When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I need advice . my truck smokes at idle after 4-5 of running .some times it may take longer to see blue smoke.
my puzzle is .iF i start and drive it never smokes or if bring to a fat idle like 2000 while its smoking it will quit .
history engine only has 6000 miles since built
i have changed return hose ,added a nice catch can .I was thinking valve seals or guides .i called precision turbo .They said if had bad seal it would smoke all the time .and he also said there turbo's have like a metal snap instead of seal and they never leak .truck does not smoke under boost or once it warms up to operating temperature .
THANKS
Valve guides, seals can cause that, a lot of times you get smoke on startup because of it. Also on like a turbo 400, 350, the modulator valve can go bad, suck oil, if your running one of those trans.
Valve guides, seals can cause that, a lot of times you get smoke on startup because of it. Also on like a turbo 400, 350, the modulator valve can go bad, suck oil, if your running one of those trans.
4l80e tranny also i pull valve cover and looked ,machine shop installed umbrella seals .not the ones held down by spring
The ID of fittings is usually considerably smaller as well. IF you look at the old manuals from garret and like turbos they suggest 3/4 to 1" ID. SS line is pretty bad about ID. And not all -10 lines have the same ID either. Sounds odd but I've always used 3/4 copper pipe fittings an tubing. Its cheap, available at any hardware store, heat resistant and I've never had a drain issue. Its a true 3/4 ID and the 45* fittings/ 90* etc are true 3/4 ID as well. Also the OD is not massive like a standard 3/4 rubber hose.
Some thin wall tubing style fittings and 3/4 high temp hose would be my second choice. I'd address the drain. It's where 90% of the smoking turbo issues come from. (assuming the turbo isn't ancient or damaged)
I think you should first determine if it's the engine or turbo that's the problem. Shut if off while smoking, disconnect charge and down pipe to see if oil is coming from the turbo. If not then it could easily be valve seals or possibly even rings (not likely) also could be PC system oil running into some cylinders from intake manifold. Really umbrella seals on an ls ? Used to go to some trouble to put positive seals on old school BBC/ SBC . The oil and carbon deposits it produces are bad for knock control. The stock style valve seal also is a spring seat/shim. Only reason I could see to not run them would be to save a few measly $$
just to clarify using ID as the OD can be all over the place - I think officially a -10AN ID is around 1/2"Aeroquip Starlite Racing Hose
AN Size ID
-04 0.22"
-06 0.34"
-08 0.44"
-10 0.56"
-12 0.69"
-16 0.88"
-20 1.13"
Measure the diameter of the drain hole on the turbo. Your drain should be that ID at minimum the entire run. The more bends and the poorer the drain angle, the larger the drain should be.
For example... If you have a 20mm drain, -10 or even a -12 isn't going to cut it.
Last edited by Forcefed86; Jun 29, 2020 at 08:25 AM.
this should be the first step IMHO. I am betting it’s the oil drainage problem. But I don’t know **** about turbos stuff a(that’s why I’m here, learning)
Originally Posted by GMCGreg
I think you should first determine if it's the engine or turbo that's the problem. Shut if off while smoking, disconnect charge and down pipe to see if oil is coming from the turbo. If not then it could easily be valve seals or possibly even rings (not likely) also could be PC system oil running into some cylinders from intake manifold. Really umbrella seals on an ls ? Used to go to some trouble to put positive seals on old school BBC/ SBC . The oil and carbon deposits it produces are bad for knock control. The stock style valve seal also is a spring seat/shim. Only reason I could see to not run them would be to save a few measly $$
thanks to all .i have narrowed it down to drain . remove hose -10 measured only 1/2 inch. .BUT here is the problem the- 10an to npt threaded to oil pan . Only measured 1/2 on on the -10 side and tampered down to 3/8 on npt side . i removed it and drilled it out to 1/2 . started truck up 90% better . so i am redoing the drain 3/4 all the way .
thanks to all .i have narrowed it down to drain . remove hose -10 measured only 1/2 inch. .BUT here is the problem the- 10an to npt threaded to oil pan . Only measured 1/2 on on the -10 side and tampered down to 3/8 on npt side . i removed it and drilled it out to 1/2 . started truck up 90% better . so i am redoing the drain 3/4 all the way .
Nice man 👍. I recently became a big fan of 3/4 ID soft copper for my drains lol
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
Turbo smoke 6.0 
