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Discussion Starter #1 (Edited)
I have anti-freeze coming from my exhaust again. It collects at my collectors and mufflers. It does not show up when running, and no big plumes of white smoke. I only notice it after I pull out of the garage, so guessing it is after it sits for a while. No anti-freeze in the oil either. It is a big block with no heater core hooked up if that really makes any difference.

I did a cooling system check twice at 15psi and it held twice, at least until the tested blew out of the radiator. I did a compression check and got pretty much 160psi on all eight cylinders. So how the heck could it be a head gasket or cracked head?

I know I probably will not be able to tell if a head gasket after pulling the head off due to the damage of separating the head from the block. I am guessing the next step I need is to pull the heads and need to have them pressure checked?

I was told to pressurize the cooling system with all the spark plugs removed and crank the motor to see where the coolant is coming from. Does that sound like a better step?

I am not a good mechanic, I know I am not much more than a parts changer and need help with diagnosing. Has anyone had a similar problem?

I need help guys, please help if you can. :eek:
 

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6 cyl but similar problem

My 250 was blowing white smoke at startup after being parked for a couple of days. Turned out to be water weeping from a head bolt on back drivers side corner. Water would come out of the bolt as the engine cooled and go right down into the exhaust manifold. Did all of the same tests you mentioned, but could not figure out what was causing it until my exhaust manifold finally cracked. Can't remember if big blocks have head bolts outside of the valve cover or not though...just something else to look for. Good Luck!
 

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You sure its coolant and not just condensation. If it's coolant, I would pressurize the cylinder with compressed air and see if the coolant in the radiator is bubbling up. It's probably a head gasket, but it's sounds like the leak is really small. If there is a crack it might be to small to see with the naked eye, you might have to get the heads magnafluxed at a machine shop. How much coolant is there on the floor when you move the car?
 

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Discussion Starter #5
It unfortunatly is anti-freeze. There are puddle about the size of softballs at the joints where it can leak. I sure hope it is not a crack in a cylinder wall, if so I am going with a stock small block until I get all the parts for an LSX swap (in other words, a few years).

69novashotgun, did you get anti-freeze in your oil? Were you able to spot the crack without magnafluxing the block?
 

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I assume it's only one collector/one side of the engine.

Before you start it one day, use some clean paper towels and wipe down the outside of the headers to make sure it's not running down the headers from some place else. Check on top the collectors. If your engine is dirty, clean it good then look for the leak again. Fluids can run a long way horizontally.

Normally a cooling system pressure test will detect a blown head gasket, cracked block or cracked head.

If it still appears to be coming from the inside of the headers, unbolt the headers from he head and see which exhaust port is moist with the anti-freeze. Maybe leave the header off for a few hours with a white paper towel in each exhaust port. Pull the spark plugs on that side and inspect them.


I had a cracked block in a cylinder wall in my '69 Nova. No anti-freeze in the oil and no oil in the anti-freeze. Car ran fine, it would overheat going over MPH. Compression test looked good, cooling system pressure test failed.
 

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Discussion Starter #7 (Edited)
My 250 was blowing white smoke at startup after being parked for a couple of days. Turned out to be water weeping from a head bolt on back drivers side corner. Water would come out of the bolt as the engine cooled and go right down into the exhaust manifold. Did all of the same tests you mentioned, but could not figure out what was causing it until my exhaust manifold finally cracked. Can't remember if big blocks have head bolts outside of the valve cover or not though...just something else to look for. Good Luck!
Good suggestion. I don't know if and which bbc head bolts require a type of thread sealant. Anyone know the answer?

I might see if I can find an adapter that will allow me to compress the cylinders with air and see what happens.

Paul, could to spot the crack in the cylinder wall by eye? Oh, I got an H-pipe, so it collects in both sides. I tried last fall when this happened to unhook the headers to try and see, and of course it would not leak.......

thanks for the help/suggestions so far.
 

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Paul, could to spot the crack in the cylinder wall by eye? Oh, I got an H-pipe, so it collects in both sides. I tried last fall when this happened to unhook the headers to try and see, and of course it would not leak.......
Yep, but it just looked like a 2 inch long vertical scratch. You could catch your fingernail on it, it was only a few thousands high. Had cracked heads that you could not see till they where cleaned and magnafluxed.
 

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The end result in any situation is not good.
Just as well pull the engine for the repair.

head gasket or head, it's still major!

Al
 

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My small block had anti freeze leaking from a header bolt before, had to use sealant on the thread. Dunno if big block heads are the same though.
 

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Good suggestion. I don't know if and which bbc head bolts require a type of thread sealant. Anyone know the answer?

I might see if I can find an adapter that will allow me to compress the cylinders with air and see what happens.

