Took my 68 442 out for the first time this year and noticed white smoke from the pass side tail pipe. Im sure its coolent cause white smoke usually is but is there anyway to check if its a head gasket or intake gaskets? Its a 400 engine with 80000 original miles,is this common for this year 400? Any info will help. Thanks! Steve

 

Something to consider- some modern gasoline formulations will emit white smoke on startup or if you get into it hard. Saw a newer Nissan do it just yesterday. Of course the fool was passing me on a double solid yellow going into a couple of blind dips, and he realised he was meeting another car so he had to do something. I was already traveling 5 over on a 2-lane, so didn't really see his need to pass, but...

Monitor coolant usage (remembering NOT to fill the radiator completely; about 3" below the neck is normal cold level on these cars) and if it's apparent you're losing some and not on the ground, run a compression check. If the numbers look good, that's when I'd look into the intake gasket. After 42 years it's possibly eaten up around the crossover passages and allowing some coolant to be sucked in past the intake ports.

 

check to see if it's putting pressure in rad,yes=head gasket

 

All the above posts are true but before you go through any panic, do me a favor.
The steel vacuum line that is running from the rear of the intake manifold to the transmission modulator. Pull it off at either end and see if any drops of transmission fluid come out of it.
I like to do it closer to the modulator on the trans cause it will drip right away.
If you have a drip of fluid it will suck it into the intake at that port and burn it and cause a puffy white smoke as well.
If that is the case a simple modulator change cures it and " away we go".
Let us know your findings.
Good Luck!
Rich

" Some days your the whitewall others the curb"

 

That's a good one that I had not thought of Rich.

 

Thanks for the info guys! Ill just order the trany modulater cause its like $12 bucks I just want to be sure its not a head gasket and I will check into it more. I have a new carb and intake that I was going to put on the car but Im going to wait and make sure I dont have a blown head gasket. If the intake gaskets are bad then the new carb,intake and gaskets should take care of it. Thanks again for all the info I really apreciate it! Steve

 

Steve,
I you replace it let us know if it worked or not or if the old one was a leaker.
Also if your shift points change a bit they can be adjusted through the outlet where the vacuum line connects with an allen wrench!
Good Luck!
Rich

 

Ok guys heres the deal, I checked the hoses on the trany modulator and there is no sign of trany fluid. I did a coolent test that checks the coolent for hydrocarbons and any other signs of exhaust and the test was succesful. Im pretty sure the intake gaskets are at fault here wich is ok because I was going to swap out the original carb and intake with a performer intake and edelbrock carb. Thanks again for the feedback I really apreciate it!