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New rebuilt 383 hp block

66belveder

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Just had 1968 383hp block rebuilt, I believe head gasket is leaking, my first question is does the head bolts us any sealer on them or are they just installed dry???? with no sealer. There is no anti-freeze in oil, Anti-freeze is leaking out between head and block under # 4 & 6 exhaust header tube.
Which head gasket should I try to use next when I pull head off???? I'm using stock head bolts also, should I use a washer on the bolt just to make sure I'm bottoming out head bolt??? I'm just thinking about just pulling both heads replacing gaskets and use new ARP bolts, engine does not even have 5-minutes of run time on it, not to dam happy with the builder right now but before I clime up some body's you know what . ANY SUGESTIONS FOR FIRST TIME MOPAR OWNER WOULD BE HELPFULL, THANKS **heads were also redone by different person do I send them back to have them rechecked** The first time I do not dyno a engine or run on engine stand it leaks, never again will that happen again
 
some of the exhaust header bolts go into water jackets and need to be sealed
 
X2 on sealing exhaust manifold bolts. The factory used studs which rarely gave any problems.
 
The head bolts don't get any sealer, just a very light dab of oil. On stock heads, you will need to use a sealer on the exhaust bolts. Are you sure the freeze plug isn't leaking?
 
Mine also leaked when I changed cyl heads and put headers on. I also thought at first the head gaskets were leaking. But I drained the coolant, and wrapped each header BOLT with 9 turns of teflon tape, and installed them. That solved the problem. 2 years later and still holding. In place of the end bolts on each head I used an ex stud so that the header gasket would stay in place when I put the bolts into the remaining holes. Try this fix before going to the time and expense of pulling the heads back off. I use steel shim head gaskets on all my engines. And for sealer I have used aluminum spray paint, and lately spray a gasket copper coat. Never any issues.
 
hi 66belveder im no expert but as the other post reads sounds like header bolt leak at least 2 bolts-studs each side are wet -go into the water jacket just went thru this drain the coolant first i used.high temp permatex THREAD SEALANT i cleaned the bolt hole with a Q tip sprayed wet with brake cleaner went thru a hand full of q tips till clean then buttered the the bolts up and installed them no more trouble hope this helps you PS I FOUND OUT how to do this by reading old posts thank god for this i love this site it has really helped me a lot thank you to all members
 
Those 2 ex bolts below # 4 and 6 header tubes definitely go into a water jacket .
 
Thanks, but I know about header bolts and yes I use studs on the ends, I have taken header bolts out 4 different times, cleaned them and reinstalled them using RTV silicone sealer, Do you think since I doubled up header gasket it could be causing leak, I used same of driver side head, double header gasket and same kind of sealer and it's not leaking on that side
 
I have doubled the gaskets before with no problem. Have even repaired exhaust bolt hole threads with coil inserts gupped then with silicone and inserted header bolt with no sealing problem. If your headers will allow it try studs at 4&6.
 
I would remove the header, seal the holes, and see exactly where the leak is coming from
 
I would remove the header, seal the holes, and see exactly where the leak is coming from
Let common sense prevail! Eldubb440 motion has been second'd. All in favor say "AYE!"
The art of troubleshooting is to break the puzzle apart into manageable pieces. Removing the exhaust for troubleshooting purposes will let you get a visual on the source of the coolant. Theoretically, it could even be caused by a porous section in the casting. No amount of gasketing or sealing of bolt threads would fix that. Only when you know the source of the leak can you put a thumb in the dyke.
 
Thats a great idea! Plug the 3rd and 4th ex bolt holes and then check for leaks. Maybe even plug them all. Isolate the problem then fix it.

- - - Updated - - -

I don't care for the orange hi temp sealer for the bolts. Is that the type you used? Its messy, and teflon tape is easier and makes a cleaner installation.
 
AYE and yes I used the orange hi temp. Would have used teflon had it not been for the coil inserts used to repair threads.
 
Suppose you already know not to run the engine without exhaust manifolds on, right? Why? Exhaust valves need at least 6" output to get the flamefront away from the valves, or they will get burned.

You might be stuck using teflon tape, unless you drain some of the cooling system, to get the water out of the heads. I usually use Indianhead shellac sealer, but of course, things need to be dry.
 
Suppose you already know not to run the engine without exhaust manifolds on, right? Why? Exhaust valves need at least 6" output to get the flamefront away from the valves, or they will get burned.

You might be stuck using teflon tape, unless you drain some of the cooling system, to get the water out of the heads. I usually use Indianhead shellac sealer, but of course, things need to be dry.
That's a good point. The time it takes to heat up the block could allow some cold air surface cracking of the hot valves. As well, the toasted wire harness that's inevitable. Hmm. Maybe not the best plan after all. Perhaps a cheap Horror Freight (Fright?) bore scope viewer. A trick is to dry it out and apply a coat of talc powder or chalk to follow the source visibly.

Also, a good point about the RTV not ("ever") sealing to a wet surface.
 
Thanks, but I know about header bolts and yes I use studs on the ends, I have taken header bolts out 4 different times, cleaned them and reinstalled them using RTV silicone sealer, Do you think since I doubled up header gasket it could be causing leak, I used same of driver side head, double header gasket and same kind of sealer and it's not leaking on that side

One might want to check for a hairline crack in head near your leak area. I had a similar situation once and had to replace head because of a hairline crack near exhaust mounting bolt hole. Don't know if you had heads magna fluxed before rebuild, but it is possible they missed it.
 
Back in the 70 the USAF would not allow use to have sealants in the shop. We sealed everything with wheel bearing grease we could even head gaskets.
 
Best thing to do on a water leak, and find it's source, try to rent a cooling system pressure tester. Need to find out exactly where the coolant is leaking, and fix it.

But, if you have bolts mounting up the exhaust manifolds, won't do any good to pull 'em. Side note, typical, my 906 heads are open to the water jacket at ALL stud holes. Suppose year makes the dif.

RTVs...personally, don't like any of it. Guess it's the old guy in me.
 
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