan01]

The Northstar V-8 is TOTALLY different than an LS-1. The LS-1 is a 16 valve pushrod OHV design, whereas the Northstar is a 4.6l DOHC 32 valve, all aluminum V-8.

LS-1 is for RWD, Northstar for FWD, altough you can get parts to convert a N-star to RWD.

 

[Bill Kemp]

Ryan, You have probably read this:http://caddymb.netgetgoing.com/messageDetail.asp?MessageId=9491
My 99 STS 64,000 mi. uses about a quart every 3,500 miles. I do drive it fast & like to wind out 2nd when passing on a two lane.
I guess it, oil consumption, just goes with the territory.

 

[EasyRhino]

Originally posted by rvitek
Thanks for that recomendation - I'm definately switching back on the XLT as I'm nearing my change interval here pretty quick. I'll report back the status of that!

Hey Ross - where's the PCV valve on the 5.0s? I can't fint it for the life of me!

Ry.

On my 97 5.0 it was sticking out the back/top of the intake manifold, total PITA to replace.