76 K5...white smoke on start up!?

[HK_G3]

I have a 76 K5 Cheyenne, original motor with 47,000 on it.

A couple months ago my mechanic told me I had a leaky head gasket..he told me it wasn't substantial enough so I could put off the repair since this truck is only driven about 30-40 miles per week..usually less.

Anyway, when I turn it over *sometimes* I end up getting white smoke out the exhaust for about 5 seconds..sometimes it's a little and sometimes it's a VERY noticeable "cloud"..

Anyway, it stops and never happens when the truck is in gear or in park...just during initial start up.

Now I noticed something strange...today I fired it up and no smoke...drive for a few miles and get home, kill the motor and about 3 hours later I had to run out. This time it smoked, not as much as normal but enough to be noticeable. It smells like exhaust I really can't tell if it's sweet or not.

Since I'm still driving it like this I gotta ask:

- am I causing more damage to the motor by continuing to drive it? right now it's my only ride for the summer since I sold another car recently.


- Should I get the gasket replaced or just the scrap the whole engine? I'm tight on money and the original motor has low miles...would like to save it if possible...


- This is the one I fear...scrap the whole truck! I have $7K or so into this, little to no rust and good body w/ good original paint...new tires and rims on it and interior is clean. Too nice to turn into beer cans IMO!

I'm in NJ and guys around here want $2,000-$3,000 in labor to replace the gasket (or gaskets) and a rebuilt motor will likely set me back $3K or so plus labor which could being me to $5K-$6K in these parts...I have no real mechanical experience taking apart engines.

Opinions on smoke and what to do with this truck appreciated.

 

[BloodMoon]

White smoke equals coolant burning in the engine, or moisture in the exhaust pipes turning to steam. check radiator and overflow reservoir for coolant level.
The leak sounds small as it isn't constant smoke, sounds like while the engine cools and external and internal temperatures change that a small amount of coolant is working its way passed a head gasket, if the cylinder was cracked it would be a pretty constant stream of smoke.

Make sure you check the oil, if it a milky chocolate kind of color then coolant has worked it way through a crack and the oil is contaminated, if so, do not run the engine as it will most likely lead to major damage.

We'll see what other people have to say, but if it's not as bad as you say it isn't, then I'd leave it alone, do plan on addressing it when funds permits

Check around on prices, also look at having seperate people do the work, for example my engine builder only wants about $1600 (think labor, not sure what parts are included) to rebuild a 350. And my mechanic is charging between $700 to $1200 to remove and install an engine.

. And you did mean to 47k miles right? Not 147k?

At 47, it should still have life left, if the truck sat long then gaskets would dry out and leak. At 147k you could rebuild the top end, but with a fresh top it would eventually lead to blowing rings on the bottom end. So you would have to get into it twice.

 

[HK_G3]

White smoke equals coolant burning in the engine, or moisture in the exhaust pipes turning to steam. check radiator and overflow reservoir for coolant level.
The leak sounds small as it isn't constant smoke, sounds like while the engine cools and external and internal temperatures change that a small amount of coolant is working its way passed a head gasket, if the cylinder was cracked it would be a pretty constant stream of smoke.

Make sure you check the oil, if it a milky chocolate kind of color then coolant has worked it way through a crack and the oil is contaminated, if so, do not run the engine as it will most likely lead to major damage.

We'll see what other people have to say, but if it's not as bad as you say it isn't, then I'd leave it alone, do plan on addressing it when funds permits

Check around on prices, also look at having seperate people do the work, for example my engine builder only wants about $1600 (think labor, not sure what parts are included) to rebuild a 350. And my mechanic is charging between $700 to $1200 to remove and install an engine.

. And you did mean to 47k miles right? Not 147k?

At 47, it should still have life left, if the truck sat long then gaskets would dry out and leak. At 147k you could rebuild the top end, but with a fresh top it would eventually lead to blowing rings on the bottom end. So you would have to get into it twice.

Thanks for the reply,

Yes, I meant 47K not 147K..

I cannot speak of the previous owner but I'm certain this sat for some time in NC without being driven before I got it so from sitting that would make sense (gaskets drying out and leaking).

I'll check the oil before I run it again and report back.

Coolant level has been good, I flushed it last year (exactly 1 year) and last week it took under 3 ounces of 50/50 mix so coolant level hasn't dropped substantially. Temp is fine, month ago drove it up near NYC and back a good 200+ mile trip and the temperature stayed stable.

I'll keep driving it with my fingers crossed, if I can get 6 or so months out of it without the problem getting any worse I can likely cough up some cash to get the repairs underway or sell of something else to fund the repairs.

 

[HK_G3]

Another problem I'm facing is the truck is due for inspection in 45 days, any visible smoke and boom you fail...

Someone had suggested blue devil, I know many guys will consider this snake oil/outright crap but I'm curious if it would help seal (or cover up) this small leak..maybe worth trying or complete waste of money?? I've heard it can cause more issues so I'm iffy about trying this.

 

[diesel4me]

I'd NOT use "Blue Devil",I have seen it plug up several engines that used car dealers tried it on ,it hardens like portland cement in the coolant passages..

If I were going to use any type of sealer I'd trust Aluma-Seal or Copper-Seal powder most..it will work if sealer will help,and wont plug anything up like the heater core..

I've seen many Chevy's with heads that weep coolant after sitting due to small cracks..often sealer will stop it enough to avoid having to fix it "right"..

It might be OIL you see burning ,it could be leaky valve stem seals or guides allowing oil to sneak into the combustion chamber after it sits awhile,then burns off next time it is started..

On the other hand its very possible it still has the original stamped steel shim head gaskets ,that have now corroded enough to let coolant sneak in the combustion chamber--or small cracks between the valves in the head that do the same,after it sits long enough..
If you hear the engine "bind" when you first go to start it,then it turns over normally,it is more likely coolant than oil in the cylinder..one way to confirm this is to start it cold,if it smokes,shut it right off,then remove all the spark plugs..you'll find one with drops of green coolant or looks "steam cleaned" compared to the others,in the cylinder thats got the problem..

 

[paratrooper307]

I'd NOT use "Blue Devil",I have seen it plug up several engines that used car dealers tried it on ,it hardens like portland cement in the coolant passages..

If I were going to use any type of sealer I'd trust Aluma-Seal or Copper-Seal powder most..it will work if sealer will help,and wont plug anything up like the heater core..

I've seen many Chevy's with heads that weep coolant after sitting due to small cracks..often sealer will stop it enough to avoid having to fix it "right"..

It might be OIL you see burning ,it could be leaky valve stem seals or guides allowing oil to sneak into the combustion chamber after it sits awhile,then burns off next time it is started..

On the other hand its very possible it still has the original stamped steel shim head gaskets ,that have now corroded enough to let coolant sneak in the combustion chamber--or small cracks between the valves in the head that do the same,after it sits long enough..
If you hear the engine "bind" when you first go to start it,then it turns over normally,it is more likely coolant than oil in the cylinder..one way to confirm this is to start it cold,if it smokes,shut it right off,then remove all the spark plugs..you'll find one with drops of green coolant or looks "steam cleaned" compared to the others,in the cylinder thats got the problem..

I know you said you weren't real familiar with engines, but a set of the Fel-Pro blue gaskets are very inexpensive, and these engines are about as easy as it gets when it comes to removing the heads. If you don't mind getting your hands dirty for a day, you can fix it right assuming the gasket is the problem. 2-3k is ridiculous for a gasket job on these motors, considering a brand new 350 is only 1500 from Jegs, and a rebuild usually goes for less than that.