IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: Joel Russo on November 09 2014, 07:12:48 AM
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Had the car out for a run yesterday, couldn't resist a sunny 45* day. When I returned home, I pulled on the driveway...let it idle.... while I moved a few bicycles from in front of the GN stall door..
As I walked toward the car, I noticed "smoke" coming out of the exhaust. Looked to be typical bluish in color and had the smell of burning oil. I checked temp gauge and it was 165*, which is where it was while I was out for the run. I blipped the throttle and the smoke briefly went away until in came back to idle rpm, and then it came out of the exhaust again.
I did not notice it while driving or stopping while I was out on the road, but then again, I wasn't looking for it.
Stock unopened '87 GN with 14k on the clock..
Do I need to replace valve seals, or do I have a issue somewhere else?
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That is a definite "maybe"
I would start by checking for oil in the pipe to the throttlebody from the intercooler in case the turbo seal is leaking. Also I would like to assume you have replaced the tube from the end of the valve cover to the turbo inlet with a small KN filter plugged into the end of the valve cover and capped off the inlet to the turbo. You might also check to see if the pcv valve rattles when you shake it up and down to be sure it is not stuck open.
You could also do a leak down check to make sure the rings are not worn out and you are sucking blow by thru the engine and out the exhaust.
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I have a small KN filter on the end of the valve cover, and capped the inlet to the turbo.
The PVC valve rattles when I shake it.
I removed the up pipe from the intercooler, and it was relatively dry. I rubbed my finger in it to show that there is a bit of oil build up. See pic.
The throttle body is completely dry. See pic.
Won't be able to do the leak down until later in the week.
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I had a turbo oil leak that only leaked into the exhaust side and not the compressor side.
I would find it hard to believe you have bad rings on a 14k mile original engine. Was the PCV full of oil?
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PCV was clean.
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My money is on turbo seal.
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My money is on turbo seal.
How do I check that?
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Like Steve said, oil in the up pipe. There should be zero. Take the pipe from the maf off the turbo and see if there is any back and forth movement of the turbo wheel. If it moves the turbo is probably pushing oil into motor.
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he checked the compressor side...so it's pull the downpipe off and see if there is any oil in the exhaust housing side.
After 27 years or so, the factory seals could easily be dried and failing...I was trying to eliminate the easy before popping springs off
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I'll pull the downpipe off this week and report back...
Thanks gents.
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I just pulled the downpipe and it's bone dry....
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How much oil is it using? any of the plugs showing any carbon from oil?
If it was me I would decide if the oil consumption was too bad. If very little lost between oil changes I would ignore it and just enjoy the car.
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I suppose there is a possibility of leaking seal on the intake side of the turbo...
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Had the same problem. Turned out to be the turbo seal. It is possible for the turbo to be bad without showing signs of of oil on hot or cold side.
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X2 on a turbo exhaust side leak and didn't show any obvious signs looking at the exhaust whee, l or in the downpipe.
it's probably going to show signs there eventually if you keep running it of course,
may also check valve seals if nobody has mentioned those yet
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He never answered how much oil it was using and if he checked the plugs for signs of carbon. If it is consuming a significant amount of oil and the plugs are clean it is just another sign pointing to the turbo leaking into exhaust.
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With only about 6k miles on the turbo, I'm figuring on the valve seals....
It's resting in the heated garage until we get through the winter.
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He never answered how much oil it was using and if he checked the plugs for signs of carbon. If it is consuming a significant amount of oil and the plugs are clean it is just another sign pointing to the turbo leaking into exhaust.
There is no oil consumption.
I'll pull a few plugs tomorrow and see what they look like.
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He never answered how much oil it was using and if he checked the plugs for signs of carbon. If it is consuming a significant amount of oil and the plugs are clean it is just another sign pointing to the turbo leaking into exhaust.
There is no oil consumption.
I'll pull a few plugs tomorrow and see what they look like.
If there is no oil consumption then you are not burning any oil. :rofl: (I am just being a smart ass, I am assuming you mean no significant oil consumption).
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If there is no oil consumption then you are not burning any oil. :rofl: (I am just being a smart ass, I am assuming you mean no significant oil consumption).
Hey, I'm used to it, I have kids.... :cheers:
No significant oil consumption.
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You might not see anything on the plugs then but still worth checking them.
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With only about 6k miles on the turbo, I'm figuring on the valve seals....
It's resting in the heated garage until we get through the winter.
Mileage on the turbo is not a reliable way to rule it out. I bought a turbo with 0 miles on it rebuilt by a very well known shop. 400 miles later it started smoking. This time sent it to bison to be updated. No problems since. Like you, I initially thought valve seals but came across a thread by Nick Micale that suggested it wasn't the likely cause. Before you start looking for a problem that doesn't exist I would simply swap the turbo with a known good one to rule it out.
Does your car start smoking only after it warms up (as opposed to immediately after start up) and most noticeable at idle? It only takes a small amount of oil to produce smoke. Mine was leaking a tiny bit on the exhaust side but not enough to see it when I pulled the DP. Most times it only smoked after I let it idle a few minutes and after the exhaust got hot enough to burn the oil, producing smoke. If you're lucky you might be able to see some wetness if you shine a light and take a peek behind the exhaust wheel. Good luck in sorting out your problem.
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In case you were interested, I pasted my post on the other board below when I was going through my smoking problem. I'm not saying your valve seals are not the problem. I'm just saying you should first rule out the turbo, in a definitive way (not just visual), before you dig deeper into the motor. Have you checked the thrust yet? Anyway, hope this helps.
"Correct, I already looked in the usual areas and replaced the PCV. PM'd bison and he confirmed it is possible for the turbo to smoke eventhough I could not find visible oil in the exhaust side of the turbo.
I also did a search on valve seals thinking this may be the problem and came across a post by Nick saying:
"In all the stock valve spring replacement jobs I have done, not once have the seals been replaced. If there is an issue with the valves or seals, the heads need to come off for repair.
I have seen many GN's with over 150K miles that are fine with original seals. So maybe a little oil will go through the stems, that can be a good thing to minimize guide wear.
When we do a performance valve job, that is a different story. The guides have bronze inserts installed, and are machined for PC type vs. o-ring seals.
I am very fortunate to have a GN owner as a friend and fellow racer who has been racing for years with one of his cars that has been 10.9 on the original, unopened engine. I continually use his car as an example of how good the original engine will perform with minimal internal work or changes, and how important it is to have the proper supporting parts.
The heads have NEVER been removed on this GN with over 700 track passes, and internally all that has been done is replacing the timing chain set and the valve springs also - but NOT the oil seals! (http://www.turbobuick.com/forums/styles/default/xenforo/clear.png)
But I could be taking his statement out of context as the subject of that thread had nothing to do with a smoking problem...That said, it still doesn't mean my valve seals are ok. Whats the best way to find out?"