Need help (Smoke from exhaust during warm-up -- ?)
04-29-2002, 01:09 AM
#1
Advanced
Thread Starter
Join Date: Jan 2002
Location: Sarasota, Florida USA
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Need help (Smoke from exhaust during warm-up -- ?)
I would really appreciate some help or ideas regarding a smoking issue that just happened for the first time (I checked the archives and didn't find an answer there).
When I started my '89 964 after it had been sitting for 12 days, it put out quite a bit of white smoke for about a minute or so (enough that it fairly well filled the air in my yard with smoke). I went back and checked and it was coming from the exhaust pipe and was definitely not water vapor (it stunk up the garage and some of the house and, as noted above, stayed together as it drifted through the yard).
It has never had any exhaust smoke before at any time (start-up or while driving) and it did not continue to smoke during normal operation (including a subsequent restart) after this initial event. As an additional FYI, it leaks a small amount of oil when it sits this long (maybe 5 or 6 drops).
This car often sits for 10 - 14 days between drives so this really concerns me -- the motor had a top-end re-build 5,000 miles ago and had an oil change very recently (about 475 miles ago). I'm still using Castrol 20-W-50 per my mechanic's advice until the seals are fully set (then I will switch to Mobil 1).
This car has never been run really hard (no track use and never street-raced) and nothing unusual happened on my last drive (12 days ago) before this occurred.
I saw something on a previous post (from Adrian) about a relief valve issue -- could this possibly cause the smoking situation I'm describing?
My only other thought is that the motor stopped at an exact point where oil could leak into a cylinder (forgive me if this is way off base -- I had a Mazda that would do this occasionally so that's why I'm bringing it up).
Any thoughts or advice would be most appreciated (I plan to start the car again tomorrow after it has sat for 48 hours to see if any smoke is again present).
Thanks...
Tim <img src="confused.gif" border="0">
When I started my '89 964 after it had been sitting for 12 days, it put out quite a bit of white smoke for about a minute or so (enough that it fairly well filled the air in my yard with smoke). I went back and checked and it was coming from the exhaust pipe and was definitely not water vapor (it stunk up the garage and some of the house and, as noted above, stayed together as it drifted through the yard).
It has never had any exhaust smoke before at any time (start-up or while driving) and it did not continue to smoke during normal operation (including a subsequent restart) after this initial event. As an additional FYI, it leaks a small amount of oil when it sits this long (maybe 5 or 6 drops).
This car often sits for 10 - 14 days between drives so this really concerns me -- the motor had a top-end re-build 5,000 miles ago and had an oil change very recently (about 475 miles ago). I'm still using Castrol 20-W-50 per my mechanic's advice until the seals are fully set (then I will switch to Mobil 1).
This car has never been run really hard (no track use and never street-raced) and nothing unusual happened on my last drive (12 days ago) before this occurred.
I saw something on a previous post (from Adrian) about a relief valve issue -- could this possibly cause the smoking situation I'm describing?
My only other thought is that the motor stopped at an exact point where oil could leak into a cylinder (forgive me if this is way off base -- I had a Mazda that would do this occasionally so that's why I'm bringing it up).
Any thoughts or advice would be most appreciated (I plan to start the car again tomorrow after it has sat for 48 hours to see if any smoke is again present).
Thanks...
Tim <img src="confused.gif" border="0">
04-29-2002, 01:58 AM
#2
Race Car
Oil does tend to seep into the cylinders on a 911, especially if it sits for any length of time. My only suggestion is what you have already guessed...just risidual oil that seeped it's way into the combustion chambers after sitting for awhile.
You may have been slightly overfilled with oil as well...and it's slowly burning off until it reaches the proper level?
Was the morning that you had the problem fairly cool with high humidity? If so, that's where I find that the exhaust just kind of "lingers" about upon startup.
You may have been slightly overfilled with oil as well...and it's slowly burning off until it reaches the proper level?
Was the morning that you had the problem fairly cool with high humidity? If so, that's where I find that the exhaust just kind of "lingers" about upon startup.
The following users liked this post:
nabfa1 (09-02-2023)
04-29-2002, 03:29 AM
#3
Tim:
If this was a one time thing, I don't know if I would worry about it too much, particularly if the car sits for nearly two weeks at a pop before driving it. Did the odor smell like gas or oil?
Maybe you ought to try firing it up on a daily basis for a while and taking it for a short drive to get it warmed up to see if the problem has any degree of consistency.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
If this was a one time thing, I don't know if I would worry about it too much, particularly if the car sits for nearly two weeks at a pop before driving it. Did the odor smell like gas or oil?
