Re: Tom has a gas leak and it isn't Wanda's cooking

[tsm1@domain.elided (Tom Mandera)]

>I believe it's quite normal for the coolant to expand as it warms and to
>overflow out the top of an open radiator.  This is certainly not the same

That was my assumption.  I assumed the engine warmed up, the thermostat
opened, and since there was ZERO pressure holding ability in the system, the
antifreeze would naturally warm up and expand, causing it to overflow.

I've had the motor running for an hour or more in the driveway and never
experienced an overheat or anything similar.

>> NAPA should have new head gaskets for me by Wednesday or so.. $50 

They're ordering them in, though I haven't paid for 'em yet... 

>I'm not up to speed on your entire thread here . . . 

My 63k mile "good" 304 is smoking... what I believe to be white smoke is
emerging from the exhaust.  It used to do this 2 years ago, but then it was
only a puff at startup... I can deal with that.  Continous smoke is an issue
for me tho'.

It was suggested by a friend that I just do the swap, then worry.  He's had
other friends resurrect old motors that hadn't been run for a while, and the
smoking stops.  I've run the motor for a long period of time... but
generally that's at idle, not racing around town (the Scout is missing a
front hub, a rear driveshaft, and any sort of ability to make a controlled
stop with the brakes). 

I may very well be concerned about nothing, and it could all just go away
with a week or two of driving on it....

OTOH, if there's something like a head gasket that should be changed out,
now would be the time to do it (I'm draining the coolant and oil for the
motor swap anyhow, and the motor will be out of the truck at some point
while I change the rear main seal).

Thus I thought I'd look into what could be the cause of this smoke, and see
if it's something I can/should remedy prior to swapping it.

>Disconnect all attachments of the top-side engine electrical harness
>(ignition, temp, charging, etc.).  Disconnect throttle linkage, vacuum to

See, this isn't so far off from all the little things I need to do to yank
the motor anyhow.... so if yer gonna do it... while you're in there...

>If a defective head gasket is allowing hot combustion gases into the
>coolant, you will surely overheat as well as blow a few bubbles.

No bubbles, no overheating...

>If you think you're sucking coolant *into* the cylinders (causing your
>"smoke"), there will almost certainly be a distinctive ethylene-glycol
>aroma to the exhaust.

Hmm... time to head over to the Chem Lab to freshen up on my
"ethylene-glycol" sniffer test... it certainly doesn't smell so great going
into my lungs... particularly nice since the '72 has driver's side exhaust,
and it's parked just to the left of the open garage door...

>You mention that you've purchased the head gaskets -- but you need 

Order, not bought... *yet*  But it takes 3 days to get all of the "good"
stuff in, so it was a pre-emptive strike.

>an entire "top end" kit.  You'll need valve cover gaskets, plus intake &
>exhaust manifold gaskets at a minimum.  If you have any leakage around your
>valley pan, now's the time to correct it while the intake is off.

*That* was the other question... is it worth all that work for just the head
gaskets, or if I'm going in there, do I just do it ALL?  Or *must* I do it
all?  Once you take it apart, you're due for new gaskets...

I'll do the compression test after work and post the results...

We'll see how the outcome goes... I'd really like to be JUST concerned with
dropping this motor in, instead of any "repairs"...

It's gonna be a fun weekend as it is!

Thanks, Bill.

-Tom