[ixthnar]

Related to post Oil (coolant) Leak *front* right

I purchased my 2008 Smart ForTwo Passion new in 2008. The only mod is an upgraded stereo. Maintenance has always been at still per manufacturer specifications. Have always used Mobile 1 full synthetic. I started using Mobile 1 0W40 (zero w forty) the European spec when I moved from Texas to Colorado in 2018.

In 2019 the oil pan cracked at garage, I spotted the leak, and subsequently replaced the oil pan. This is the only time the oil has been below full.

In the early of morning of 2020/10/17 the car hit a fawn rolling over part of it on the passenger side.

• Going 75 mph just before hitting deer
• Hit and rolled over part of deer slowing 40 mph
• Car continued to run normal and I did not stop
• An hour or so later the oil light started flashing. It was never solid on. I stopped at the next service station and it took 2 quarts to get it to full. I also noted and cleared code P0011 which never recurred.
• Started using an OBD2 app (Torque Pro) to monitor events, coolant temperature, and air intake temperature. They stayed in normal ranges the remainder of the trip. (The coolant ranged from 194 to 200.)
• I completed the 1,000-mile trip at normal speeds, 65 to 75, stopping every 1/2 tank of gas to check the oil. In total I added 8 quarts. I noticed a pending code P0303 (cylinder 3 misfire) which may have happened when the P0011 happened.

Here is what we found trying to diagnose the oil loss.

• Engine runs smoothly with normal power. Drove a usual, hilly route to verify power.
• A mechanic found a coolant leak but no other sign of fluid/oil leakage
• Used a mirror and flashlight from above and below to inspect the engine and the belly pan. There was no oil or oil stain. There was dried blood and fur on the rear axle beam and oil filter.
• Watched with engine running and at 3,500 RPM (no load) without seeing any smoke, spray, or dripping
• No oil in coolant or vice versa. Head gasket okay.
• Exhaust transparent, zero smoke, for cold start, cold running, hot start, or hot running. Rings and valves are okay.
• The oil filler hole has no air flow (i.e. valve seals are good)
• The oil filter is not loose but may have damage that only shows when the engine is under load at high rpms. It is positioned such that any leak at highway speeds would likely blow off without leaving a trace (except on the filter itself).
• The one-time P0011 code and pending P0303 code have not helped narrow the search

We will change the oil and filter hoping that the oil filter is leaking a highway speeds. At this time we will check the compression just to touch that base.

 

[SLIVERS]

If it's not leaking out the engine it's burning it.
Gonna say valve guides?
Been there!

 

[ixthnar]

If it's not leaking out the engine it's burning it.
Gonna say valve guides?
Been there!

Thanks. The zero smoke on start and idle plus sudden onset complicate this. If it were burning only at higher RPMs and underload, what would cause that and/or how could it be detected (aside from loss of oil)?

 

[smark]

One of the moderators, should combine this post, with its similar one. From the same Op.

 

[SLIVERS]

Lived through the PO133 codes, then fouled plugs and using oil for over as year.
With modern cars one generally doesn't see the "burning" oil like in the old days because of the catalytic converter.
Check your spark plugs for any sign of fouling?

 

[ixthnar]

Lived through the PO133 codes, then fouled plugs and using oil for over as year.
With modern cars one generally doesn't see the "burning" oil like in the old days because of the catalytic converter.
Check your spark plugs for any sign of fouling?

Thanks. Planning a compression test. This will be a natural part of it. btw ... I changed the plugs 6+ months ago when a bit of spilled oil (from last change by garage) leaked in passed the coil pack -- got a big puff of smoke out of that. Cleaning that up is why the engine is clean now.

 

[SLIVERS]

Compression checks on mine were good all the way up till a piece of valve broke!

 

[Jersey Smart]

if there is no sign of a leak, the engine must be burning it. With radiator damage it is more than likely the engine has been running too hot. Don’t rely on the idiot gauge to let you know. Synthetic oil of today does not show smoke. Pull the plugs and inspect. You should see signs there.

 

[ixthnar]

The problem is resolved! A problem with the PCV Valve only caused a problem when the engine had a heavy load. An 80 mile drive under 50 mph without passing or powering up hills ... no oil loss. An 80 mile trip powering up a mountain (5,600 ft to 11,000 ft) and mostly doing 70 mph lost nearly a quart of oil. The oil was being burned but only when I was going fast enough that it dispersed too rapidly to be seen.

btw ... The PCV valve hides on the front of the engine. The engine has to be dropped to replace it.