White smoke coming from the dipstick and oil cap (Page 1/2)
FieroInFlames MAR 28, 04:33 PM
https://imgur.com/gallery/FNes0jt

Not sure what to do or where to start. Car runs fine, starts up right away, and I don't feel like there's any loss of power. Had some suggestions from the subreddit that it's a bad exhaust mainfold gasket, a valve cover leak, or blow by. Can anyone help me diagnose the problem? I attached an imgur link at the top with a video of the engine smoking.
skywurz MAR 28, 04:36 PM
I am going to say run a compression test. That looks like all sorts of head gasket to me.
FieroInFlames MAR 28, 04:42 PM

quote
Originally posted by skywurz:

I am going to say run a compression test. That looks like all sorts of head gasket to me.



I can find people discussing the results of their compression tests all over the internet, but I can't find a guide on it. Would it be in the haynes manual and do a need that little gauge thing actually do it?
skywurz MAR 28, 04:52 PM
You need the guage. If it's a small leak you may not detect it with this method. I suspect you have a combustion chamber to oil jacket leak. The smoke you see is exhaust entering the oil jacket side of the engine. When this happens on the coolant side you can do a leak down test to confirm.

Edit:

I think you are experiencing #2 in this list
https://haynes.com/en-us/ti...head-gasket-can-fail
I've personally seen and worked on 5 out of 7 in that list. I've yet to see oil or coolant to outside.. but probably will eventually.

[This message has been edited by skywurz (edited 03-28-2021).]

Dennis LaGrua MAR 28, 05:10 PM
Might be a good idea to also pressurize the cooling system. If it doesn't hold pressure then its most likely a head gasket problem. White smoke is usually steam.

------------------
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Patrick MAR 28, 06:05 PM

quote
Originally posted by FieroInFlames:

I attached an imgur link at the top with a video of the engine smoking.



That's gotta be one of the crappiest ways of posting a video. First, shoot video in the correct orientation, not in portrait/vertical video mode. Then upload it to YouTube, where you then can easily embed the videos in your posts here.

In regards to your issue, check that the PCV system is operating properly. Otherwise, pressure in the crankcase builds up and it tries to escape anywhere it can. Make sure the PCV valve isn't sticking, or better yet, just replace the valve. It's inexpensive.

[This message has been edited by Patrick (edited 03-28-2021).]

skywurz MAR 28, 06:42 PM

quote
Originally posted by Patrick:

That's gotta be one of the crappiest ways of posting a video. First, shoot video in the correct orientation, not in portrait/vertical video mode. Then upload it to YouTube, where you then can easily embed the videos in your posts here.

In regards to your issue, check that the PCV system is operating properly. Otherwise, pressure in the crankcase builds up and it tries to escape anywhere it can. Make sure the PCV valve isn't sticking, or better yet, just replace the valve. It's inexpensive.




The only reason I disagree with PVC is from a different video he didn't share here where there's smoke puffing out of the dipstick tube with the dipstick still installed. (He said he posted in Reddit and thought id see what advice he got over there i did this before my initial comment)

WARNING! Portrait Video
https://www.reddit.com/r/fi...l_me_this_is_normal/


Edit:

Also this rear line that has no check valve and is under constant vacuum while running.

[This message has been edited by skywurz (edited 03-28-2021).]

Patrick MAR 28, 07:29 PM

quote
Originally posted by skywurz:

The only reason I disagree with PVC is...



I disagree with PVC as well... because it's PCV.


quote
Originally posted by skywurz:

Also this rear line that has no check valve and is under constant vacuum while running.

CLICK FOR FULL SIZE




That tube is the air supply for the PCV system. If the PCV valve isn't stuck shut, yes, that tube is normally under vacuum. However, under certain engine conditions, crankcase pressure is temporarily forced to go the other way (into the air snorkel)... and if the PCV valve is stuck shut, then built up crankcase pressure is constantly being pushed out into the snorkel... and out anywhere else it can escape.
skywurz MAR 28, 08:33 PM

quote
Originally posted by Patrick:

That tube is the air supply for the PCV system. If the PCV valve isn't stuck shut, yes, that tube is normally under vacuum. However, under certain engine conditions, crankcase pressure is temporarily forced to go the other way (into the air snorkel)... and if the PCV valve is stuck shut, then built up crankcase pressure is constantly being pushed out into the snorkel... and out anywhere else it can escape.



HA! I blame autocorrect

I guess I had my vacuum direction swapped and found this nice video.

[This message has been edited by skywurz (edited 03-28-2021).]

Patrick MAR 28, 09:23 PM

quote
Originally posted by skywurz:

...found this nice video.



Yeah, that explains it pretty good. I first learned about the PCV system back in the early 70's while fiddling around with small and big block Chevy engines. Pretty simple, yet effective system which hasn't changed much over the decades.