Maybe you ought to try firing it up on a daily basis for a while and taking it for a short drive to get it warmed up to see if the problem has any degree of consistency.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
04-29-2002, 10:52 AM
#4
Advanced
Thread Starter
Join Date: Jan 2002
Location: Sarasota, Florida USA
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Jeff and Bill -- Thanks for the input.
Here's an update -- when I started it again this morning (after it had sat for 48 hours), there was absolutely no smoke whatsoever.
It was not "cool" the morning that the smoke incident occurred (probably about 75 degrees F), although the humidity was high (and it was really puffing the smoke out). I tried to smell the smoke and, although it did not smell like oil or gas to me, my wife had the garage opened up when I returned from my drive due to the stench left in there and part of the house (and we've never had this odor problem before when the car is started up).
I thought of the possible overfill issue while I was drafting my post on this so I will check that out after allowing it to warm-up properly.
As I had said, this car often sits for extended periods of time between drives (sometimes as long as 3 weeks
) and this had never happened before. I am hoping it will become more of a daily driver here real soon so then I'll see if there is any consistent additional occurrences.
If it just happens every once in a while due to the motor stopping at an exact point where oil can seep into a cylinder, that's not a big deal; but if there is something on the motor that I should check, than I would like to look into it (obviously my BIG concern would be that there is a problem related to the recent rebuild).
Tim
Here's an update -- when I started it again this morning (after it had sat for 48 hours), there was absolutely no smoke whatsoever.
It was not "cool" the morning that the smoke incident occurred (probably about 75 degrees F), although the humidity was high (and it was really puffing the smoke out). I tried to smell the smoke and, although it did not smell like oil or gas to me, my wife had the garage opened up when I returned from my drive due to the stench left in there and part of the house (and we've never had this odor problem before when the car is started up).
I thought of the possible overfill issue while I was drafting my post on this so I will check that out after allowing it to warm-up properly.
As I had said, this car often sits for extended periods of time between drives (sometimes as long as 3 weeks
) and this had never happened before. I am hoping it will become more of a daily driver here real soon so then I'll see if there is any consistent additional occurrences.If it just happens every once in a while due to the motor stopping at an exact point where oil can seep into a cylinder, that's not a big deal; but if there is something on the motor that I should check, than I would like to look into it (obviously my BIG concern would be that there is a problem related to the recent rebuild).
Tim
05-02-2002, 08:05 PM
#5
Instructor
Join Date: Apr 2002
Location: Caversham, Berkshire, UK
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
Guys
I had a complete rebuild done by AFN including valve guides, polished heads, oil seals, new rings (although the bores still showed the factory milling marks so wear was minimal) and experience similar white smoke most mornings. I mentioned this to the guys at Reading who did the work and they told me that 'as these are dry sump engines there is always oil residue in the heads to protect them' so what I'm seeing is burn off, 'it's normal and not to worry.'
You have now got me all worried again.
Leslie
I had a complete rebuild done by AFN including valve guides, polished heads, oil seals, new rings (although the bores still showed the factory milling marks so wear was minimal) and experience similar white smoke most mornings. I mentioned this to the guys at Reading who did the work and they told me that 'as these are dry sump engines there is always oil residue in the heads to protect them' so what I'm seeing is burn off, 'it's normal and not to worry.'
You have now got me all worried again.
Leslie
05-03-2002, 01:13 AM
#6
Advanced
Thread Starter
Join Date: Jan 2002
Location: Sarasota, Florida USA
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Leslie,
You share the same concern I had when I saw all that smoke (that there was a potential problem with the re-build), although my car did it just the one time.
I hope some of the other, more experienced owners chime in on this one to help you out as I really don't have too much additional input.
As an "FYI", my car's oil level does appear to be too high and this will cause the motor to have a better chance of smoking (so you can at least check that one thing). My oil level appears to be above the flat part of the dipstick (where the measurement notches are) about 1/2 inch up the round part. I am taking it back into the shop for a professional evaluation and to have the appropriate amount drained off.
My mechanic advised to pull and replace the dipstick about 4 or 5 times (wiping it clean each time) before you take the actual reading to allow all the residual oil that has blown up the dipstick tube to be removed from the area above the measurement notches. And, in case you don't know, the motor has to be FULLY warmed up prior to checking the oil (a minimum 15 minute drive is recommended).
Apparently, as the motor cools, the oil settles out and the higher the level is, the better chance it will leak into one of the cylinders.
Hope you get your situation figured out...
You share the same concern I had when I saw all that smoke (that there was a potential problem with the re-build), although my car did it just the one time.
I hope some of the other, more experienced owners chime in on this one to help you out as I really don't have too much additional input.
