White smoke at idle, out of ideas!!!!

T

TucsonHooligan

Well-known member
I recently rebuilt a '67 200. I have about 1k miles on it and now it billows white smoke out of the exhaust at every stoplight. White smoke=coolant, right? So I checked all the plugs to see if they were light colored or wet. No luck. After scrambling to find out what it was, I eventually pulled the head to have a look. All pistons look the same, as well as all combustion chambers and valves. No obvious signs of a coolant leak or cracks anywhere in the head or block. I regasketed the head and assembled everything back together and it still smokes like crazy. The engine runs like a top, idles smooth and cruises without a glitch. What the heck is goin on here?!?! I'm stumped and all outta ideas.
 
Doesn't seem to be a lot of coolant loss, and I thought what I had lost could have been due to to hoses that weren't torqued enough and were weeping a bit. Tightened em down, so now it remains to be seen what I lose. Also, just grasping at straws here, I am running the water choke on the HW 5200. I looked at it and it doesn't look like there's any way it could get into the intake, but I could be wrong. Any chance of that? I'm off to work now so won't be able to reply for 9 hours or so, but please, any help is appreciated.
 
if you have a carb heater plate I recomend by-passing that. when you torque the head do you go from middle to outside in 3-4 torque cycles? (45-55-65-75) the order is important getting all 'bubble's' out. also, after 2-4 heat cycles remember to re-torque the head and exhaust.

just becasue it's white doesn't mean it's not oil too, you confirmed it's water, but keep an eye on oil also especialy if it mixes.

keep posting your finds we'll knock it out in due time.
 
I am running the water choke on the HW 5200. I looked at it and it doesn't look like there's any way it could get into the intake, but I could be wrong. Any chance of that?
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It gets hooked up in the the heater return line.

If you did not see anything (signs of coolant) in the head comb. chamber or in block cylinder's, then it could be internal IE exhaust port in head though not good at least with it outside the C.C. will not have much of an effect how it runs. Have had good luck using KW block sealer on internal leaks and head gaskets that were leaking slightly so that's what I would do. Other than that you would need to find another head, Good Luck
 
Normally if its coolant leaking into a cylinder the piston crown would be clean of carbon.
A cracked head leaking coolant into an exhaust port.
The X factor here is you see no loss of coolant??
Loosen the radiator cap to relieve presssure in the cooling system & see if you notice a change in the smoke.
Can you smell a pungent exhaust odor which is a clue of coolant leakage.
Are you sure its not white smoke just from cool ambient outside temperature which will produce white smoke, but just has a typical exhaust smell. Good luck Bill
 
If you have an automatic transmission , check the vacuum modulator for leakage into the vacuum line . Transmission fluid can cause a light colored smoke if it gets into the intake .
 
I managed to find a comp at work with internet. Lucky me.

Anyway, I'm terrible at using the quote function, so I'll try to answer each post chronologically:

No carb heater plate in use. Head torqued in order shown in handbook, from inside to out, in 10 ft lb increments from 35 to 75. Oil level seems to be fine, but the pistons and head did seem to have an awful lot of carbon on them for only 1k miles...

I'm reluctant to use block sealer immediately to cure it until I have exhausted all options. I wouldn't think I would need to do that on a new motor, but its looking like I may have to no matter what. Damn shame that is...

All pistons have and combustion chambers had equal amounts of carbon build up and no one cylinder looked like the culprit, i.e., not clean. I'll try the radiator cap trick when I get home tonight. The smell from the exhaust is kind of sweet but it does burn the nose. It's definitely not steam or the result of temp, it's full-on smoke. Filled the garage after 5 minutes of idling...

I have an auto tranny, but I disconnected all the vacuum lines and plugged the ports (the PCV manifold port as well) and ran it to isolate the carb from any potential oil intake. No dice, same amount of smoke.

I'm at my wits end here, it's driving me crazy. I built this motor up over a 2 year period and finally got the car back on the road and now this. I fill the intersection with smoke every time I stop. People roll up their windows when they get stuck next to me. Last resort will be the alumiseal, but I would hope I could sort it out before I have to do that. I hate to have to think I'm running a motor that is depending on a quick fix from Autozone to survive, and that any moment the potential crack could widen. Thanks for all the help guys, and keep it comin!
 