Paul, could to spot the crack in the cylinder wall by eye? Oh, I got an H-pipe, so it collects in both sides. I tried last fall when this happened to unhook the headers to try and see, and of course it would not leak.......

thanks for the help/suggestions so far.
Try spraying some brake clean or carb cleaner! The crack will be the last thing to dry out!
 

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Discussion Starter #13
This may all have been caused by laziness....... :(

Ever since I had the car, it would take a while to warm up, but when it did, it got warm when moving slowly, more so than any other car I had.

I had always wondered if there even was a thermostat in the motor. Too lazy to take a look and replace the housing gasket.

Well, upon the beginning of tear down, look what I found under the thermostat housing? A restrictor plate.....

Doesn't pay to be lazy, but yet I do it again and again :rolleyes:
 

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Discussion Starter #14
Well, drivers side head is off. What a PITA it is to remove them while still in the car :beat:

Headgasket stuck to the head and it looked perfect. Looked a bit in the cylinders and they looked fine with only lines was the cross-hatch pattern. I still need to rotate the motor to see all of the cylinders though.

Pistons had very little carbon build up and much of the outside of the pistons were clean, only real carbon was on the domes. I don't know, but it looks like this motor was pretty fresh?

If the pistons are oversized, don't they usually have that stamped on the tops?
 

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get some good pics of both sides of the head gasket and the block and head.

Al
 

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Cracked Head or Head Gasket?

Hey Now, Sounds like it could be either one, including cracked cylinder wall as was suggested. The Head bolts do need sealant on them and be sure to check that the Deck is straight also, along with the heads. [The surfaces that your headgasket goes between to seal] Another possible leak area is on BBC's you need to have a machine shop add two head bolts per side on your engine. These are accessed through the head intake ports and the bolts are recessed into the runner port so it doesn't disrupt the intake air fuel ratio and flow. Yes if your engine has been bored out, the tops of the pistons will have .030 or .040, .060 stamped into the top of the piston. Respectfully "Bill's" II
 

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if you were ingesting water into a cylinder for a good length of time that piston should be cleaner than the others generally. ( Am a mechanic and have pulled off a many head and was like ?????). Next time before you pull the heads I see you are in MN and probably do not have smog but if you can find a shop with a gas analyzer put the sniffer in a clear bottle then put the bottle in the radiator mouth while rapping the throttle if you see more than 50 HC ppm good indication that there is exhaust gas getting into the coolant from either a gasket or crack. When examaning the gaskets look for darkness from the compression ring to a water passage or even a cracked compression ring (if your gaskets have one)
 

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Discussion Starter #18
Update:
Pulled the other head. Same thing with passengers side head. Headgasket stayed in one piece and looked in good shape. No anti-freeze in this bank of cylinders. Had it in all four of the drivers side, but think it came from the coolant passages as the block did not drain down.

All four cylinders had even carbon build-up. Has .030 over pistons, cleaned one to find out. I had a good look at two of the cylinders and they looked good. One had something I wasn't sure about, but kept trying to drag my fingernail across it and could not feel anything.

I will crank over the motor by hand tomorrow to check the other five cylinders.

So far I am guessing either:
a cracked or warped head
cracked block that I have not seen yet
one of the bolts had allowed anti-freeze up into the exhaust, not the cylinder.

If anti-freeze is burning in the combustion process, would there be big plumes of white smoke, or could it just put out small whisps of smoke?

I looked and never had seen any smoke coming out after both times it left puddles, but do know it was somehow internal as the four puddles were where the mufflers were, and where the collector bolted to the exhaust system.

If I do not see any cracks, and the heads come back fine, would I be stupid to put it back together? I really rather not tear it down to the bare block if possible.

Also, when they usually check heads for cracks, do they need to strip them? Or can they check them when assembled?

Sorry for all the questions, but I am more of a parts changer than a mechanic, and know to seek out advice from others who are wiser.

will post up picks in the next couple of days. What areas do I need to take pics to help? All eight cylinders? Head gaskets?

thanks again for those who can help me. :yes:
 

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Bill,

take the heads, head gaskets and spark plugs in the same holes they were in to a machine shop and let them look for your problem. Don't scrape or mess with anything. Ive never seem a cyl wall split unless it's big time power. Even major detonation will take the piston out first.

Jim
 

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its possible you could have crack in the valve seat area. Only way antifreeze is gonna get into the exhaust is thru the port. If you had anti-freeze in the chamber it would burn out and you'd get the white smoke out the exhaust. I had a crack in my intake port on my 406 that you couldn't see with the valves installed. I ran the engine and thru one heat cycle, the next day I tried to start and it wouldn't start. Tried to turn the engine over, could not. Found #3 cylinder had filled up with water. Pulled the plug and water gushed out. I truely got luck it didn't hydralock the engine.
 
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