As an "FYI", my car's oil level does appear to be too high and this will cause the motor to have a better chance of smoking (so you can at least check that one thing). My oil level appears to be above the flat part of the dipstick (where the measurement notches are) about 1/2 inch up the round part. I am taking it back into the shop for a professional evaluation and to have the appropriate amount drained off.
My mechanic advised to pull and replace the dipstick about 4 or 5 times (wiping it clean each time) before you take the actual reading to allow all the residual oil that has blown up the dipstick tube to be removed from the area above the measurement notches. And, in case you don't know, the motor has to be FULLY warmed up prior to checking the oil (a minimum 15 minute drive is recommended).
Apparently, as the motor cools, the oil settles out and the higher the level is, the better chance it will leak into one of the cylinders.
Hope you get your situation figured out...
05-03-2002, 10:56 AM
#7
Instructor
Join Date: Apr 2002
Location: Caversham, Berkshire, UK
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
SuperCarerra
Not wishing to 'dis' anyone but I always check my oil using the method that AFN technicians use and showed me when I picked the car up from them after the rebuild which is:
1. 'ignore the dipstick'.
2. I run the engine up to temperature and ensure the oil thermostat has opened.
3. Leave the car ticking over and fill while watching the level gauge on the instrument cluster until it is just over the horizontal line.
Now I'm going to be bombarded by people telling me this is wrooong!
Not wishing to 'dis' anyone but I always check my oil using the method that AFN technicians use and showed me when I picked the car up from them after the rebuild which is:
1. 'ignore the dipstick'.
2. I run the engine up to temperature and ensure the oil thermostat has opened.
3. Leave the car ticking over and fill while watching the level gauge on the instrument cluster until it is just over the horizontal line.
Now I'm going to be bombarded by people telling me this is wrooong!
Trending Topics
05-03-2002, 10:20 PM
#8
Advanced
Join Date: Jan 2002
Location: Melbourne Australia
Posts: 98
Likes: 0
Received 0 Likes
on
0 Posts
Dear I3sI13
I would not suggest that you are wrong, but why suggest to only fill the oil until the oil gague is just over horizontal? Why not fill the oil until the guage at idle speed (with engine at normal operating temperature) is showing full or at or about the full mark?
That seems to me to be appropriate. If to correct measure is as you say then wouldn't it be logically correct to say that Porsche designed a gague where to fill with oil anything more than just slightly over horizontal would be to overfil the engine with oil?
Don't get me wrong, I'm just seeking some clarification for your suggestion.
Regards
Stephen Smith
93 C2 Tip
I would not suggest that you are wrong, but why suggest to only fill the oil until the oil gague is just over horizontal? Why not fill the oil until the guage at idle speed (with engine at normal operating temperature) is showing full or at or about the full mark?
That seems to me to be appropriate. If to correct measure is as you say then wouldn't it be logically correct to say that Porsche designed a gague where to fill with oil anything more than just slightly over horizontal would be to overfil the engine with oil?
Don't get me wrong, I'm just seeking some clarification for your suggestion.
Regards
Stephen Smith
93 C2 Tip
05-04-2002, 03:27 AM
#9
Addict
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Guys,
The oil level indicator is not telling you how much oil is in the engine, it is telling you how much oil is in the oil tank. Oil tanks do actually vary in size. You cannot measure the amount of oil inside a dry sumped engine.
The indicator pointer needs only 1 litre to go from the red to full.
There are no rules either because every 964 is different.
You do not fill the oil to the oil level indicator, you fill it to the dipstick. The best position to have the oil tank oil level showing is around the 3/4 mark. However the level of the ground, the actual idle speed, engine and oil temperature (yes they are different but you cannot see the oil temp because it is measureed at the oil cooler) are all variables which differ from 964 to 964. Condtion of the oil level sender and state of the oil tank itself also play a role. Just changing the oil lines (yes they do rust out) can change things slightly.
The "general rule" is to fill the engine with no more than 8 litres ( I use 6 litres) after an oil change (there are 2 litres you cannot get out), run the engine to get everything up to normal operating temp, then top the oil off using the dipstick.
The 964 is "Very" easy to overfill with oil and this leads to blowing smoke at start up to contaminating your airflow sensor which causes fluctating idle speeds which thenin turn messes up your oil tank level readings anyway.
The best way is at your next oil change. Record what is on the dipstick before you dump the oil. Dump the oil and measure how much oil you remove. This will help you determine the oil capacity of your own 964.
