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Any luck with snake oils?


Los_Control

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Working on my off topic sbc chevy 350 today. And I have a mystery to solve.

I want to ask if any of you great people here come across a situation like this

First off, the motor runs awesome and does not burn oil. You can be rolling 30 mph and goose it just by accident ant and break the tires loose.

Just saying, the motor is in good condition. When I bought the truck, it had been sitting for awhile and was sold as a driving project.

The exhaust tip was light brown. I knew that motor was running right, one of the reasons I bought it.

 

I probably have 6k miles on it in 2 years, and have changed the oil 3 or 4 times ... just trying to flush the engine. Also changed all the other fluids.

The issue I am now facing, if I let it sit and idle for long periods, it starts to burn oil and smoke. If I stop for a red light, is a non issue.

If I run into a traffic stop on the freeway because of road construction, then it will start burning oil. Get past the construction and within 1 mile it no longer smokes.

Until the next time you let it idle for extended periods.

 

The only info I can find on this problem, either a clogged pvc system, or sludge built up in the motor and clogging the return ports in the heads.

Causing overflow and burning out through the cylinders.

I am open to suggestions, right now I am guessing the frequent oil changes has knocked sludge loose and clogged the return ports.

 

Now I am thinking to try seafoam or marvel mystery oil in the oil and do a 5th oil change. I have both on the shelf just wondering which one to try.

 

So my question is, if I do have sludge blocking oil ports, which product would work better?

Or does anyone with past experience have a opinion on what to do with this issue?

 

I remember when I was a kid working at the gas station, I mixed atf in with motor oil and cleaned up a sludge'd up engine. 

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It only takes a minute to pull the valve covers and check the oil return holes if you really think that's what's causing the problem I think it's probably sucking oil through the exhaust valve seals. They're easy enough to change without a teardown. You can get an air fitting to screw in the spark plug hole and then use a spring compressor to remove the valve spring. Chevy used an o-ring type seal but there are umbrella seals available. I don't think much of SeaFoam, Marvel Mystery Oil, fuel system cleaner, really anything along those lines. Maybe it's just me.. ?

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59 minutes ago, MackTheFinger said:

It only takes a minute to pull the valve covers and check the oil return holes if you really think that's what's causing the problem I think it's probably sucking oil through the exhaust valve seals. They're easy enough to change without a teardown. You can get an air fitting to screw in the spark plug hole and then use a spring compressor to remove the valve spring. Chevy used an o-ring type seal but there are umbrella seals available. I don't think much of SeaFoam, Marvel Mystery Oil, fuel system cleaner, really anything along those lines. Maybe it's just me.. ?

 

43 minutes ago, Plymouthy Adams said:

valve stem seals

 

Looks like a bigger job ahead. Just thinking about my older 327 chevy and the valve seals were always bad. You start the motor in the morning and puff out blue smoke.

This motor never smokes, except when sitting for long idle. I do not mind doing the work ... just trying to figure out in my mind what exactly is going on before I tear it down and work on it.

Then make the best choice on a repair.

 

Not even sure what motor I have, it is a 350.  I need to check the numbers.  The rear end and trans is from a 2004 or newer, I suspect engine came from the same truck.

Now I am thinking that the drivetrain has been changed, which means a newer motor with the older throttle body intake installed.

And I have to double check tomorrow if they plumbed the pcv in correctly?

In another forum, the possibilities  are.

Pcv stuck
Plumbed in wrong
Intake manifold leak
Vacuum leak

 

I am starting to wonder if maybe a mis match of parts making pcv inefective.

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I think you are on the right track with troubleshooting the PCV system first based on your described symptom.  If you had valve stem seals going bad or other internal engine issues I would expect to always have the oil burning, not just when idling for long periods of time.  

