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Hey there community,

I *just* got my rig together after a frame up rebuild... Fired up and took it for its first spin without issue, other than this smallish leak. It's out of the bolt head between spark plugs 4 & 5...Wondering if anyone has some insight? It was torqued down solid when the leak appeared, then I pulled it, added a rubber washer, but this made no difference... This is one of the bolts that should hold the extraction loop, which I have, could it not being on there contribute to this leak? Help!

Did you apply sealant to the bolt threads when you installed it? If not, you should pull all of the bolts that go into the coolant passage and seal the threads. The other ones will probably start leaking, too.

Just curious: how did you torque that leaking head bolt with the rubber washer in there?

You need thread sealant on all the bolts that pass through a water jacket.

but the threads are only on the lower portion of the bolt - and there is a water reservoir above them (unless there shouldnt be!) so how would thread sealer help? .... and no - there wasnt any on the threads....i attempted to figure out the routing of the water system by the TM wasn't super clear....basically, i pulled the bolt, with the coolant full, and it fountained out due to the height of the top of the head vs. the radiator height...

thats nuts
I don't run sealer just anti seize and have never had a problem. however I have been warned of this happening if sealer is not use...... hmm... are those used head bolts and could it be wasted and pitted? are you running washers under the head bolts?

...so im still not clear on how thread sealant would help to avoid this problem...as there is coolant above and below the threads....see pic.....seems to me it would have more to do with the bolt head not mating perfectly to the washer, then to the head....? is there more pressure in the block than the head? im happy to pull it and seal the threads - just not sure that will sort out the problem - the bolt is surely not in new condition, so there could be some pitting on the non-threaded section of the shaft...

The coolant is coming around the threads of the bolt from the block. The coolant system is not open around the bolt hole in the head. Seal around the threads into the block and the leak should stop unless there's a crack in the head at the bolt hole.

While were sealing threads, don't forget the ones on the front face of the engine. Mine didn't get sealed and I had to pull the motor back out (mostly) to redo them.

Good luck! & More pix!

-jim lee

7 weeks since sandblasting, outside, in the snow....