re-seal a leaking head gasket

I heard of a solution that is ran through the radiator to repair a leaking head gasket.
Apparently, you let it sit over night to set and it can fix the leaky gasket.


I recently overheated, been throwing 0300s, and predominantly 0301s.
At first, I heard a loud bang as it overheated, but figured it was a backfire.
Do blown head gaskets make a loud bang?
Put in a new radiator and thermostat, and had a rough idle.
It seemed to go away at higher RPMs.

Drove it for 100 or so miles, and the rough idle has gotten much worse.
Cleaned the IAC and Throttle Body.
New cap, rotor, plugs and wires.
Swapped #1/#6 plug and wires, 0301 remained.
Pulled the #1 injector, found evidence that it was gunked up a bit with coolant.
(maybe oil too)
Replaced the #1 injector, codes have gone away, but have only driven 5 miles or so.
Drives very rough with loss of power, blows a little blue smoke and smiles of coolant.

Although I would like to minimize the cost of getting up and running again, I don't have a lot of faith in this 'miracle solution'

Bottom line, I have coolant in my #1 cylinder.
This stuff you run through the radiator is potentially a cheap fix, but is it very viable?
Any advice?

1997 XJ 4.0 150k miles.

No, and it's very likely to muck up the rest of the system.

I'd only put it in if I was trading it to a dealer 10 miles later.

As long as your head is not cracked the gasket is not terribly expensive, and it's something you can do with the motor in the Jeep, about the only special tool you'll need is a decent torquewrench.

Thanks that's what I thought and how I felt about the re-sealant gunk, too.

I agree with 87manche, I believe the best way to re-seal a leaking head gasket would be to remove it and replace it with a new one.

Not too big a deal really, before you get started get a long 1/2" twelve point socket that will fit over the driver's side head bolts...check it before you start...that way you don't have to bum a ride 3 times to get different 1/2" sockets that don't fit...ask me how I know!

I'd run a compression test on all cylinders to help verify this diagnosis, but it very well could be the headgasket.

I'm not a big fan of the headgasket sealer that is sold. It might work for a small leak but it can have some bad side effects.

If the headgasket is bad, I'd get a new one in there. Not as easy as changing your spark plugs, but this repair is do-able for most people with reasonable mechanical skills.

It is possible though that the head itself is cracked. The head on the 97 isn't as susceptible to cracking as the 0331 cylinder head found on the 00-01, but any head can crack when overheated.

So if/when you remove this head, I would highly recommend that you take it to a machine shop that specializes in this and have them verify that there are NO cracks in this head. (pressure test/magnaflux) This won't cost you a lot and is really money well spent. You really don't want to go through this repair twice.

Don't delay on this repair. Coolant and oil makes for some really fast engine bearing wear.

What if I want to gunk up my radiator and the rest of my cooling system?

: )

These aren't the droids you're looking for.
Move along, Move along.
Nothing to see here.

I was just wondering if you guys had heard of that stuff.
Of course the proper thing to do is replace the gasket..

This morning when I posted this, I found myself between a rock and a hard place.
New management won't let me work on the Jeep in the parking garage anymore.
Although this would be a big job for a shade-tree mechanic like myself, I just had it apart to put in a new exhaust manifold a month or so ago.
Not much more work involved for the head gasket - I'm sure I could do it.

Had to take the Jeep to a mechanic though, and these Canadian hourly prices are insane.
The guy mentioned this 're-sealing stuff' and I had never heard of it and wanted to ask the forum, after turning up a bunch of nothing in my searches.

I'm sure you can all relate to doubting a silver bullet, but wanting it anyways!
Feels good to get affirmation from you, my friends!

On the bright side, I'll get the head pressure tested instead of just slappin it back on!
$$$ if you wanna play, you gotta pay.

kndrewa said:

$$$ if you wanna play, you gotta pay.

Click to expand...

You are correct sir. Any vehicle that is 14 years old is going to need a repair once in a while! :cheers:

Get it checked for flatness as well. Maybe put on a new freeze plug while it's accessible. Use the spiral torque sequence taking it off(sequence in reverse) and putting it back on(tighten in stages), use sealant on the driver's side front corner bolt(and note that it has a lower final torque than all the rest). The only bolt that is difficult getting to(that ledge is in the way!) and a little tricky getting back in(put it on head 1st) is the one the firewall ground strap goes to.

I had a 98 Mustang GT with a 150 shot and blew the driverside headgasket. I used some brand of ceramic block sealer and the car was fine for an entire year. I then sold it to an X and it promptly blew up on her. :clap:

But for the 15 bucks it cost, a year is pretty good for unicorn boogers.

I had a 1994 wrangler that blew the gasket on it. I used the stuff and it lasted another 2 weeks and the gasket blew again. I think if the leak is small it would work but probably more as a temp fix. Its probably just remedying the problem for the moment but I wouldnt count on it lasting too long.

I am quite the fan of snake oil repairs, including head gasket sealant for coolant leaks (very small ones), but from the sound of it, you would need the heavy duty stuff, which I would not use, and it probably would not work on a leak that is that bad. Go straight to a new head gasket or engine swap IMHO.