Does block seal work for an external cylinder head water leak?

Hi All,

Anyone have any experience on the block seal product? My cylinder head has a small external water leak. Do you think this will work? I really appreciate all your advise. Thanks Termboon

I had a small leak by on of my spark plugs, and I added a small bottle of Aluma-seal. I has been fine for years. I disassembled and refurbished the engine and never did find where the leak was coming from. I'm not sure how "Big Brother" knows what the topic is, but there's an ad at the bottom of your post for Steelseal with a lifetime guarantee for blown head gaskets. Sounds like similar stuff. Easier than an engine rebuild, and it might just work.

Have you tried retorquing the head?

GM makes a good sealer they use in their crate engines. I have seen it used in an MGB for a head leak,
it works. Don't recall the name of the sealer but any GM dealer parts department should have it.

Clifton

About any cooling system stop leak will work in your situation. Alumi-Seal should work for you too, it's a very small package amount, the product is as old as dirt, and I've never heard a bad comment about it.

About three years ago (maybe 4), I had a the familiar crack somewhere above the #2 plug. I tried one of those products highly touted for fixing that kind of leak. I can't remember for sure, but I think it was steel seal. It was guaranteed to fix blown gaskets and the supplier said they frequently used it on large bulldozers.

I bought a can, put it in with the water as directed, they ran the engine up to the recommended 200 - 220 degrees. This product was supposed to activate at that temperature. First can didn't help at all. I called the supplier and under his direction, applied a soldering torch directly to the leak area. Still no affect. They sent me a second can free. Tried same procedure, no luck.

I would up buying a crack free head from a forum member. No further problems.

I had looked at a lot of options before buying the good head, including welding and some other "mechanical" fixes.

I don't mean to slam Steel Seal (if that was the product). It probably works very well in most applications. It just didn't in mine.

Good luck.

I too have used the Alumaseal but did`nt put in the whole container,I used about 1/2 of the tube or bottle and mixed it real well with prestone/water 50-50 and it stopped up a leaking radiator.

While I respect the opinions of many in the group, when it comes to adding these chemicals to your cooling system, I have to respectfully disagree with the consensus here.

Termboon, I strongly suggest NEVER putting any stop leak into your cooling system. Stop leak is not permanent, its just a stop gap, it doesn't know a good hole from a bad hole and will cause your cooling system to become less efficient. Stop Leak is a short term fix that leads to long term problems. While many times it does temporarily stop the small leak, it is also all throughout the cooling system once introduced.

If you want your rad to work efficiently and your head and block to cool efficiently go ahead and fix the leak properly. Once these chemicals are introduced they tend to cling to the good clean surfaces of the radiator, and cause these surfaces to disapate heat LESS efficiently causing long term overheating issues.

I assume we're still talking about the little seapage from your cylinder head.

Can you post a very detailed close-up and overall pic of the leak in question. Hopefully then the group can advise on what steps need to be taken to fix the leak properly.

While many on here will definitely advise on the usage of these types of chemicals, i have found them to be nothing but TROUBLE down the line. AND, they're NOT permanent, so, it'll be more stop leak in a few months and then each introduction of these chemicals will cause your cooling system to become less and less efficient.

Fix the leak properly and enjoy many years of efficient cooling of your MGB engine.

Brian

Wow Brian, I was beginning to think I was the only one who opposes the use of such sealants. A little internet surfing will tell you at best its a temporary fix and it also can plug up the rad cores and heater cores. They used to put an egg white in the rad to stop a leak and it worked for awhile but its not a permanent fix IMHO.

9 out of 10 MGB heads are cracked due to a factory flaw which creates a void leading to a steam pressure crack between to valve seats. The pros drill and tap a hole and use a set screw. This allows filling the engine with water and nulling the void.
I'm thinking if you have water leaking out the head, you probably have a bigger problem below which needs inspection sooner than later also IMHO.

Good luck!

I'm not a fan of "monkey snot" miracles in a bottle either, but...

Like Clifton said, GM offers a product that they stand behind for similar issues. As does Subaru and probably every manufacturer out there.

I have read discussions of how they work and they are not supposed to "catalyse" unless they come in contact with particular conditions, heat, oxygen, combustion gasses, what have you, there are a few different products out there. Using the wrong one will not help and could make matters worse.

I'm in the "not likely to be any worse off" camp.

