I just put my engine back together last night and had a chance to run it for a longer period of time today. There appears to be a coolant leak at the base of the cylinder head, i.e. where the block and head meet. It doesn't look like it's leaking through the bolt hole; the coolant seems to seep from where the head gasket would be. It's enough of a leak to cause a small pool of water on the ground after shutdown. That's another thing -- in my brief troubleshooting, it doesn't seem to leak when the engine is running, only when it's turned off.

Is this something that I should wait out and see if it'll correct itself, or am I looking at another teardown and reinstall?

 

Probably won't fix itself, but take a good look all over, make sure it's not seeping from somehwere above and running down and collectiong to where it's at now.

You'd be surprised at how a small, minor intake leak can curl it's way to look like something else.

 

I had thought about something other than the head leaking, but I don't see how it can be anything else. The leak is at the bottom side of the head right under the header -- I actually have to use a mirror to see where it's seeping out. There are no drip marks above it, and I actually just sat there for a few minutes and watched coolant ooze out (with the engine off).

I think I know why it's not leaking when the car is running -- it's being burned off by the heat of the header.

 

Well, if you're absolutely sure that it is leaking there, and not coming from somehwere else, you have to pull the head and do another gasket...no way around it. headgasket leaks don't get better with time, only worse.

Did you have the head checked for surfacing? The block? I just pulled a flathead apart that the head gasket was leaking..for gawd knows how long, and it actually ate a groove into the deck.

 

Yikes; I bet that flathead has seen better days...

I just picked these heads up from the machine shop the other day, freshly surfaced. I also had the block surfaced when I pulled the motor.

I just checked the head a few minutes ago and it's not leaking anymore. The engine has been off for about an hour and a half. There's still coolant in the passages; I haven't lost that much yet.

The more I'm thinking about it, I wonder if the water isn't wicking its way up the head bolts, against my first opinion. I figured that the area below the bolt's head would be wet if the holes weren't sealed properly. But, I guess that water's going to go through the path of least resistance too, emerging at the base of the head. It could also explain why it's not leaking now that the engine has cooled down -- the sealant hardened up again.

I attached a picture of the engine before assembly. The red arrow points to the area at fault, and the green shows the location of the coolant. The nearest "boltless" water jacket is still pretty far away.

The head bolts I bought did have a decent amount of sealant on them, though. Hmm...

 

Hmmn, did you use sealant? I've never seen new headbolts with sealant attached, is that what you bought? Could very well be your problem, but also, keep in mind that if one leaks now, the other will most likely do so later on.



Quickets way, if you suspect a sealant issue, would be to drin the coolant completly, then get your shopvac and pull the Tstat and suck all coolant out you can get...

Spary some brake kleen down through the head bolt holes to clean/clean anything that may not allow the new sealant (that you will be uing) to seal. Let it sit for several hours (at least) to dry so the new sealant will adhere.

When you remove the headbolts, take then off in the opposite pattern of installing them../e outside then in.

Reseal and retorque from inside out pattern.

You may get lucky.

If it were me, I'd probably be pulling the heads and getting a new gaskets in order as well.

 

Yeah, I guess it does look like I'll be preparing the heads to be pulled. Just the thing I didn't want to do...

These bolts were purchased from a local auto parts store. There was about 3/4" of white stuff on the threads of each bolt, although the directions that came with the kit said "use sealer on all bolts." Maybe the white stuff was something else?

Basically, the only sealant that I've heard used is the Loctite PST thread sealer with Teflon. I bought a tube of the Permatex equivalent, which should be the same stuff (I think that Loctite is actually owned by Permatex).

As far as cleaning the old sealant off the bolts and the holes... could I just run a tap through the holes and a die over each bolt?

 

Grrrrrr...had a long reply typed an lost my connection...

Did you clean the block when you got it back from the shop?

Machine oil will always be stuck in the threads you don't want them to be...really inhibits the sealer's effectivness.

Blow the holes out with brakekleen, gotta have a good, clean suface for anything to adhere to. After the brake kleen, blow it out with air to aid in drying it.

 

is it just me or does that gasket look really out of place? the fire ring looks to go a good inch away from the edge of the cylinder wall. perhaps just an optical illusion?

 

Nope, that's an optical illusion -- everything lined up fine when I put it together. That picture was actually taken the first time I had heads on the engine. I just didn't have a picture showing the head gasket this time around.

 

Please tell me that that was just worded badly Otherwise.... check it out, I found your problem

 

ok... that gasket is taken laying on the cylinder head right? I thought it was on the block, makes alot more sense now

 

Well, yeah, umm... . I didn't know if it was the head gasket that was bad or just coolant seeping through the bolt holes.

FstBrd6point3, that picture was taken of the block. I looked at the picture a little closer and it's actually not an optical illusion -- the head gasket bores were actually shaped like that. They were standard Victor Reinz gaskets, which were the cheaper brand. I had to pull the heads used with that gasket because they cracked (bad valvetrain geometry), but the second time I put it together (this time) I used Fel-Pro gaskets. Attached is a picture of how it looked.

 

yea, the felpro looks alot better. I have a set of the 1034 felpro head gaskets, and they hug the bore all the way around, it just looked rather odd to me. what they really need to do is make aftermarket gaskets like the ones being used in OE these days, they are about a thousandth of an inch wider than the bore all the way around... all in the name of emissions, but do an awesome job at keeping the fuel mixture where it belongs, in the chamber and not stuck between the head and block