Car smoking after oil change

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mcampbell26915

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Hi all, I recently changed the oil on my '72 302, I read online that Valvoline Vr1 10w30 racing oil is the best oil for these older cars because of the zinc content, but I couldnt find any of that oil locally so I went ahead and used STP 5w30 instead.  I read that that would be just fine to use in my car here in san antonio.  While changing the oil, I noticed a pretty decent transmission fluid leak unfortunately.  So after finishing the oil change I checked the transmission fluid level and it was a bit low.  I added some Lucas brand transmission stop slip to top off the transmission fluid and hoped that that would slow the leak down a bit. 

After finishing the oil and topping off the transmission fluid, I did a test drive and it ran just fine, however after a few minutes of driving it started to smoke- A LOT.  blueish white smoke came from everywhere once the car heated up; it came from the exhaust pipe, the engine bay, and even from the wheel wells.  I looked under the car to see how it could be coming from the wheel wells and discovered that there was a pretty big exhaust leak which was dumping out that smoke.  This car didnt smoke pretty much at all before I changed the oil and added the stop slip.  I did spill a bit of the stop slip when topping it off, so I did expect a bit of smoke from it burning off, but there is so much and its coming from the exhaust too so I know it cant just be that.  

After the car ran for a while and still was smoking with no sign of subsiding, I noticed a clicking noise from the engine- maybe lifters.  I decided to shut it off and post on here and figure out if you guys know what the heck happened.  

I am assuming (and hoping) that I was just given misinformation about the type of oil that would be ok for my car, and that replacing the 5w30 with the VR1 10w30 will somehow fix this issue. I read somewhere that adding too much oil can cause it to smoke because the pressure builds up too high and leaks into the cylinders and causes it to burn.  However, after I changed the oil I measured the exact amount I took out and then added the exact same amount back in (5.6 quarts). The dip stick is showing adequate oil levels too, so I wouldnt expect there to be too much.  

Hopefully one of you has had a similar issue and knows how to resolve this, Thank you!

Matt

 

waterlife

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The oil is too thin. When the car was new, 10/30 was nesseccary, but now I would use sae30 or 20-50 only. I just bought 20/50 vr1 off Amazon fyi.

 
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10-40 should be good unless way high mileage. All cars with flat tappets need the zinc. You can get the additive at parts store I use the Lucas. There is another oil company that still makes a high zinc oil and not just a racing oil. Odd name that I can never remember.

I use Havoline and have for years. I changed the oil in my Mach 1 after 37 years and started it yesterday. It smoked briefly where I had squirted WD-40 in the spark plug holes several weeks ago. It has Havoline 10-40 withe the Lucas zinc additive. Comes in a cardboard box in plastic bag now with 6 quarts.

I am not one of those that believes you need to change the oil with low miles once a year. It can be in there for 10 years it does not go bad.

I posted a video earlier of me driving the car into the Mustang museum and you can see no smoke at all.

 

midlife

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Did your car have some good sex earlier in the day? A good reason for smoking afterwards...

I agree: 5W-30 is waaaay too thin.

 

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Your transmission vacuum modulator diaphragm may be ruptured and sending trans fluid into your intake via the vacuum signal line.Hence the smoking. In any event 5w-30 is not appropriate.

 

mcampbell26915

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Thanks everyone for the replies!

Looks like the consensus is just that I used the wrong oil (how could I be so naive?) I will replace the oil with 20w50 VR1 when I get back from my trip next week.  Im sure that will clear up this mess, thanks again!

Matt

 
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IIRC Total for the 302 engine with a stock pan and filter is only 5 quarts. Overfilling can lead to some of the oil being sucked through the PCV system or overwhelming the valve guides. I'd drain off a half quart and try it again before changing the oil. I agree 5W 30 isn't a good match for the older engines but I think you overfilled as well (Unless you have an aftermarket pan)

BTW it won't hurt to run an engine with a little bit less than the recommended oil capacity. Drag racers often run a quart low to reduce windage and increase power. I don't recommend it on the street, but starting it and test driving it with a slight low level won't hurt a thing (Slightly low is still showing on the dipstick at 1 quart low or less.

 

Don C

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Jeff is correct, the total refill capacity should be 5 quarts, this includes what is needed for the filter. If you had that much oil in your crankcase I would try to find out why. The most likely reasons:

-Wrong dip stick, verify dipstick reading by changing oil and filter, add 5 quarts, run for a few minutes and check it after it has set for 5 minutes.

-Overfilled by checking oil too soon after shutting engine off (especially when cold), not giving oil time to drain into crankcase.

-Leaking diaphragm in fuel pump, pumping gas into crankcase, verify by smelling oil for gasoline odor.

-Missing on one or more cylinders, raw gas bypassing rings into crankcase, smell oil for gasoline odor.

-Head gasket leaking allowing coolant into crankcase, oil would have milky appearance when changed and on dipstick.

