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Discussion Starter · #1 ·
Hey guys, would love your option on what to do. I've read a good bit of forums and stories but didn't find one quite like mine.

Some background...

My 09 MDX has been having oil consumption issues since like 127k which I've gotten used to. I'm now to the point of adding 1qt weekly or every 400 miles / gas trip. My X sounds/looks great mechanically. I live in a high elevation area (9k - 12k ft) so my driving habits and motor over all works harder than your average X. I run 5-30 full synthetic. Run the highest octane gas available which is 91 (we don't get 93 here).

The problem comes in when I pass 4k rpm. Whether I'm holding it there or going higher theres significant blue smoke and sometimes black coming from the exhaust along with a burning egg/grass smell in the cabin even when windows are closed and circulation is on. Noticeably worse when vtec engages. If I stay under 4k rpm then my oil consumption of course is somewhat normal, no smoke. I try my best to stay in this range but can't climb hills or merge at an appropriate pace.

I plan to use my X for towing soon and if I stay in the higher rpm's long enough I fear I'll burn through all of my oil while towing.

Power delivery feels just as it does brand new but the smoke concerns me. What do you suggest? I've even considered pulling the vtec solenoid so it doesn't engage but not sure if thats going to help much. From my knowledge this could be related to some kind of seal/sleeve?
 

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There are some interesting videos on youtube about "Restore" reducing oil consumption and increasing compression. Not much downside to trying. "Project Farm" has a good one on increasing compression.

Towing will definitely increase oil consumption as higher rpms are necessary; no overdrive usually.

If oil smoking appears after a prolonged idle or immediately on acceleration, valve stem seals may be leaking. I doubt any chemical treatment would affect valve stem seals.

good luck
 

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'adding 1qt weekly or every 400 miles / gas trip'

This is a lot. If you want to keep the car for a while, better find a professional to take a look.
 

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That is definitely end of life for that engine if it's truly burning 1q every 400miles. I would do a compression test to really know if the engine is shot.. If it is indeed over I would start to look into a donor engine if the car overall shape is sound and in fully working order there is no need to move on from it just for the engine.
 

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Discussion Starter · #6 ·
There are some interesting videos on youtube about "Restore" reducing oil consumption and increasing compression. Not much downside to trying. "Project Farm" has a good one on increasing compression.

If oil smoking appears after a prolonged idle or immediately on acceleration, valve stem seals may be leaking. I doubt any chemical treatment would affect valve stem seals.
Thanks for the vid suggestion. Forgot to mention that I have used a blow by / piston ring additive twice so far that seems to slow down consumption. Until of course I burn through it. No burning/smoke happens at idle, only in vtec range.

That is definitely end of life for that engine if it's truly burning 1q every 400miles. I would do a compression test to really know if the engine is shot.. If it is indeed over I would start to look into a donor engine if the car overall shape is sound and in fully working order there is no need to move on from it just for the engine.
Compression test is a great idea. I'll be setting up one soon and sharing the results. My only doubts/confidence comes from that I have no loss of power and rpm's/idle are stable. I want to revise and say its about 1qt every 800-1000 miles or 2 fillups with hard driving. (Hard driving = steady 4k+ rpm's for 2-4 minutes climbing hills) Also should to mention I had the rear main seal replaced last year because it was leaking thus causing the oil to disappear faster.

What gives me faith though is that if I baby it there's little to no burn at all. That's why I was curious if vtec could be disabled by removing a solenoid/relay.

If you want to keep the car for a while, better find a professional to take a look.
This is likely what i'll end up doing after trial and error. What bugs me is that once someone learns the amount of miles on the motor, assumptions and guesses are quickly formed which deters me from reaching into my wallet. From looking on ebay j37's in the 60k-90k mile range are quite affordable.

My main hunch is that this issue is linked to the piston rings failing under heavy load.
 

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Why would you want to remove the VTEC Solenoid? VTEC does not stress the oil at all, The solenoid just opens up a few extra passages of oil so the Rockers can lock into the high lobe for extra lift. Then the oil gets back into the engine oil pan and the cycle repeats, That oil is not stressed or burnt in any way.

In the case you want to avoid burning oil you should avoid any high rpm scenario where the engine oil is more likely to be burned due to the bore film being burnt in high rpm combustion. In low load the film is less likely to be burned.
 

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Discussion Starter · #8 ·
Why would you want to remove the VTEC Solenoid? VTEC does not stress the oil at all, The solenoid just opens up a few extra passages of oil so the Rockers can lock into the high lobe for extra lift. Then the oil gets back into the engine oil pan and the cycle repeats, That oil is not stressed or burnt in any way.

In the case you want to avoid burning oil you should avoid any high rpm scenario where the engine oil is more likely to be burned due to the bore film being burnt in high rpm combustion. In low load the film is less likely to be burned.
Then that's just my lack of knowledge of how it works. In my driving experience once I hear it engage that's when visible smoke/smell starts. I can replicate it every time. I also figure that's why 95% of the MDX's here have black exhaust tips and soot around the bumper like a diesel.

At 9,500k+ ft in elevation on steep grades I have to dip into 4k+ rpm's to pass/maintain highway speeds in 3rd gear. Loveland Pass and the tunnel here on i70 west tops out at 12k ft. I also own a Mazda 3 though not as heavy works just as hard. No way for me to avoid high rpm's unless I'm in the southern cities.
 
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