I seal the gasket to the block/head every time just as a precaution, just don't want to tear it apart gain.

after sitting for 2 years, how did you break in the motor? did you dump oil everywhere? prime the oil pump system?
where was the car stored during the 2 years? when was the exhaust system installed prior to starting?

I honestly don't think any of my questions will help pin point but it's what I would think about.
 
Does the engine consume oil????
Just wondering if the oil rings are not siezed in the ring grooves in the piston due to the engine sitting.
Run a compression test & let us know the details???
Another option is put a pressure checker on the cooling system & pump up the pressure to 25#.
Is the smoke worse??
Another option is take the vehicle out for a test drive & drive it like you stole it.
Run the crap out of it & see what happens. Bill
 
Broke in the motor by doing the cam break in then trouncing the crap out of it on the freeway in 10 second intervals, then letting off the gas. Didn't drop any oil at all. Primed the system with a drill and socket using the hex driver that goes into the pump. Watched it till oil came out of all the rockers. Exhaust was put on the day before I started it for the first time...

From what I can tell it doesn't consume oil. The smoke isn't blue and it smells too sweet to be oil. I ran a compression check on all cylinders and got between 115 and 125 on all of them. Put a pressure checker on the radiator and pumped it up and the gauge slowly moved down after 5 minutes, but i didn't run the engine with it on there, just did it while it was off. I have put some rough miles on it trying to make sure the rings set properly, but I assume since the compression test was good, that it isn't rings...

Hope this helps. Thanks again, there are no bad suggestions, I'm willing to try anything right now.
 
Just on a flyer since it seems most of the bases have been covered, any chance something was placed or crawled into your exhaust while the engine was out? Paper, rag, mouse, etc... maybe slowly burning off, which would cause white smoke.
 
Only other thing I know of to do this is a power brake booster. But I'm sure if you had that, you would have noticed lack of brake fluid by now. Never seen one leaking coolant into cylinders that wasn't evident. Subscribing, I'm curious.
 
TucsonHooligan":1bg5qtsr said:
...'67 200. ...billows white smoke out of the exhaust at every stoplight. ...pulled the head...runs like a top, ... What the heck is goin on here?!?! I'm stumped and all outta ideas.
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conjecture backed up by opinion:

What does the white smoke smell like? , I'm serious, if billowing as imagined. ..smoke getting worse and worse at idle often is blowby related -
simple hidden problem like PCV system out of whack, serious like broken ring suspect in new builds... 'had white smoke (antifrz smell :unsure: ) startup and disappear when warmed - cracked head sealed up when warm .


took a few tries ... ,

Have Fun

 
In order again...

Don't think there's any dead rodents up the pipe. I've smelled a burning raccoon (don't ask) and this is nothing like it.

No power brakes on this one so no booster.

Smoke smells kind of sweet yet burns the nose a little. I would think if the rings were bad it would smoke on start-up too, but this take about 5 minutes to appear real heavy.

I didn't rebuild the head, I had a shop do it. I would hope they put valve guide seals in!

Could be burning oil I suppose. I will check all fluid levels tomorrow and see if any have dropped after about 100 miles of driving.

Thanks guys!
 
You could pressure test the long block by blocking off all Radiator and Heater hoses and make or pickup a back flush kit for the fittings to hook it up to a garden hose. Pull the rockers off and spark plugs out, turn on the water and watch it if you get water out the exhaust, a plug or in the oil. From your description I am still thinking a exhaust port in head.
 
I pressure tested the cooling system and it didn't hold. The gauge didn't move visibly, but after I left it for 5 minutes it was obvious. It looks like my coolant level had dropped, but I'm not sure if its from burning off or from air pockets being cleared after I replaced the head gasket and topped off the system. I'll drive it a bit more to know for sure.

Jackfish, I would be inclined to agree, but its a brand new motor so no carbon built up yet really. Plus it happens consistently at idle, no change in amount or frequency.

Gonna try the radiator cap off trick right now, will let you guys know the results if I can get to a computer again before I have to leave for work.
 
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