Coolant leaking out of valve cover hole?

dagit · 07-12-2006, 04:00 PM

i just recently started giving my 68 289 some needed attention. it needed a new carb. so while i had it off i took off my intake manifold and repainted it. after reassembling everything its been like 4 months since she last ran. well i got her started today and it sounded rough. there was a little bit of clacking so i decided to take off the valve covers and spray some lube to try to get the valves from sticking. well as im unscrewing the front bolt of the valve cover coolant started to come out of the hole! Im getting freaked out thinking i blew a head gasket or something but theres no coolant in the oil. also it was coming out like it was under a little pressure. i took a shop vac and sucked it out till it stopped. im really confused because i've taken the valve covers off in the past and i don't remember this happening. If any one knows if the bolt hole hits into the cooling system or any other insight on this would be much appreciated.

Rev · 07-12-2006, 07:16 PM

Sounds like it's leaking coolant from a coolant passage (intake manifold to head). When you put the intake back on you needed to put a little RTV around those coolant passages. It's also easy to get the intake gasket moved into a non sealing position when you place the intake on the heads. I'm not 100% sure that this is the problem, but since you removed and replaced the intake manifold, that would be where I would look first.

Rev

dagit · 07-13-2006, 09:30 PM

well it seems like i might have an even bigger problem. somehow i have gasoline in my oil. changed the oil, ran it again and same result so i guess i really messed up the intake reinstallation. i sealed the gaskets around the head but obviously not well enough. could it be possible that the gaskets i got for it might have had the wrong port openings? idk whats going on, im gonna take the intake manifold off and see whats up tomorrow.

Rev · 07-14-2006, 04:00 PM

It's possible to get the gaskets in such a position that they don't seal at the bottom area of the intake ports. This could cause a vacuum leak sucking air from the valley area but I'm not sure if that would leak gas into the oil? Still, I suspect some kind of error in the reinstallation of that intake manifold. Take it off and look for some kind of evidence of a leak. You only use the RTV around those water jacket passages, not on the the intake port areas of the gasket.

My bet is when you remove the intake manifold you will see the problem. Let us know how it goes. If it's any consolation, I've had similar problems myself in the past and it was just a simple screw up on my part when setting that intake down onto the heads and misalligning the gasket in the process. Let us know how it goes.

Rev

Gearhead999 · 07-15-2006, 07:43 PM

Are you sure that the fuel pump, if you have a mechanical one, isn't ruptured. This will pump fuel into the oil.

Also, a carb. with high float level [flooding] will flood gas into the oil.

I've never seen an intake leak cause the gas in the oil. If the gasket isn't sealing at the cylinder heads. Well you'll have a vacuum leak and it will run terrible and won't want to idle.

I'd check the pump and carb first. Just my $.02.

dagit · 07-15-2006, 11:00 PM

Quote:

Originally Posted by Gearhead999

Are you sure that the fuel pump, if you have a mechanical one, isn't ruptured. This will pump fuel into the oil.

Also, a carb. with high float level [flooding] will flood gas into the oil.

I've never seen an intake leak cause the gas in the oil. If the gasket isn't sealing at the cylinder heads. Well you'll have a vacuum leak and it will run terrible and won't want to idle.

I'd check the pump and carb first. Just my $.02.

yea actually thats exactly what it was. the fuel pump diaphragm was busted so i replaced the fuel pump and solved that problem. i also replaced the distributor cap and condenser and shes running pretty good. as for coolant coming out of the bolt hole, im thinking someone might have re-tapped the hole right into the water jacket, but im far from sure thats what it is. im thinking that the intake is ok for now.

Gearhead999 · 07-16-2006, 02:38 PM

Glad to hear you fixed the fuel leak.

On the coolant leak. Are you sure the coolant is coming out of the threaded hole?? If it is....why don't you just seal the threads on the valve cover hold down bolt that is in question.

If that fixes it you could just leave it or.....you could thread an allen set screw, with the threads sealed, down recessed in to the hole. Then put a shorter hold down bolt.

07-12-2006, 04:00 PM	#1
dagit Registered Member Join Date: Nov 2005 Posts: 5	Coolant leaking out of valve cover hole? i just recently started giving my 68 289 some needed attention. it needed a new carb. so while i had it off i took off my intake manifold and repainted it. after reassembling everything its been like 4 months since she last ran. well i got her started today and it sounded rough. there was a little bit of clacking so i decided to take off the valve covers and spray some lube to try to get the valves from sticking. well as im unscrewing the front bolt of the valve cover coolant started to come out of the hole! Im getting freaked out thinking i blew a head gasket or something but theres no coolant in the oil. also it was coming out like it was under a little pressure. i took a shop vac and sucked it out till it stopped. im really confused because i've taken the valve covers off in the past and i don't remember this happening. If any one knows if the bolt hole hits into the cooling system or any other insight on this would be much appreciated.

07-12-2006, 07:16 PM	#2
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Re: Coolant leaking out of valve cover hole? Sounds like it's leaking coolant from a coolant passage (intake manifold to head). When you put the intake back on you needed to put a little RTV around those coolant passages. It's also easy to get the intake gasket moved into a non sealing position when you place the intake on the heads. I'm not 100% sure that this is the problem, but since you removed and replaced the intake manifold, that would be where I would look first. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

07-13-2006, 09:30 PM	#3
dagit Registered Member Join Date: Nov 2005 Posts: 5	Re: Coolant leaking out of valve cover hole? well it seems like i might have an even bigger problem. somehow i have gasoline in my oil. changed the oil, ran it again and same result so i guess i really messed up the intake reinstallation. i sealed the gaskets around the head but obviously not well enough. could it be possible that the gaskets i got for it might have had the wrong port openings? idk whats going on, im gonna take the intake manifold off and see whats up tomorrow.

07-14-2006, 04:00 PM	#4
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Re: Coolant leaking out of valve cover hole? It's possible to get the gaskets in such a position that they don't seal at the bottom area of the intake ports. This could cause a vacuum leak sucking air from the valley area but I'm not sure if that would leak gas into the oil? Still, I suspect some kind of error in the reinstallation of that intake manifold. Take it off and look for some kind of evidence of a leak. You only use the RTV around those water jacket passages, not on the the intake port areas of the gasket. My bet is when you remove the intake manifold you will see the problem. Let us know how it goes. If it's any consolation, I've had similar problems myself in the past and it was just a simple screw up on my part when setting that intake down onto the heads and misalligning the gasket in the process. Let us know how it goes. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe Last edited by Rev; 07-14-2006 at 06:05 PM..

07-15-2006, 07:43 PM	#5
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Re: Coolant leaking out of valve cover hole? Are you sure that the fuel pump, if you have a mechanical one, isn't ruptured. This will pump fuel into the oil. Also, a carb. with high float level [flooding] will flood gas into the oil. I've never seen an intake leak cause the gas in the oil. If the gasket isn't sealing at the cylinder heads. Well you'll have a vacuum leak and it will run terrible and won't want to idle. I'd check the pump and carb first. Just my $.02. __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

07-16-2006, 02:38 PM	#7
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Re: Coolant leaking out of valve cover hole? Glad to hear you fixed the fuel leak. On the coolant leak. Are you sure the coolant is coming out of the threaded hole?? If it is....why don't you just seal the threads on the valve cover hold down bolt that is in question. If that fixes it you could just leave it or.....you could thread an allen set screw, with the threads sealed, down recessed in to the hole. Then put a shorter hold down bolt. __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

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