 

High manifold vacuum at idle is supposed to keep the the PCV mostly closed to flow.  In your case it seems something is keeping the PCV open to flow when you are in that condition.  Most common is of course vacuum leaks or stuck PCV.  You should also check the PCV ventilation; if it's clogged or insufficient it can cause high crankcase pressure that will also exhibit this symptom.  

 

As far as the "snake oils."  I would read the MSDS/PDS for the products in question before I used them for engine cleaning.  Most of them are comprised of light oils, some solvents and something to make them smell distinct.  I think MMO is stoddard solvent and wintergreen or something like that.  Will it help with cleaning sludge?  A little bit perhaps, but at the cost of lubrication effectiveness.  Would you pour a pint of paint thinner into your oil?   That's  sort of what you would be doing.  Many people swear by it, but I am not convinced.

The best bet is drop the pans and manually remove any sludge, then fix the root cause of the sludge. With unleaded gas and modern motor oils, sludge is fairly rare unless the PCV system isn't working right or oil change intervals are virtually non-existent.

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I think one should read a white paper on the valve stem seals and when they are most likely to show their ugly side when bad....if this engine also has the GM factory seals...they trash within 5000 miles if they last that long....they allow blow by at long idle periods, deceleration and often when shifting gears as the vacuum is highest at these times and often show puffs/wisps of oil consumption....while sustained speed at cruise and no feathering of the accelerator the vacuum is high also but with the very speed of the vehicle the disturbance a the exhaust will be so great it is not noticeable...smart GM owners use Mopar cup style valve seals...

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4 hours ago, MackTheFinger said:

if it's one with only 4 intake bolts per side you may very well have leaky intake manifold gaskets.

It does have only 4 bolts per side. I am leaning in this direction. Curios if there would be any obvious signs of the manifold leaking?

Seems to me it might act like a vacuum leak, or rough or high idle. I will have to do some searching on this.

Thank you for the help on this.

 

24 minutes ago, Old CWO said:

I think you are on the right track with troubleshooting the PCV system first based on your described symptom

I wish it was the pcv, would be a simple fix .... I usually do not get that lucky.

I replaced all the rubber hoses on the truck when I bought it, just a simple hose from the base of throttle body to pcv. I imagine it is correct routing.

Going in to town in a few and will pick up a new. Just checked the old one and it does move freely.

Thanks for suggestions

 

I think Mack may have nailed it with intake leak.

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4 minutes ago, Plymouthy Adams said:

smart GM owners use Mopar cup style valve seals...

:D sounds like a worthwhile mod.

I had cars in the past, chevy with bad valve seals. A tell tale sign was the puff of smoke every time  you started it when cold.

Also I am not using oil. If I drive it normal and no extended idle, stays right on the full mark. It will burn a quart real quick if I let it idle though.

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Easy way to check the PCV suspicion:  just remove the hose from the manifold and plug, if the idle smoke goes away, you've nailed it.  Be aware that the idle will change when you do that since it will be richer, how much depends on the PCV valve.

 

I didn't see the year of your truck, but another suspect, only if your truck/transmission has a vacuum modulator, they can cause smoking when failed.  Using any trans fluid?

 

Also, the PCV system includes baffles inside the engine, valve cover or intake depending on year, that help seperate the oil splash/vapor from the PCV flow.  A wrong mix of parts could do that tool.

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I doubt that six bolt intake is causing your problem. How do the plugs look? SBC's are notorious for sucking oil and fouling plugs. I've seen more than a few with one or more hotter plugs to deal with it. 

 

If you can't find the Mopar valve seals PA recommended or if they don't work you could try FoMoCo seals.  ?

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Not sure what to think now ...  I made a couple short vids just to show what I am seeing.

This vid I did not rev it up, but it is not smoking, I could rev it up and still not smoke.

The last time I seen it smoke before today, was a few months ago when I got stuck in road construction.

 

 

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Then today, because I let it idle in the driveway, you can see I could rent myself out for mosquito control.

