I'm just at the start of this journey, haven't actually done much other than some research.

Car: 2003 AP1 with 98,000 miles. Mobil 1 10W-30 for most of its life. The past handful of oil changes have been with Mobil 1 High Mileage.

Symptom 1: Continuous oil smoke out of tailpipes during VTEC.
Symptom 2: Very slight oil smoke (just a single puff, really) out of tailpipes when starting from a stop.
Symptom 3: Overall heavy oil usage, about 1qt per 1000mi. (Although this is often considered normal for an AP1.)

Theory 1: During VTEC, the oil that operates the VTEC pins drains out into the valve train area. Due to a leaking valve stem seal, this extra amount of oil enters the combustion chamber and produces the smoke.

Theory 2: During idle at stops, oil accumulates in the valve train area, then gets forced past the leaking valve stem seal when revs are increased to start moving.

Theory 3: In the above situations, the smoke is from oil being sucked up through the PCV valve and into the intake manifold.

Theory 4: It's all due to the Mobil 1 somehow.

So far I've only run some carb cleaner through the PCV valve to make sure it’s clear. I checked the hose from the PCV to the intake manifold - it didn't appear to be wet from oil, but the car had sat for a couple days at that point so I want to re-check it after a VTEC run.

Is it worth getting a compression check or leak down test? Posts I've read about the above symptoms indicate people with the same problem don't show anything wrong with those tests so I'm not sure it's worth bothering with.

Quick potential fix - Just use some Amsoil for the next oil change. It seems to get good reviews here, but not across the board.

Relatively easy potential fix - install an oil catch can.

More involved potential fix - replace the valve stem seals. Except for basic tools, a spring compressor, and something to pressurize the combustion chamber so the valves stay up, what's required? (Might as well replace the intake valve retainers with AP2 parts too.)

Can anybody suggest any further diagnostic or potential fix steps I should take?

I'll post further updates as I try things or find out things.

Thanks!

 

I think you would have to take the whole head off for valve stem change, but I could be wrong. Try switching to Castrol edge 10w-30, my AP1 barely burns any. As far as smoke goes I would say that close to normal as I have seen many AP1 smoke on take off and during VTEC, including mines sometimes.

 

Wrong......valve stem SEALS can be done with the head still on the car no problem. it'd be wise to have the special tool for removal though so you don't damage your valve stems. And smoke is not "normal". These cars never smoked from the factory, so it's not "normal". It is however common. As parts wear down so does the sealing capabilities of the engine. I would replace the valve stem seals, and look into an 04-05 valve cover with the better PCV system. If that doesn't solve it, you most likely are experiencing heavy blow-by past the piston rings and is more evident in VTEC since the motor is rotating a lot faster. Keep this thread posted though on your possible resolve.

 

It used to smoke on my first Honda Prelude, valve stems solved it for me back then. But, for oil burning, I have had 3 5th gen Preludes and 1 4th gen prelude and now S2000, all of them with no exceptions burn around 1 quart of oil every 1000 miles.

 

yea mine use to burn oil but once i went with this oil it stopped, and after i installed my test pipe,i notice some smoke sometimes not always

 

i dont know but i think i was behind you after bjs brewhouse in plano we were on 75 heading to a performance shop in Addison and that was alot of smoke if not you my apologies but i would do a leak down test to make sure its not a worn cylinder and yes you can do valve stem seals in car let me know i was looking to buy this but its expensive let me know i can do the work and would do it for cost of tool i have ap1 and want to do ap2 keepers pm me if your intrested
Buddy Club Valve Springs Changer Tool Kit (Honda K and F Engine)

 

My '00 has fewer miles (under 70K) but I have not noticed or been told of excessive smoking... my oil consumption was increasing while I still used M1, in fact after a hard 1K drive I could be down almost a quart but since I switched to other synthetics it is lower... my last group trip that included some vtec and at least 50 miles over 100 had no oil use (pennzoil ultra 10w30).

I was surprised to see you have an '03 and thought you were still driving the original black '00.

Sounds like you need to pursue the component wear possibility but a different oil may reduce the issue for awhile.

 

Is it blue smoke or black smoke? black smoke in VTEC is a rich air fuel, blue is oil seepage. If it is blue smoke all the time you are going to need to replace some parts or re-build.

High mileage oil is good for worn seals, I'd keep running it for a while see if it helps swell your seals a bit. Maybe change the brand of high mileage oil, if you can run a thicker version like Castrol 10w30 High Mileage. At this point I'd shy away from synthetic oil even Amsoil, I don't think that will solve the issue.

Sometimes changing the pcv valve can help, running an ap2 (04-05) valvecover can help as well, but I think your issues are due to worn engine parts. 1 quart per 1000 miles is the dividing line for a worn engine, right now it is okay if it stays at that level, if it gets up to 1.5 quarts per 1000 miles then you definitely have an engine parts issue.

 

Your valve stem seals are probably just fine. I don't think FRM is very kind to oil control rings...

 

This sound very similar to my AP1, I replaced the Valve Stem seals when I upgraded my Valve springs, retainers (AP2 intake and new AP1 exhaust)and valve adjustment without taking the head off.

fixed the Problem in my case and my car is at 220,000Kms