I think if Ternboon offers up a picture of exactly where the leak is, we can all offer a solution to the problem very easily.

so many people complain of non-efficient cooling systems in their MGBs and its my belief that 90% of the problems are from clogged radiators and water jackets. Ive seen that radiator snot clog completely the channels that are in a radiator, and the more channels that are clogged, the less chance the water has to dissipate its heat.

Pepper will also work in a pinch, it tends to go right to the hole. The good thing about pepper is that you can get it out of the system later, and it smells like a BBQ while driving! hahahahahaha

See if you can post a close up picture as well as one back a little further to show orientation.

There is so many people here that have ideas on fixing these problems, its crazy not to get their opinions.

Good Luck,

B

I stand by what I suggest. Gasoline without alcohol belongs in the tank. Dino oil with profound additives and ZDDP belongs in the oil. Distilled water and anti freeze belongs in the rad system. And Castrol fluid belongs in the hydraulic system. A departure from the tenants of LBC car suggestions maybe, could be, might have and could have adverse effects. Fluid "fixes" are a short time solution. IMHO.

Thank you very much all of you guys. Please see the water leak on picture. Termboon

Do you see the crack?

Seems to be a rash of cracked head threads lately and I was one of them. That sir is a cracked head and the most popular spot. I got three of them exactly the same. If you were to strip the head and beadblast it , you will find the crack extends across to the guide. So, if it isn't now, it very well may end up putting coolant in the oil. You can go to flowspeed.com for a picture of what it looks like exposed.

Yes GM makes coolant sealant tablets. They seemed to come available about the same time as thier 4100 Caddy motors started to blow in the mid 80s. Aluminum motor with sleeves and the seals for the sleeves would start to leak, coolant into the oil & bingo...junk motor. Big bucks to rebuild or replace so my guess is GM figured if they could extend the life with stop leak..what the heck. Supposedly the stuff works.

But, like Brian & Robert I'm not much for mechanic in a can remedys. The situation I am in is a customer car with an engine getting a complete overhaul. So the head is cracked in the mentioned area. Not aparently leaking coolant but cracked. So, only a fool would spend several hundred dollars to rebuild a cracked head in hopes it doesn't leak in the future and trash the whole rebuild.

FWIW, the professional air conditioning techs despise the stop leak products too. They are designed to harden when exposed to moisture or air. Only problem is with an old system, those two can be present in the system itself. So the crap hardens in the condenser, lines, evaporator ect and the whole system is junk.

Termboon,

I am sorry to say, if your engine is running and you see water seeping directly out of the side of the cylinder head there, then you're gonna have to replace the cylinder head.

Ask the group here for help, there are quite a few, like basil and the others that have good used heads lying around for the group to take advantage of.

Unfortunately, you're soon going to, if not already going to have that water seeping into the cylinder and into the oil. That is very bad!

Get yourself a used head and have them fix it up for you. Then the group will help you install it. It is very easy Boon, very easy! No worries!

No amount of stop leak will fix that problem. It will only jam things up!

You're lucky to have this group, and to be able to take advantage of the wealth of knowledge and parts!

I wish I had a better fix for ya, but, if you're seeing water seeping right out the side and not running from somewhere else, then that crack goes way back into the head, and will be nothing but a source of headaches and further damage to the whole engine. Luckily, there is a good supply of used heads here amoungst the group!

So, somebody help Termboon out here with a new head!

Good luck buddy,

Brian

When you buy a head ask the seller to magna flux it and offer to pay it it checks out. Better if both buyer and seller know the issues. As mentioned, people who rebuild these professionally find about 90% have the crack we are discussing.

I had the head off a BMW 500 series that was blowing coolant out the exhaust. It turned out to be a crack leading from the exhaust valve seat to the coolant passage. A new head was outrageously expensive. The local machine shop was able to insert several plugs into the crack after drilling out small holes for them. He then machined them flat. When I reinstalled the head it didn't leak a drop and has been running fine for several years now. Worth looking in to. RAY

That procedure is called stitching. Almost a lost art but about as simple as you describe. Each stud is slightly overlapped and drilled and tapped again and again until each end of the crack is "pegged". It what folks with very high end and rare cars have had to do and what was done when the first cars had such issues....
The cost however isn't practicle for an MGB IMHO.

As Robert says. Plus the crack we are looking at here runs all the way in to the guide. I would bet money on it. So you would be looking at repairing roughly an inch & a half maybe two. That would be a LOT of stitching.

Again, I refer to someone with MUCH more experiance than me. Sean Brown's website has photos of all the crack areas and any feasable repair procedures...which are not many.