Posted a while ago about my F8 engine in a Nissan Vanette smoking most mornings on startup. Had waterpump/cambelt/head gasket/valve stem seals replaced and now its much, much worse. to the point of not being able to see the neighbours house this morning. lol Does not burn oil, and now will not smoke for the rest of the day. This must be broken oil rings? Someone mentioned cat converter may be blocked, but it runs really well. sounds terminal to me. Any other possibilities before I leave a brick on the accelerator and watch the thing explode?
kazbanz,
Sep 8, 6:01am
I know we went through it but what color is the smoke?
ambo11,
Sep 8, 6:08am
Hi Kaz, blue, oil smoke. then after 5 minutes it clears to the steam/condensation of a cold morning startup. got me baffled, as it does not use oil that I've noticed. motor is quiet, performs "okay". annoying as the van is useful being 4wdl, but worthless in reality. can get a rebuilt motor for $2300 but thats the whole van value. Frustrating.
tony9,
Sep 8, 6:19am
Got to be inlet valve seals. Are they fitted the right way around?
Or the Crankcase ventilation is leaking into the intake manifold overnight. PCV valve?
ambo11,
Sep 8, 6:26am
All work done by qualified mechanic with valve stem seals fitted by local motor engineers. mechanic wondered if it had stuck rings. wasn't a sure fix, but doing valve stem seals was a cheap option. Maybe I better go buy an old Falcon to tow the trailer.
tony9,
Sep 8, 6:52am
Don't see how stuck rings is going to cause smoke at startup. Compression test will check that fairly easily.
Although I suppose stuck rings will load up the crankcase ventilation and put oil into the intake that way. PCV should be moderating it though.
ambo11,
Sep 8, 6:54am
Will try and find PCV and maybe try another from a wrecker? Thanks
mrcat1,
Sep 8, 7:24am
They should do a compression test AND a leak down test to see what's happening, if its broken compression rings then it would have low compression, if its broken a oil control ring then it will smoke all the time and tend to use it.
mrcat1,
Sep 8, 7:25am
Why did they pull the head off to do valve seals? they can be done in place.
bobin55,
Sep 8, 8:53am
try looking at the brake booster leaking fluid in over night making bright blue smoke when started
mrfxit,
Sep 8, 10:37am
Yep as above. Broken compression rings will give low compression but won't smoke Broken oil control ring will burn oil all the time but compressions will be ok Blocked PCV valve will create excess pressure in the sump forcing oil out the seals. Inactive PCV valve will suck the oil out of the sump in to the inlet manifold A sticky open PCV valve will stick while the engine is cold creating smoke till the engine is warmer or enough vacuum has been created to close it High vacuum pressure through the PCV valve will empty the sump Worn valve stem seals only generally smoke at start up or directly revving after a long idle & downhill runs. Brake fluid seeping in to the manifold through a brake booster seal will generally always smoke but is normally white to gray in color
mrfxit,
Sep 8, 10:39am
Thinking . >>
Worn valve stem seals would create a higher flow through of vacuum pressure from sump to PCV valve.
You just sealed the valves possibly creating that bit extra vacuum that the PCV valve can't handle ?
woki,
Sep 8, 10:47am
Check this ! If the PCV valve is allowing oil to get sucked into the inlet manifold and burning it thru combustion . When you turn the engine off and let it sit all the residue oil left in the manifold will run to the lowest point . usually inlet port . when the cars starts after sitting for a while it will smoke like crazy on start up . Check the PCV valve and also check inside of the manifold for oil build up . Hope this makes sense !
ambo11,
Sep 8, 11:40am
Cheers guys, spoke with my mechanic who thinks its rings, but will suggest PCV valve. I trust this guy totally and know he is honest, so am getting a quote for rings/bearings.He used to service these motors all the time at the Mazda dealer so is pretty quick at working on them. He did mention the valve stem seals "may not" solve anything before I got it all done. He can access a PCV valve to try out first. Its a case of the vehicle isn't worth anything in monetary terms, but is worth a lot to me in its space, and 4WD usefulness. plus now he has done the head etc, it runs nicer with more "pep". Not interested in a S/H motor as its unknown, and an old Coon or Commodore as a tower will still no doubt cost $$$ and isn't as useful as a van, so may as well fix the one I know. Tits or tyres, it'll cost ya.
skiff1,
Sep 8, 2:38pm
I can only point out that it got worse after all those parts were replaced, got to be one of those parts? Valve stem seals strike me as the issue. Doesn't matter who fitted them, even the best can make a mistake.
saki,
Sep 10, 3:46pm
May be you are getting fuel into the sump, keeping the level fairly constant, burning of enough oil to keep the level steady, or vice versa.
ambo11,
Sep 10, 4:30pm
Yeah I dunno. its changing daily. now won't smoke till its been running a minute or so, then away it goes,smoking until the engine warms up, then smoking stops. Just waiting to hear back when the mechanic can do the rings/bearings. This was imported in the days of odos being wound back (not digital) so who knows what the "actual" mileage is. I'm happy to get rings/bearings done anyway, its such a useful vehicle to me. I'm wondering if it has cracked some oil rings, before I purchased it, it spent its life mucking round town at 50km/h towing a light trailer sometimes with branches on. and the oil was just black soup. The previous owner didn't believe in servicing. I bought it, serviced it and worked it hard, so maybe that has something to do with it.
intrade,
Sep 10, 4:36pm
if it dont uses oil then its not the engine oil making the smoke. i came down whakapapa yesteday and at the bottom stop sign i put the car behind me in a blue cloude of smoke as i happened to look in the mirror when i took off, that is valvstem seals when its doing exactly that. No fuelinjected down hills for miles and miles and then when you boot it again pooof smoke like hell out the exhaust its using 1 liter or so oil for 1500km
321mat,
Sep 11, 9:00am
IS the transmission over-filled?
Often, as you describe what happened to you at Whakapapa, if the transmission has been overfilled with oil, the fluid can get pumped out through the overflow line on deceleration (esp. when hot), or when first started from cold.
intrade,
Jul 10, 11:33am
no its the valvestems it only does it when the fuelinjection is off for a long time , on overrun down hills if i give it a bit of throttle every now and then it wont do it , i recon it washes all the oil in to the engine accumulated on top of the valves when you come out of overrun and the injectors start to spray again . I know the injectors are off in overrun i got a youtube showing that with my handheld scope on dashboard
also the most vaccume you get on a old petrol engine with throttle closed -sucking like mad on them valvstems with closed throttle .
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