Slant Six Forum :: head gasket?

I was getting some coolant leak at the manifolds. It was when first started cold, a decent amount of coolant, say 10-20 ml on the side of the block below the manifolds. I could see steam rising from and bubbles at the manifold gasket between #4 and #5. I removed the valve tin and torqued the head bolts, some were looser than others. I torqued to 80 lb-ft.

I don't see the leak at the manifolds any longer, but my exhaust is pretty moist. I let it warm up for at least 10 minutes, but the exhaust is still pretty wet, when I revved it up there was water at the exhaust.

I checked the coolant in the radiator (I'm using waterless), there are some bubbles when the thermostat first opens but none after that, no steady bubbling or anything.

The temperature is running normal, and holding steady.

Do I have a head gasket leak? It's just been rebuilt, but it seems like a leak to me. I would expect the exhaust to be dry after 10 minutes of running.

Brian

Author:	'67 Dart 270 [ Sat May 16, 2015 4:51 pm ]
Post subject:	head gasket?
I was getting some coolant leak at the manifolds. It was when first started cold, a decent amount of coolant, say 10-20 ml on the side of the block below the manifolds. I could see steam rising from and bubbles at the manifold gasket between #4 and #5. I removed the valve tin and torqued the head bolts, some were looser than others. I torqued to 80 lb-ft. I don't see the leak at the manifolds any longer, but my exhaust is pretty moist. I let it warm up for at least 10 minutes, but the exhaust is still pretty wet, when I revved it up there was water at the exhaust. I checked the coolant in the radiator (I'm using waterless), there are some bubbles when the thermostat first opens but none after that, no steady bubbling or anything. The temperature is running normal, and holding steady. Do I have a head gasket leak? It's just been rebuilt, but it seems like a leak to me. I would expect the exhaust to be dry after 10 minutes of running. Brian

Author:	WagonsRcool [ Sat May 16, 2015 5:22 pm ]
Post subject:
First thought is that your manifold attachment studs might not be sealed properly. Those stud holes go into the cooling jacket & if you don't have some sealer on the stud threads then you'll have seeps.

Author:	Reed [ Sat May 16, 2015 5:40 pm ]
Post subject:	Re: head gasket?
Quote: I was getting some coolant leak at the manifolds. It was when first started cold, a decent amount of coolant, say 10-20 ml on the side of the block below the manifolds. I could see steam rising from and bubbles at the manifold gasket between #4 and #5. I removed the valve tin and torqued the head bolts, some were looser than others. I torqued to 80 lb-ft. I don't see the leak at the manifolds any longer, but my exhaust is pretty moist. I let it warm up for at least 10 minutes, but the exhaust is still pretty wet, when I revved it up there was water at the exhaust. I checked the coolant in the radiator (I'm using waterless), there are some bubbles when the thermostat first opens but none after that, no steady bubbling or anything. The temperature is running normal, and holding steady. Do I have a head gasket leak? It's just been rebuilt, but it seems like a leak to me. I would expect the exhaust to be dry after 10 minutes of running. Brian Moisture out the tailpipe is (a) condensation coming out as the exhaust line heats up and (b) a natural byproduct of burning hydrocarbons (HC + O = H2O). A head gasket leak into the cylinder would manifest as white sweet smelling smoke coming out of the exhaust pipe all the time. If you don't run your car very often or only for short trips, then a large amount of condensate can build up in area like your muffler. I have actually had a muffler rust out from the inside out on a vehicle I didn't drive very often that had the muffler at the low point in the exhaust and far away from the engine.

Author:	'67 Dart 270 [ Sat May 16, 2015 7:44 pm ]
Post subject:	Fair enough...
I don't think the coolant was from the studs, they were sealed well. Also, I've done a number of rebuilds over the years, a new engine tends to run hot and dry at the tail pipe, no (observable) water after it's warmed up. I fully understand that combustion of hydrocarbons gives CO2 and H2O, but this seems excessive. That all said, this is a new rebuild, new head gasket, both block and deck have been milled, it is hard to imagine a head gasket leak. Also the temperature is running normal. BUT, I've seen more than one head gasket leak in my day, this is awfully moist to wet effluent; I would expect a dry hot exhaust from a fresh motor - and there is no doubt there was (significant) coolant coming from the manifold area before I retorqued the head bolts. If it was from the studs, retorqueing in the head bolts would have made no difference. brian

