Coolant system sealer

[Lenz]

So, I was checking my throwout bearing clearance and noticed something out of the corner of my eye.  An almost imperceptible coolant leak from bottom of the tin between the bell and block.  Checked topside and found no evidence anywhere.  At this point assuming a small weep from a freeze plug (?) Oil and coolant are clear, no external evidence of gasket failure.  Motor has about three hours of operating time on it and is running strong.

Read in one of Jay's recent posts about running sealer through the engine to make sure there were no coolant leaks.  Is there a preferred type or Do I just hit it with "Bars-leaks" or a similar .

As always, input appreciated-  Len

[My427stang]

They all work pretty well, considering nobody admits to using them

I have had good luck with the old school pelleted/syrup Bars leaks in the clear bottle.  Best bet is to warm it up with the cap off, then dump it into hot water and close it up

[cjshaker]

Ok, somebody.....what could possibly leak coolant between the block and bellhousing? Only thing I know of back there are oil hole plugs and the cam plug, none of which have coolant near them.

Are you sure it's not coming from the head and seeping in between the bell?

[Lenz]

Ok, somebody.....what could possibly leak coolant between the block and bellhousing? Only thing I know of back there are oil hole plugs and the cam plug, none of which have coolant near them.

Are you sure it's not coming from the head and seeping in between the bell?

Short answer, no.  I should have remembered no plugs back there , guess I had a vision of one of those "other" blocks stuck in my head when thinking about possible sources.

I ran my hand across the intake base, intake/head interface, and around the base of the heads at the block near the rear, all bone dry.  Will check again tonight and move forward up the block.

Problem is that it's minor enough so as not to present itself.  I pulled the cap and the coolant level was about an inch down.  If I hadn't been under the car I wouldn't have noticed it.  That's why I thought of a sealer. 

[LargeRickhead66]

I had a similar trace leak that turned out to be a head gasket leak, they were Felpro 1020s ,since it was a pretty fresh rebuild I re-torqued the heads and that problem was solved.

[Lenz]

Yeah, they're Fel-Pros and this build is plenty fresh.  When I assembled I torqued, did something else for an hour and then torqued again.  I also pulled the valve train and torqued again (along with "snugging" the intake) after initial breakin was done.

Even with all that it makes sense to check again though, the only real choices are heads or intake.

[fe66comet]

I don't use the sealer due to the coating it leaves on the internals. The radiator is the most prone, along with the heater core. I have had to actually replace plugged heater cores and radiators from it. You loose a lot of cooling capacity, kinda like a heat blanket.
.

[Bolted to Floor]

I have used a Vighty Vac pump for vacuum / pressure to pressurize cooling system to find the pesky leaks. I try to keep it around the cap rating on pressure. Good luck 

[fe66comet]

That's a good idea, I always borrow my buddys pressure tester but I have a Mighty Vac already.

[66FAIRLANE]

I have used Moroso Ceramic sealer for small weeps with success.

[fastback 427]

X2 on the moroso sealer. It sealed two different head gasket leaks for me.

[cammerfe]

For many years, Ford was said to put Bars-Leaks in every new car coming off the  assembly line.

KS

[turbohunter]

For many years, Ford was said to put Bars-Leaks in every new car coming off the  assembly line.

KS

At first I was surprised by that, but after thinking about the ratio of motors lovingly put together by us that leak vs the amount of motors Ford put out that don't leak, it makes sense.
I'm trying to get over the personally perceived stigma of using the additive as a crutch for inadequate work/parts.

[rcodecj]

I quit using bars leak years ago when it plugged my heater core.
I started using aluma seal with great results.

http://www.amazon.com/AlumAseal-ASBPI12-Radiator-Powder-Blister/dp/B000FW61M4/ref=sr_1_1?ie=UTF8&qid=1405793972&sr=8-1&keywords=aluma+seal

[Lenz]

Marc, get what you're saying about the quality of work and parts.  I was careful and can remember each step of the assembly process due to habitual triple checking and still ended up in this spot. Even so, sealer is where I'm headed 'cause I'm good on the torque and there's no way I'm going back into the motor to figure it out without trying the easy path.  Thanks for the input all, very informative as usual.  I'll follow up after I do the deed.