Coolant leak between cylinder head and block. Why?

94califiveoh · Mar 29, 2010

I fired up my mustang after a fresh h/c/i swap and noticed there was a significant amount of coolat leaking between the driver side cylinder head and the engine block. It almost looks as if its coming from the cylinder head bolt. I know for a fact that I torqued the heads properly but now I dont know why theres a leak. What do you guys think could be causing this?

hottwheels04 · Mar 29, 2010

you have a crack in your head gasket prob when you put them on you might of over torqued the head bolt and cracked the gasket just enough so its leaking coolant.

modo · Mar 29, 2010

did you put the thread sealant on the bolts that go into the water passages? if not that is your problem

.02

94califiveoh · Mar 29, 2010

After doing some research, I was unaware I needed thread sealant for the bolts that go inot the water pasages. Do all the lower bolts need them? or should I just do it to this bolt that is leaking? can I unbolt just that one bolt or will the head warp?

OnyxCobra · Mar 29, 2010

did you take notice to put the head gaskets on the correct way? There is a front and rear to them.

94califiveoh · Mar 29, 2010

yea, I made sure the head gaskets were installed properly. I read of horrible stories with improperly installed head gaskets

OnyxCobra · Mar 29, 2010

Then yeah it could be the bolts that go through water jackets need sealant... otherwise not too sure.

Blind · Mar 29, 2010

all of the lower bolts need thread sealant, did you chase all of the head bolt threads with a tap to clean out the old sealant? If you don't, the torque reading when bolting them down won't be accurate.

94califiveoh · Mar 29, 2010

They are brand new TFS heads with new ARP head bolts. I used the supplied assembly lube from ARP to torque down the bolts. But Can I unbolt, apply sealant, and bolt in each bolt, one at a time?

Blind · Mar 29, 2010

you need to tap the threads in the BLOCK to clean out the old sealant so the threads are clean, has nothing to do with the heads or bolts.

it's a gamble at this point, but worth a shot.

rz5.0 · Mar 29, 2010

you can try that cause if you pull the head youll need new gaskets. been there i actually had to tear mine apart cause a head gasket was on backwards. it sucks extra 120 just on gaskets, and a new radiator on the way.

94califiveoh · Mar 29, 2010

well, at this point Im worried the heads will warp since they have already been through a heat cycle. I think I should play it on the safe side and just go ahead and tear the damn thing down again, remove the cylinder heads, install new gaskets, and apply sealer to the head bolts. idk, at this point this thing is frustrating me...

OnyxCobra · Mar 29, 2010

I read somewhere that said as long as the coolant ports are okay on the head gasket you could reuse it, seems risky though but if you just need to unbolt your head and reinstall it i don't see why you'd need new head gaskets.

94califiveoh · Mar 30, 2010

If I dont get a response from here and the other forums, I guess i'll be the lab rat and test out if pulling one head bolt at a time will work. i'll give it a few more days for people to post...

modo · Mar 30, 2010

man yank the bolts on the corners as they are the ones with the water passages. put some good teflon thread sealant on them and the thing will be fine

94califiveoh · Mar 30, 2010

ok, I think im going to just do that. the guys from the other forums are also telling me that I should be fine with it.

MODO, so I only have to the the bolts on the corners? or is it all the lower bolts?

wannaboost94gt · Mar 30, 2010

Clue me in on what you guys are referencing as the lower bolts? :tard:

modo · Mar 30, 2010

94califiveoh said:
ok, I think im going to just do that. the guys from the other forums are also telling me that I should be fine with it.

MODO, so I only have to the the bolts on the corners? or is it all the lower bolts?

its the lower bolts... not just the corners, sorry about that. the short ones.