As long as I dont let it idle, it never smokes ... let it idle and it is pumping oil quickly into the cylinders.

I think the smoke may be to much for just leaky valve seals ... I could be wrong though, if one completely failed.

I now just need to take it out on the freeway for a short time, will clear the motor and I will not see any more smoke, until I let it sit and idle again.

 

With it smoking as it is, I pulled the new pvc and was watching for blow by,  There was a very small amount.

But because of the extra oil in the cylinders burning at the moment ... ???? I need to take it on the freeway and clear the motor, then check for blow by again.

At this point, kinda thinking to pull the intake, then the heads at the same time and have a machine shop go through them. .... assuming no blow by when it is cleared up.

The amount of blow by at this time is hardly detectable, does not increase with throttle response.

1 hour ago, MackTheFinger said:

If you can't find the Mopar valve seals PA recommended or if they don't work you could try FoMoCo seals.  ?

I wonder what the machine shop will suggest?  :D

 

 

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If you take the heads to a machine shop, I'd recommend cutting the guides for positive seals.  I've used PC in the past with success.

 

But, the thing is this:  there is more oil up there in a Chevy at cruise speed, not idle.  So, bad seals will usually cause smoke when decelerating from speed, closed throttle, high vacuum and leftover oil from the speed.  That, and smoke at startup.  If it does neither of these?????

 

When you had the PCV out, did you plug the valve and see what happened?

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13 hours ago, kencombs said:

When you had the PCV out, did you plug the valve and see what happened?

 

 

I should have but did not, a new one cost $1.99, and if it cured it would know ...

I also wanted to show a short vid, why I am not thinking valve seals.

While being concerned with the pvc side, I have not checked the other valve cover. Looked at it this morning.

It has a straight tube with no valve coming out of the valve cover and connects to the top of the throttle body.

This hose is full of oil. I assume it may be my issue.

In my twisted thinking, I would think that hose to connect to the air cleaner housing, not below the air cleaner.

If this is correct, then possible I have the wrong valve cover with no baffle?

It should have a pcv installed?  I never seen a car with 2 pcv.

 

But I think I am going to run it out on the freeway to clear it out, plug the throttle body hose and try again.

 

 

0925190915.jpg

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7 minutes ago, Merle Coggins said:

That may be designed to be the fresh, filtered, air inlet into the crankcase to replace the air scavenged out by the PCV system. It's possible that you are drawing air back up through that hose, along with oil vapor. Could your air filter be getting plugged?

 

Merle's right, the normal installation for PCV is to bring filtered air into the engine, circulate to pick up the crankcase vapors, then through the valve to burn them.  That appears to be your inlet line and should not have a vacuum.  

 

Does the throttle body injector show signs of oil being drawn in in that area?  If so, he may also be right about a very restricted air filter.

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27 minutes ago, Merle Coggins said:

Could your air filter be getting plugged?

That is a good question, and it brings up a bit of a mystery.

My first thought is no, it looks like it is brand new

 

Now the question is, why does it look brand new?

That air filter is close to 2 years old, looks like I just pulled it out of the box. With the amount of miles I drive, not a lot but several road trips. There should be at least a little bit of dirt on it.

There is not a spec of dirt anywhere on it. There should be some.

A second photo shows the air cleaner housing, how it connects into the fender and has a duct system to the front grill area, I wonder if this is clogged?

And causing the issue?

 

 

 

IMG_20190925_110150996.jpg

IMG_20190925_105702200.jpg

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And for a quick test, I can already tell a difference. Will it solve it? I dunno.

With it idle in front of the garage, it was real rich and gas you out, I have to turn on the fan and pull fresh air in.

Running as it is now, I do not need the fan to clear the air.

 

But not able to drive it on the freeway to clean it out yet, I need to fix the horn issue I created when I fixed the turn signals  ?

But letting it idle in the driveway should clean it out if that really is the cause.