 
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I guess I did not notice the amount you put it.

They are very correct on too much oil being bad. If the crankshaft and rod ends are hitting the oil as it rotates can cause damage and also foam the oil.

I had a PCV valve actually get ice in it once and it sucked oil out looked like the engine blew. Was fine when I washed the PCV valve out. You might look at it. Shake it and see if the ball is free and wash with some brake / parts cleaner.

Don't ever do this but when we Kart raced in WKA in the box stock class which was 5 hp. Briggs engines we did some crazy things. You never put but half the amount in the crank case just like stated a full pan slows the engine down. If you needed just another tenth or two in qualifying you would drain all your oil out for the qualifying lap, lol, yes all. The engine would turn faster. You also pulled the seals out of the rear axle ball bearings and washed the thick grease out of there and sprayed WD-40 in. That also helped resistance.

 

Mister 4x4

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I was going to suggest that maybe there was too much oil in the crankcase, but I didn't want to make any assumptions or insult anybody.

I had a friend decide to change his own oil, not knowing anything about his car, he opened up the drain plug he found under the truck and emptied it... then added 5 quarts of oil to the OIL fill in the valve cover.

He'd actually drained his manual transmission, and added another 5 quarts to his crankcase - smoked like a chimney when he fired it up.  Once we dumped all the oil, then refilled both crankcase and transmission, everything was fine.

I'd recommend checking your fluid levels in both the transmission AND the crankcase just to make sure that's not the issue.

 

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I was going to suggest that maybe there was too much oil in the crankcase, but I didn't want to make any assumptions or insult anybody.

I had a friend decide to change his own oil, not knowing anything about his car, he opened up the drain plug he found under the truck and emptied it... then added 5 quarts of oil to the OIL fill in the valve cover.

He'd actually drained his manual transmission, and added another 5 quarts to his crankcase - smoked like a chimney when he fired it up.  Once we dumped all the oil, then refilled both crankcase and transmission, everything was fine.

I'd recommend checking your fluid levels in both the transmission AND the crankcase just to make sure that's not the issue.
Eric, Did you just make that up? lollerzChuck

 

mcampbell26915

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Thank you all for your feedback! I just got back from Europe, and changed the oil today to VR1 20w50. (5 quarts)

I drove the car around and after about 15 minutes it started to smoke again.  it didnt smoke quite as bad, but definitely still smoked a good amount.  I shut it down and waited 5 minutes and checked the oil level, which read around 4mm below the bottom of the "safe" line, so pretty low.  This doesnt make much sense though because I added exactly 5 quarts of oil when I did the change. There might be a little over 5 quarts in there since there might be a little leftover 5w30 oil, so if anything there is a small bit more than 5 or exactly 5 quarts, so I'm not sure why it would say that the oil is low.  I have never replaced my dipstick so I doubt that it is the wrong one, but I suppose it could be wrong if it got accidentally swapped with a different dipstick at some point, or maybe it got bent and is throwing the measurement off.

I tried smelling the oil at the end of the dipstick to check if I can smell any gasoline, and I did get a small hint of gasoline odor when I smelled the dipstick.  

Should I let some more oil out even though it has 5 quarts, Or is it possible that its just burning off the excess 5w30 oil from the last oil change? Or could it be that there is too much transmission fluid in there after I added the trans-stop-slip? 

again, this car never smoked before I changed the oil to 5w30 and added the trans-stop-slip. I replaced the oil back to 20w50 and its still smoking, so that leads me to believe that it has something to do with adding the stop-slip.  This still doesnt explain the low oil level reading on the dipstick though- or the slight gasoline smell on the dipstick.  

Sorry for the long post, I just want to be thorough. Thanks again guys!

 

Don C

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Do not drain any of the oil, the level is not too high, now.

My guess is that the vacuum modulator on the transmission is leaking, and sucking transmission fluid into the engine. The vacuum line for it runs up the back of the engine and connects to a fitting on the top rear of the intake manifold. You can pull the rubber hose off the fitting and check the inside of it for oil.

It's also possible the thin oil coated the inside of the exhaust pipes and when they warm up enough the oil starts to burn off.

 
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It was also mentioned in past that the fuel pump diaphragm might be leaking. This will pump gas into the oil for sure had it happen last year. You can test without pulling the pump off just use a vacuum bleeder hand pump like you use for bleeding brakes. Put pump on the hook up for the hose from fuel line and hold finger over the fitting going to the carburetor. If if will not hold a vacuum the diaphragm has a hole in it and needs replacing. Actually take the pump with you if you need a new one and test the new pump at the store. I have had them bad right out of the box.

 

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From some replies, I'm confused, it smokes at the exhaust tips too, or just from the engine/bay?

@david,

Would there not be a strong fuel smel when he checks the dipstick?