Author:	'67 Dart 270 [ Sat May 16, 2015 7:59 pm ]
Post subject:	Reed
The exhaust is "white" with steam for the first 5 minutes, after that it clears a good bit, but still there is significant moisture at the tail pipe. When I rev the motor to a couple thousand rpms, there is water dripping from the tail pipe. I've experienced engines with head gasket leaks before and those without, this seems like a lot of moisture. I would expect a dry/hot exhaust with a fresh rebuild. Otherwise, the engine is running perfectly, temperature is normal, timing is set, starts easily/no issues. I wouldn't be concerned except that I had a significant coolant leak under the manifolds before I retorqued the head bolts. Waterless coolant is propylene glycol (80%) and ethylene glycol (20%), so it would combust to make plenty of water. brian

Slant Six Forum https://slantsix.org/forum/

head gasket? https://slantsix.org/forum/viewtopic.php?t=57703	Page 1 of 2

Author:	Reed [ Sat May 16, 2015 8:19 pm ]
Post subject:
Time for a leakdown test then.

Author:	'67 Dart 270 [ Sat May 16, 2015 8:34 pm ]
Post subject:	leakdown test
Reed, Remind me of the leak down test. How does the leak down distinguish from a valve leak, a head gasket leak and piston ring leak? Brian

Author:	makapipi [ Sat May 16, 2015 11:18 pm ]
Post subject:	head gasket coolant leak
you could remove the spark plugs and read them, if very clean, not tan color, there probably is leakage

Author:	slantzilla [ Sun May 17, 2015 12:18 am ]
Post subject:
Are you driving it or just warming it up in the driveway? How big is the exhaust?

Author:	'67 Dart 270 [ Sun May 17, 2015 10:17 am ]
Post subject:	slantzilla...
I was just warming it up in the garage, I did take it around the block as well. I swapped out K frame, so it's not aligned, just roughed in; I can't take it on the highway or anything yet. I don't smell coolant at the exhaust, just lots of moisture at the tail pipe, even after it's fully warmed up. I'm wondering if it might be leaking at a stud and running into the exhaust and/or intake port, perhaps that would give the same symptoms without it being a head gasket leak. I did snug the manifolds before retorquing the head, and the leak seemed to reduce with that some, perhaps I simply diverted a stud leak to the exhaust port? I'll pull the manifolds and check the studs first. brian

Author:	Reed [ Sun May 17, 2015 10:29 am ]
Post subject:	Re: slantzilla...
Quote: I'm wondering if it might be leaking at a stud and running into the exhaust and/or intake port, perhaps that would give the same symptoms without it being a head gasket leak. I did snug the manifolds before retorquing the head, and the leak seemed to reduce with that some, perhaps I simply diverted a stud leak to the exhaust port? I'll pull the manifolds and check the studs first. brian It could be that. The 225 in my brother's 83 Dodge van was leaking at the rearmost intake bolt and some of the coolant got into the exhaust line. A leakdown test is where you pressurize the cooling system and watch/listen for leaks and try and track down where the leak is. You can also pressurize each cylinder and listen for leaks into the coming system and excessive blow-by.

Author:	'67 Dart 270 [ Sun May 17, 2015 10:47 am ]
Post subject:	OK, Reed
Thanks, so it could possibly be coolant getting into the intake port. I have a hard time believing a new rebuild would have a head gasket leak (and of course I loathe the idea of pulling the head, ugh). I'll check the manifold studs and report back. brian

Author:	'67 Dart 270 [ Sun May 17, 2015 10:55 am ]
Post subject:	but...
If I can't find anything, I'll do a leakdown. BTW, the oil is clean, there is no coolant getting in there. brian

Author:	DusterIdiot [ Sun May 17, 2015 11:15 am ]
Post subject:	It can...
Quote: I have a hard time believing a new rebuild would have a head gasket leak The reason I switched to Victor- Reinz over Fel-pro was because I had 2 moderate compression rebuilds lose their head gasket in the first few thousand miles...the deck and heads were machined and I checked the mating surfaces and you couldn't get a .001 feeler tape under the machinist edge over 30"...so it can happen.

Page 1 of 2	All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/

Author:	'67 Dart 270 [ Sun May 17, 2015 1:09 pm ]
Post subject:	I think it's the studs
I pulled the manifolds and there was coolant around two or three of the studs. For some reason the sealant failed, it was cracked and hard already. So, this makes sense, the coolant leaked into the intake port, was going through the combustion chamber and out the exhaust. I was seeing a "splurt" of coolant upon startup, then less during running. http://s785.photobucket.com/user/67dart ... f.jpg.html The thing is, my cooling system has no pressure on it, you can take the radiator cap off when it's hot; I'm using waterless coolant. Seems weird that it could leak that much without pressure on the system. Anyhow, I'll drain it below head level, pull the studs and reseal them, go from there. Anybody want to recommend the best sealant? I believe they had pipe dope on them, it's supposed to stay flexible, but perhaps it was an old batch or something, because it was brittle already. Brian