For the record, my 964 blew smoke yesterday. It had sat for over two weeks without being run. This is quite normal. The smoke blowing will not normally last too long. Blowing smoke after an oil change done exactly to the book is also quite normal. Most mechanics who follow the general specs overfill by half to one litre.
Ciao,
Adrian
911C4
The oil level indicator is not telling you how much oil is in the engine, it is telling you how much oil is in the oil tank. Oil tanks do actually vary in size. You cannot measure the amount of oil inside a dry sumped engine.
The indicator pointer needs only 1 litre to go from the red to full.
There are no rules either because every 964 is different.
You do not fill the oil to the oil level indicator, you fill it to the dipstick. The best position to have the oil tank oil level showing is around the 3/4 mark. However the level of the ground, the actual idle speed, engine and oil temperature (yes they are different but you cannot see the oil temp because it is measureed at the oil cooler) are all variables which differ from 964 to 964. Condtion of the oil level sender and state of the oil tank itself also play a role. Just changing the oil lines (yes they do rust out) can change things slightly.
The "general rule" is to fill the engine with no more than 8 litres ( I use 6 litres) after an oil change (there are 2 litres you cannot get out), run the engine to get everything up to normal operating temp, then top the oil off using the dipstick.
The 964 is "Very" easy to overfill with oil and this leads to blowing smoke at start up to contaminating your airflow sensor which causes fluctating idle speeds which thenin turn messes up your oil tank level readings anyway.
The best way is at your next oil change. Record what is on the dipstick before you dump the oil. Dump the oil and measure how much oil you remove. This will help you determine the oil capacity of your own 964.
For the record, my 964 blew smoke yesterday. It had sat for over two weeks without being run. This is quite normal. The smoke blowing will not normally last too long. Blowing smoke after an oil change done exactly to the book is also quite normal. Most mechanics who follow the general specs overfill by half to one litre.
Ciao,
Adrian
911C4
The following users liked this post:
nabfa1 (09-02-2023)
05-04-2002, 05:31 AM
#10
Race Car
I gotta admit, I have always used the gauge as a reference. I have checked the dipstick ONCE, in my SC, years ago...I don't even know if my 964 has one! 
I like to take the gauge to the first mark after the "LOW" zone, at maximum, the 3 O'clock position when the engine is HOT.
I have found this to be a very reliable procedure over the years, but then again, that's how I do it. I had a sender go bad in my SC, but then it was obvious when it went South, it read "FULL" even when engine was cold...replaced the sender unit and all was okay again.
I would NEVER recommend to fill the oil until you are in the RED - from my experiences...this is too full! Evident from overflow on the garage floor and in the airbox/throttle body...didn't want to mention all over the back of the car!! <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />
This is just my two cents, take it or leave it...but I LIVE by it...and put some VERY HARD miles on my car n the meantime - with NO engine failure.
I like to take the gauge to the first mark after the "LOW" zone, at maximum, the 3 O'clock position when the engine is HOT.
I have found this to be a very reliable procedure over the years, but then again, that's how I do it. I had a sender go bad in my SC, but then it was obvious when it went South, it read "FULL" even when engine was cold...replaced the sender unit and all was okay again.
I would NEVER recommend to fill the oil until you are in the RED - from my experiences...this is too full! Evident from overflow on the garage floor and in the airbox/throttle body...didn't want to mention all over the back of the car!! <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />
This is just my two cents, take it or leave it...but I LIVE by it...and put some VERY HARD miles on my car n the meantime - with NO engine failure.
05-04-2002, 11:57 AM
#11
Addict
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Dear Jeff,
I am as basically casual about checking the oil as you are. I know my oil consumption is 1 litre per 15,000km. I have no oil leaks and I use the oil level indicator as well. However everything I do is based on personal experience and testing. Often called playing around. The fact is the 3.6l engine can run down to around 8 litres maybe even as low as 6 litres before you even get a pressure light when the engine is hot. Low oil quantity can actually be heard in a 964 because it gurgles in the oil cooler lines and in the oil tank. You will also notice an increase in engine temp as the oil quantity reduces. I posted about this before. However there are some people who want the correct and accurate method and wish to be precise about the oil level and checking it. I understand this and my post was for those people. The other reason was to make 100% clear that oil quantity measurement is of the oil tank not the engine itself as in a wet sumped engine that most people are familar with.
