External Head Gasket Leak

[Bill Braun]

Eric,

I have a small external head gasket leak on my 1988 Celica GT Convertible. I have attached a picture of the leak highlighted with leak detector/UV.

I have tried to fix the leak with Bar’s Leaks Cooling System Radiator and Heater Core Stop Leak. I have by-passed the heater core.

I can identify the exact location of the leak. After a 15 minute drive, using a uv light I can see bubbling of coolant at the point of the leak. I appears that the remaining leak is pin hole or slightly larger in size. Once the engine has cooled I have done radiator leak down tests and it is much better. After 12 hours the tester gauge has only dropped about 5 pounds of pressure.

Is there any product that I can use to seal the head gasket leak externally?

Any other suggestions…. please

Thank you for your help.

Attachments:

• ExternalHeadGasketLeak.JPG

Topic

[Bill]

Bars Leak is one of the worst products I have ever used. It damages hoses and plugs up radiators and heater cores as well as vital coolant passeges.

In my opinion there is only one way to repair your problem and that’s to replace the head gasket.

[Trent “Teddy” Martin]

Wysetech is right you’ve probably now done more damage by trying to find the easy way out then what it’ll cost you for the headgasket replacement alone. When it comes to cooling systems there is no easy way out just replace the parts needed.

[dan]

well along with wysetechs statement i agree with it, stop leak is only a temporary get you home in a emergency fix, and can have nasty reporocutions and should only be used if absolutely necessary! the only action is too replace the head gasket…

Eric will tell you the same thing.

[EricTheCarGuy]

As pointed out, I don’t recommend the use of stop leak products to cure leaks like this. They can work however if used properly. That said, you might consider removing the valve cover and retorquing the head bolts to see if that helps the problem. Outside of that, you may need to remove the cylinder head to replace the gasket.

Good luck and keep us posted.

[Bill Braun]

Eric,

I am trying to take this slow… I have never gotten in to taking an engine apart and I appreciate your help. Thought I would check to be sure the head bolts are tight.

Removed valve cover. Looks like next step is to remove both cam shafts. I assume I have to mark them some way so when I put them back in they are in the proper orientation. Am I correct and how do I do that? Will the cam shafts just lift out once the retaining bolts are removed?

FYI: I did a minimum price check with two shops. One was $1100 and one was $1800. Seems like a lot to me for a 4 cylinder engine.

I checked online with a auto repair cost estimator and the range there was $800+ (Dealer) to $500+ independent shop.

I really appreciate your help. I want to learn more about how to do this…. Money is not the issue. I am a DIYer, am retired, have time and enjoy learning how to do new things.

Thanks,

Bill

[Bryan Carter]

On some OHC engines the head bolts can be accessed without removing the camshafts. If you do have to remove the camshafts to reach the head bolts, you might as well go “all in” and just proceed with a head gasket replacement. No sense in spending hours attempting something that may fix the problem when you can spend just a little more time and do something that will fix it.

[EricTheCarGuy]

On that engine you want to be careful removing the cam shafts as I believe one of the gears is split that drives the other cam. This gear is spring loaded and if you just remove it, the tension will be lost and you’ll have a bunch of engine noise when you put it back together. The way you prevent this is to install a bolt in the threaded hole in the cam gear before you remove it. This will help maintain tension on the gear and prevent it from loosing tension.

Once you remove the retainers as you suggest, you should be able to lift out the cam shafts as you suggest. You may also need to remove the distributor as well. As you stated, you want to mark everything before you remove it so it get’s back in time correctly. From there it should just be a matter of torquing down the head bolts. This MIGHT help, to be honest, I’m not sure. You may end up having to replace the gasket in order to fix the leak.

It would be great if we could get ToyotaKarl to weigh in on this one. He may know if this is a common problem and what the fix is.

[Bill Braun]

Interesting about the split gear. I read this after I removed the exhaust cam (the one with the split gear). It did not come apart or move …. I did mark the cam gear matting points with “white out” so that I could properly re-install it. I guess I was lucky…

Once the exhaust cam was out I was able to check the head bolts on the front of the engine and they were tight.

I will update as I continue to try to fix the (now) smaller leak.

I did contact JB Weld about the possibility of using their products to externally seal the head gasket leak. Here is their reply:

“JB Weld has had many customers use our products on their head gaskets with success. If you have the time and patience and could apply the Original JB Weld epoxy, I would use that product instead. With a temperature resistance up to 550 degrees and a 3960 PSI rating it is stronger and has a higher heat resistance than our putty product called High Heat. If the application is too difficult to apply this more liquid epoxy the next best option would defiantly be the High Heat product.
Cleanliness is important in the application process with our products. The cleaner the better. All of our products, once fully cured, cannot be taken off with any type of solvent. Burning and grinding are the only ways to get our products off of the surfaces, hints the “World’s Strongest Bond”.
I hope that I have assisted you in your application of our product. If there is anything else I can do for you please let me know.”

Bill

[Bill Braun]

Eric,

Still working on this external head gasket leak. Do you think that a product like Hondabond applied at the point of the leak may stop this leak?

Thanks.

Bill

[Bryan Carter]

As a general rule you want to stop coolant leaks at the source, not the destination.
The problem is that even if you do seal the external leak, you’ll be left with a pocket of coolant trapped between the head, gasket, and block. That’s not good. The trapped coolant will attempt to flash over to steam and look for an exit. If you’re lucky, it’ll head back to the water jacket it came from. If you’re not lucky, it’ll further erode the gasket and either make a new external weep hole, or worse yet, head for the nearest oil passage or cylinder bore. Then it’s game over.

[Bill Braun]

Eric,

Thank you for the explanation. I am prepared to replace the head gasket if a simple fix doesn’t work. When you say “game over” I assume you mean that I will have to replace the head gasket.

Bill

[Author]

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