Oil smell at startup?

paperfist

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Nov 30, 2000
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2010 Prius, 200k. Run Royal Purple 0-20.

Just starting to notice a faint oil smell usually at start up. I haven't noticed any leaking.

Rings, right?

If so how long do I have? Will anything like Engine Restorer work?
 

eng2d2

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Nov 7, 2013
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Are you sure you don’t have any leaks. PleSe check again. Do you know where to inspect for leaks
 
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paperfist

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Are you sure you don’t have any leaks. PleSe check again. Do you know where to inspect for leaks

I haven't dug into the engine bay yet, but I figured I'd see some oil on the pearly white snow I park on top of.

Checked the oil again and it's still at the full line after 1.5 months since the oil change.
 

tracerbullet

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Feb 22, 2001
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I was thinking valve seals. Leaking down into the cylinders when the engine is off.

Honestly it could be either, at 200k you could certainly believe the rings were giving up. But I'm thinking for start-up I'd look at valve seals, maybe not instead but at least in addition.
 
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mindless1

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Oil smell at the engine or out the exhaust? Could be something as simple as a valve cover gasket leak if at the engine.

Oil past rings or valve seals should not produce an oil smell at the engine unless something else is allowing that to vent out like a clogged PCV system.
 
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paperfist

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I was thinking valve seals. Leaking down into the cylinders when the engine is off.

Honestly it could be either, at 200k you could certainly believe the rings were giving up. But I'm thinking for start-up I'd look at valve seals, maybe not instead but at least in addition.

Thanks, didn't even think about that.

Oil smell at the engine or out the exhaust? Could be something as simple as a valve cover gasket leak if at the engine.

Oil past rings or valve seals should not produce an oil smell at the engine unless something else is allowing that to vent out like a clogged PCV system.

Engine.

I was attempting to look at the exhaust, but the way the engine is off mostly at idle it's tough to track down.

I could have sworn I just had the PCV valve changed, but who knows with the last mechanic I had. I'm gonna change it out again for the heck of it.
 

jlee

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Sep 12, 2001
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I was thinking valve seals. Leaking down into the cylinders when the engine is off.

Honestly it could be either, at 200k you could certainly believe the rings were giving up. But I'm thinking for start-up I'd look at valve seals, maybe not instead but at least in addition.

++

Oil burn on cold start sounds like valve stem seals to me.

Edit: Just saw that you're smelling it at the engine, not exhaust - that may be a gasket leaking oil onto an exhaust component.
 

mindless1

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Aug 11, 2001
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Thanks, didn't even think about that.

Engine.

I was attempting to look at the exhaust, but the way the engine is off mostly at idle it's tough to track down.

I could have sworn I just had the PCV valve changed, but who knows with the last mechanic I had. I'm gonna change it out again for the heck of it.

Could be the (new) valve is good but changing it tore the pipe or hose to it, gasket around it so it doesn't seal, or ??? Even so I'd sooner suspect a valve cover leak onto the engine. If that's what it is you should see residue, maybe even fumes when you smell it.
 

mizzou

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Jan 2, 2008
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I had a engine oil filter fail and it caused a noticeable oil smell. DIdn't realize what it was until I did my next oil change. Sometimes they can be perforated or just somehow got loose.
 

razel

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May 14, 2002
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200k miles, 20 weight oil. Don't be surprised if this is just the beginning of a costly maintenance trip. I'd take it to a shop with a mechanic you trust.
 
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paperfist

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200k miles, 20 weight oil. Don't be surprised if this is just the beginning of a costly maintenance trip. I'd take it to a shop with a mechanic you trust.

That's pretty much my concern. It's due for an inspection so I'll drop it off soon.

The smell seems to be intermittent and the dipstick is still at full.

I've never used one of those oil same analysts places before but I think I'm going to try it out.
 

razel

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Oil analysts like Blackstone Labs is awesome. Your car hitting 200k is awesome too. It is entirely possible the seals are sweating. My previous car was 180k. It began to seep oil all around the valve cover. Not a full leak. The heat of the engine would just cause it burn up and smell the engine bay. Only evidence was a buildup of dirt and oil that never dripped.

My mechanic called it sweating seals and didn't recommend fixing it since the labor was expensive. He just tightened up the bolts and recommended washing the engine if it really bothered me.
 
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mizzou

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Before you put the cart before the horse...why are you necessarily wanting to fix this? I don't think it would hurt to send in an oil for a lab test, but if everything is otherwise functioning correctly (RPMs, Temp, fluid levels, idle), why fix something that isn't broke?

"Faint" at 200k, that sounds pretty normal right? Or is this more of a concern because it is a hybrid vehicle? I don't know anything about hybrid power systems.
 
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Feb 25, 2011
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I'm in the "probably a very small leak dripping a little oil onto an exhaust manifold or something" camp.

You getting any blue smoke?
 
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crashtech

Lifer
Jan 4, 2013
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A small oil weep from the valve cover onto the exhaust manifold, as has been mentioned. It won't hit the ground until it gets worse, because it's getting burned away. A leak that small will take many months to be noticed on the dipstick, if it's noticeable at all that way.
 
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paperfist

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Oil analysts like Blackstone Labs is awesome. Your car hitting 200k is awesome too. It is entirely possible the seals are sweating. My previous car was 180k. It began to seep oil all around the valve cover. Not a full leak. The heat of the engine would just cause it burn up and smell the engine bay. Only evidence was a buildup of dirt and oil that never dripped.

My mechanic called it sweating seals and didn't recommend fixing it since the labor was expensive. He just tightened up the bolts and recommended washing the engine if it really bothered me.

Thanks for the heads up on Blackstone, saves me from searching google for 2 hours ;)

Sweating seals sounds like good news lol. I'll check into that.
 

paperfist

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Before you put the cart before the horse...why are you necessarily wanting to fix this? I don't think it would hurt to send in an oil for a lab test, but if everything is otherwise functioning correctly (RPMs, Temp, fluid levels, idle), why fix something that isn't broke?

"Faint" at 200k, that sounds pretty normal right? Or is this more of a concern because it is a hybrid vehicle? I don't know anything about hybrid power systems.

It's really uncharted territory for me in both that it's a hybrid and I've never been anywhere near 200k so I'm not familiar with this oil smell and if it's okay or not. I like to be proactive and do maintenance before problems arise. My last vehicle was a Colorado and it drove my mechanic nuts when I had him change the water pump, battery, belt, alternator, etc before they showed signs of any problems.

I'm in the "probably a very small leak dripping a little oil onto an exhaust manifold or something" camp.

You getting any blue smoke?

I haven't seen any blue smoke, but it being a hybrid it's hard to pin point that because the engine doesn't really run at idle or start up for any period of time.
 
Feb 25, 2011
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I haven't seen any blue smoke, but it being a hybrid it's hard to pin point that because the engine doesn't really run at idle or start up for any period of time.

Check your manual - I bet there's a way to force the engine to run. (Maybe "charge" or "sport" mode or something.)