 

mcampbell26915

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Hey everyone! quick status report-

I checked the transmission fluid level while the car was idling and it is overfilled a bit.  I took a photo of the dipstick, and to see it just click this - http://tinypic.com/r/63rfok/9

It is kind of hard to see and the picture is a bit misleading so I added a red line to mark where the top of the fluid level is, and I added a blue line to show where the recommended fluid level should be.

I also noticed some transmission fluid around and underneath the carbon storage canister, not sure how transmission fluid would get there but here are two pictures of that as well-  http://tinypic.com/r/20i73pl/9   -  and  -   http://tinypic.com/r/1079hfl/9   -  that blue thing at the top of the photo is the canister, and all that wetspot is transmission fluid.   It should be known that I did spill some transmission stop slip on top of the canister when adding it, and then I tried rinsing it off (which didn't work too well since its so viscous and oily). so its possible that the spilled fluid never got fully rinsed off and instead just spread further and found its way underneath the canister, which could be what we are seeing in that picture.  I just thought I would include that though because that could be some sort of clue if it turns out that its not just spilled fluid.

Don C, I couldnt find the vacuum line that you were referencing.  I took a picture of the top-rear of my intake manifold and that can be seen here- http://tinypic.com/r/200bc5w/9

I circled the only thing coming out of the top rear of the manifold, but I don't think that line is it, but there are two other nozzles on that thing that are capped off (they have been capped off since I bought the car in 2013).  

The green arrow is pointing to the only other line that is near the rear of the intake manifold, but it isn't attached to the manifold itself so I don't think that is the one you were referencing either.  So if you could help me a little more to find that vacuum line then I will definitely check it ASAP.  

200bc5w.jpg


Carolina_mountain_mustangs , would a leak in the fuel pump diaphragm cause all this smoke to come out of the exhaust and engine bay? The smoking didnt start until after I changed the oil and added the transmission fluid stop slip, so I would be really surprised if the fuel pump diaphragm happened to go bad the moment I changed those other things, since I didn't even touch any part of the fuel system.   Hopefully the fuel pump diaphragm isn't leaking, I replaced the fuel pump not too long ago, probably 3 years ago and put less than 1000 miles on the car since.  I also don't smell that strong of a fuel odor from the dipstick, if any at all.

Fabrice , The smoke is coming from the exhaust as well as the engine bay.  Its also coming out of the exhaust leaks near the muffler too, as you can see by the smoke coming out of the wheel wells in this picture- http://tinypic.com/r/2ynfo8y/9

What do you guys think? Thanks again!

Matt

 

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The hose the green arrow is pointing to may be it. Can you tell where the metal tube it is connected to runs to? If it is the one it will run down the back of the bell housing and towards the back of the transmission.

To answer the question about the fuel pump, it could draw in oil, as the pump lever moves in one direction it puts pressure against the diaphragm and forces gas to the carburetor (and crankcase when there is a hole in the diaphragm). When it moves in the other direction it pulls fuel into the fuel pump from the fuel tank and could pull some oil in from the crankcase. As much oil as your car is burning, if this were the case I would think the gas in the carburetor fuel bowl would be noticeably oily.

Did you do anything else when you changed the oil, like replace the PCV valve or tighten the intake manifold bolts?

 

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I was going to suggest that maybe there was too much oil in the crankcase, but I didn't want to make any assumptions or insult anybody.

I had a friend decide to change his own oil, not knowing anything about his car, he opened up the drain plug he found under the truck and emptied it... then added 5 quarts of oil to the OIL fill in the valve cover.

He'd actually drained his manual transmission, and added another 5 quarts to his crankcase - smoked like a chimney when he fired it up.  Once we dumped all the oil, then refilled both crankcase and transmission, everything was fine.

I'd recommend checking your fluid levels in both the transmission AND the crankcase just to make sure that's not the issue.
Eric, Did you just make that up? lollerzChuck
Wow - Sorry I missed this when you replied, Chuck.  

Actually, I did not make that one up.  The guy with the truck was the husband of one of my Airmen back in '95 - they had a '90-something Nissan 2WD pick-up.  He didn't know squat about cars, just remembered seeing someone under the car and removing a plug when changing the oil.  He wanted to do it himself, but didn't think to get someone to help him for the first time he'd ever done it.  We got it to the Auto Hobby Shop (wasn't more than a mile or so away from the base) and put it on a lift, and he pointed out which drain plug he'd removed, and I immediately knew what happened at that point (I was still learning things myself and had never seen anything like that, either - but it made sense after I saw it).  Don, the manager, confirmed my suspicions, so we just dumped the 10 qts of engine oil, picked up some new oil and some 80/90 weight for the transmission, and everything was all good after that.

A few years later while at the Auto Hobby Shop when both Don and Jim were working there, we'd seen that again.  But the kid was one of those that already knew everything about everything, so we just kind of sat back and watched it all unfold, explained what had happened when he came over with his tail between his legs, helped the kid get it back to good, and had a good laugh.  I sure miss those days... and my pals.

 
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