 

 

IMG_20190925_113404261.jpg

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I pulled the steering wheel back off and replaced the horn thingy, took the dog for a drive.

Got home and let it idle some, issue came back .... I really think that a engine is a air pump, and obvious my air pump was not getting correct air intake.

 

Trying to figure out in my mind what damage that would cause?

I am going to go ahead and add the mmo to the crank case, take it for a good drive 45 min ...  Fill the gas tank and add the sea foam there.GTX 10/40  come home and change it while it is hot.

Then I will have my own opinion about the snake oil.

 

Still scratching my head and wonder how this thing even ran.

Makes sense, it had been parked in a storage shed for over 2 years when I bought it. Why the exhaust was coco brown when I bought it.

But while stored, rodents moved in and clogged the air delivery system.

What I do not understand, how it ran so good when it was not getting proper air delivery.

The truck is not special or a built engine, but it is a challenge to keep from spinning the tires in 1st gear,  The next goal is to not spin or chirp them when hitting second gear. The chirp is just to easy and happens often.(I paid $550 for these tires, want them to last)  It cruises at 80 mph in 5th gear just barely touching the gas.

 

It may just clear itself out with some drive time, since I already have the products and 1.5 quarts low on oil, going to try them any ways.

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When my son rebuilt DC Pete  we took the duel exhaust off and stuck it up above the rafters in the shed. All in one piece with the mufflers. Three years later we put the motor back in, hooked up the exhaust and had my buddy come over to help me get it started. Once it started, it started to shoot dog food out of the exhaust like bullets. I’m assuming mice were stealing my dogs dog food and caring it up 2 story’s to keep for a rainy day. Ambitious little buggers. 

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On 9/25/2019 at 2:44 PM, Los_Control said:

 

It may just clear itself out with some drive time, since I already have the products and 1.5 quarts low on oil, going to try them any ways.

 

Let us know what happens. Many years ago I had a '68 C-10 I bought without an engine. I then bought a 283 from a kid that lived nearby. Put a WCFB and a set of Hooker headers on it. It was a great running motor but used a quart of oil every 50 miles! I assumed it needed a total rebuild and sold it fairly quickly.

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3 minutes ago, MackTheFinger said:

 

Let us know what happens. Many years ago I had a '68 C-10 I bought without an engine. I then bought a 283 from a kid that lived nearby. Put a WCFB and a set of Hooker headers on it. It was a great running motor but used a quart of oil every 50 miles! I assumed it needed a total rebuild and sold it fairly quickly.

It will take a bit of time to really tell. Driven it as much as I can the past few days. Friday it was still putting out a few wisp of smoke, I was thinking that it probably does have bad valve seals at this point. Was going to report back that info. But then today and Saturday, I hot rodded it around a bit and can not see any smoke again. Watching at the first start in the morning, nothing ... rolling down the highway and just nail it to the floor, nothing.The oil looks nice and clean.

 

This is normal for this truck in the past, the only time it would smoke is at extended idle. Then a day or so of normal driving and clear back up.

I honestly was confused as what was causing it.

The only test left to do, is let it sit and idle and see if it starts smoking again .... Jeez I am such a chicken   :P  It runs fine as is leave it alone.

Going to give it a week or so, clean the fresh air return line out and then try again.

I just have no clue what permanent damage could be caused from running the motor that way.

 

 

Got a few 4 hour road trips coming up, minor medical procedure for the wife, tomorrow we take her car for the AC, next month be taking the truck.

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1 hour ago, Los_Control said:

 

The only test left to do, is let it sit and idle and see if it starts smoking again .... Jeez I am such a chicken   :P  It runs fine as is leave it alone.

 

 

 

Got a few 4 hour road trips coming up, minor medical procedure for the wife, tomorrow we take her car for the AC, next month be taking the truck.

 

I agree, if it's running okay and not fouling plugs or blowing a bunch of smoke I'd keep going! Hope all is well with the wife! 

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