Ciao,
Adrian
911C4
I am as basically casual about checking the oil as you are. I know my oil consumption is 1 litre per 15,000km. I have no oil leaks and I use the oil level indicator as well. However everything I do is based on personal experience and testing. Often called playing around. The fact is the 3.6l engine can run down to around 8 litres maybe even as low as 6 litres before you even get a pressure light when the engine is hot. Low oil quantity can actually be heard in a 964 because it gurgles in the oil cooler lines and in the oil tank. You will also notice an increase in engine temp as the oil quantity reduces. I posted about this before. However there are some people who want the correct and accurate method and wish to be precise about the oil level and checking it. I understand this and my post was for those people. The other reason was to make 100% clear that oil quantity measurement is of the oil tank not the engine itself as in a wet sumped engine that most people are familar with.
Ciao,
Adrian
911C4
The following users liked this post:
nabfa1 (09-02-2023)
05-04-2002, 10:55 PM
#12
Advanced
Join Date: Jan 2002
Location: Melbourne Australia
Posts: 98
Likes: 0
Received 0 Likes
on
0 Posts
Dear Moderators
I would like to be crystal clear about this oil level measurement issue.
Upon the assumption of correct functioning, the oil level guage in the dash (when the engine is idling @ recomended rpm at normal operating temperature, with 964 on a level surface) measures the oil level in the oil tank, which is also the precise measurement in determining whether or not there is the appropriate amount of oil in the vehicle?
The dipstick also under identical conditions (idle, temp, level) measures the level of oil in the oil tank, which again is the appropriate measure in determining whether or not there is the correct amount of oil in the vehicle?
Kindly advised
Thank you
Stephen Smith
93 C2 Tip <img src="graemlins/icon107.gif" border="0" alt="[icon107]" />
I would like to be crystal clear about this oil level measurement issue.
Upon the assumption of correct functioning, the oil level guage in the dash (when the engine is idling @ recomended rpm at normal operating temperature, with 964 on a level surface) measures the oil level in the oil tank, which is also the precise measurement in determining whether or not there is the appropriate amount of oil in the vehicle?
The dipstick also under identical conditions (idle, temp, level) measures the level of oil in the oil tank, which again is the appropriate measure in determining whether or not there is the correct amount of oil in the vehicle?
Kindly advised
Thank you
Stephen Smith
93 C2 Tip <img src="graemlins/icon107.gif" border="0" alt="[icon107]" />
05-05-2002, 12:42 AM
#13
Addict
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Dear Stephen,
Yes both methods measure the level of oil in the oil tank. Because the oil level sender is an electro-mechanical device I would not regard it as precise as the dipstick. However it is generally fairly accurate. You have to remember that these autos are now many years old and these type of devices age. The indicator itself degrades with age. The dipstick doesn't.
You also should understand that each 964 engine has what we call in the business (those who work with dry sumped engines for living), its own natural oil level. Some engines will seem to use oil and then just stop and maintain a certain level. This is quite normal.
Ciao,
Adrian
911C4
Yes both methods measure the level of oil in the oil tank. Because the oil level sender is an electro-mechanical device I would not regard it as precise as the dipstick. However it is generally fairly accurate. You have to remember that these autos are now many years old and these type of devices age. The indicator itself degrades with age. The dipstick doesn't.
You also should understand that each 964 engine has what we call in the business (those who work with dry sumped engines for living), its own natural oil level. Some engines will seem to use oil and then just stop and maintain a certain level. This is quite normal.
Ciao,
Adrian
911C4
05-05-2002, 06:46 PM
#14
[QUOTE]Originally posted by Adrian:
Some engines will seem to use oil and then just stop and maintain a certain level.
Exactly what mine does. If I fill to upper level it uses the oil quickly until it's down to the 1/4 level then does not use much at all (stays at this level).
Took a while to find this out and thought it used a lot of oil. I was forever filling it up but now maintain the 1/2 to 1/4 full.
Richard 1990 C2
Some engines will seem to use oil and then just stop and maintain a certain level.
Exactly what mine does. If I fill to upper level it uses the oil quickly until it's down to the 1/4 level then does not use much at all (stays at this level).
Took a while to find this out and thought it used a lot of oil. I was forever filling it up but now maintain the 1/2 to 1/4 full.
Richard 1990 C2
05-08-2002, 04:54 AM
#15
Racer
Join Date: Jun 2001
Location: USA
Posts: 391
Likes: 0
Received 0 Likes
on
0 Posts
Mine too. It seems to like to eat up a quart if I put one in to get the guage back up. I also notice a bit more oil on the garage floor than usual. But there it will stay for quite some time, until I get the urge to feed it again. Weird but true. The moral of the story I guess is as Adrian points out: Each car has its own characteristics, so best to pay attention to your car and learn its quirks. I myself, happen to use the guage, with the dip stick as backup. I can pretty much predict with quite amazing accuracy what the dip stick will show simply by noting the positions of the oil temp needle and the oil level needle on the respective guages. YMMV.