I've been looking for a budget car for a while as I really would like another MR2. I was wondering whether any of the mechanically minded members can answer this question that has always puzzled me.
I'm obviously aware of the oil burning issue that can occur and the reasons behind it. However, I've often read that owners have bought a car with, or just noticed that their car has, high oil consumption, sometimes as high as 1 litre per 600 miles yet the car doesn't emit any (or very little) smoke. Is this simply down to the cat doing its job? Only whenever I've had a car that uses a bit of oil it's always been fairly easy to spot.
I exchanged a few messages with a guy who said his pfl has been using 1 litre per 600 miles for the last 70k with no increase in consumption over that period! That's around 115 litres of oil! Surely that level of oil consumption would be relatively easy to spot if viewing an oil burner?
Secondly, I saw this picture in an advert for an oil burner;
(https://uploads.tapatalk-cdn.com/20170126/74896c613e78318d14ab4929a1321da7.jpg)
He's shown a picture of it smoking, presumably with the engine idling as there doesn't appear to be anyone inside the car. There appears to be lots of smoke hanging in the air which (to me) appears to be oil burning related smoke. I assume the engine in this car has ingested its precats, scratched its bores to pieces and is drinking oil at such a rate that it is simply overwhelming the main cat?
Also I assume the engine is likely to be completely goosed? I.e beyond a 'light rebuild'?
Was that pic taken when engine was cold?
Mine has been using about that for last 4 years about 30k, maybe slightly more if thrashed lol. Did get worse when PCV stuck. swapped it things improved.
Any oil leaks? cam chain tensioner "o" ring leaking, rocket covet leaking, sump/ oil filter etc leaks.
Quote from: "krazysteve"Was that pic taken when engine was cold?
Mine has been using about that for last 4 years about 30k, maybe slightly more if thrashed lol. Did get worse when PCV stuck. swapped it things improved.
Any oil leaks? cam chain tensioner "o" ring leaking, rocket covet leaking, sump/ oil filter etc leaks.
I don't know the circumstances of when that picture was taken and it isn't related to the earlier part of the post (regarding the chap I had been messaging) - just a picture I saw in an advert for car advertised as 'smokin hot'!
Does your car actually emit any smoke then? I'm sure I can recall people on hear in the past saying that they had pretty much run their engines dry in a few hundred miles but claim they wasn't aware it was burning any oil.
regards the picture
Looks classic cold start condensation to me.
Your other observation = true
Very hard to tell from the scock cock scock pit whilst driving if burning or not.
1 option, get someone to follow you.
option 2 (still not great) get up to temp find a long down hill get up to normal speed, lift off the gas for a while then back on. This may or may not help in "seeing" if it is burning. (good chance there is a little bit more detail required in doing this. Others will correct as required)
Option 3. Top up - drive -monitor.
Mr T deems a litre per 1000Km (620m ish) to be acceptable.
Depends on the oil used as well as to how visible it is. Oil burning isn't as visible these days with new oils anyway
Just my 2 cents here... I was using semi synthetic and seemed to use maybe 750mls every 6 months for a daily driver (30 mins commute).
6-7 months ago I changed to fully synthetic (Fuchs) and have not been able to detect ANY drop in the oil level.. Despite bordering on OCD checking....
I'm sure it doesn't help, but it's just my experience.
That ain't no accident. Check out the differecnes between synth and semi.
I wouldn't run semi again. Same way I don't use a wired phone anymore; there's a better alternative now
Most oil-burners don't show any visible smoke, and they pass MOT emissions tests. That's because the oil comes past the oil control rings when the engine is under load and all the oil is burnt as extra fuel. There are cases where blue smoke does show up and that is usually a result of bad valve-stem oil seals which will leak at idle. The PCV valve shows as blue smoke after the engine has been on over-run (such as downhill in gear with the throttle shut), you see a puff of blue when you next use the throttle.
Many live with oil consumption at the 600-1,000 miles per litre level for years.
The PCV valve is an very easy fix. The other two require an engine rebuild to cure.
As a rule of thumb: Blue smoke when accelerating; piston rings. Blue smoke on the over-run and at idle; valve stem seals. Blue smoke when getting back on the throttle (just a 'puff which soon clears); PCV valve.
Fully synth oil is a must.
This one is quite interesting. Ignore the blabbel and start at 5:26.
m https://youtu.be/tYkg0oDUXs8?t=5m26s (https://youtu.be/tYkg0oDUXs8?t=5m26s) m
This is what finalised it for me. Fully synth does its job better, for longer. Especially in the temperature changes we see here. So, I know that by the time I change the oil, it's still doing it's job. Whereas a semi synth wouldn't be.
And as the engine does "live" around 4-6k rpm (or where I make it live), that all matters to me s:) :) s:)
Thinking about the original question, which was (basically) 'how to spot an oil-burner'.
Pull the dipstick and check the colour of the oil. If its dark, it's almost certainly consuming oil. It is dark either because the oil hasn't been changed in ages or because poor oil control rings result in dark oil.
Any older car that hasn't had engine work will probably consume some oil, that's a generalisation, but good 90% of the time.
That helps no end Carolyn, thank you - so (generally speaking) if viewing a car and there is no obvious blue smoke (and you can't provoke any under load or on the over-run etc) the worst case scenario is that a 'light rebuild' might be on the cards at some point, as in re-hone the bores, clean the pistons (maybe modify?), replace rings, valve stem seals and a relap the valves?
Obviously seeing it from a cold start and then fully up to temperature to listen for any unwanted noises too.
Always use fully synth and have done for many years. After seeing that video Shnazzle, I won't be using anything else anytime soon, good use of visuals in the video to get the point across.
You got it. Engine rebuilds are fun if you take your time and it's satisfying to know you did it and your little car is set up for many happy miles.
Quote from: "Carolyn"You got it. Engine rebuilds are fun if you take your time and it's satisfying to know you did it and your little car is set up for many happy miles.
That is what I was hoping. Did a similar thing (well did it together with my father) around 25 years ago on a simple engine. Although it was FWD and there was a lot more space around the engine, which we didn't need to remove from the car. Bit more cramped on the two!
In fact, we had the head off twice as we mis-diagnosed the valve stem seals as the problem. Re-seated the valves and re-assembled which seemed to make it worse. Turned out to be gummed up piston rings so we got there in the end.
Cockpit, lol.
Now trying to work out why shows censord in my post but not yours.
GO here:
l ucp.php?i=ucp_prefs&mode=view (http://www.mr2roc.org/phpBB3/ucp.php?i=ucp_prefs&mode=view) l
what does it say for censoring?
Says enable word censoring
Set to no.