[Dake]

Hi all, I just removed the head from my 1979 Rabbit 1.5D which blew the head gasket. To my surprise I discovered that several of the coolant passages were blocked by the head gasket. These are passages that exist on the head and block, and you can see piles of sediment where coolant was unable to get through and just sat there.

This is the first time I've ever had the head off a VW, so I might be a total noob but my first thought is that this coolant would just sit there and boil, or at very least be completely un-circulated. That doesn't seem right to me.

There are other places where the coolant passage is huge compared to the pinhole on the head gasket.

This all doesn't seem logical. Is this normal? Is this even the right head gasket? Is that the original head gasket?

edit: red are where holes should be and green are where pinholes aren't big enough.

edit 2: people say the images don't work https://imgur.com/a/NAyyGyZ

 

[landcrabmechanic]

Sounds to me that someone may have put the headgasket on upside down.



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[landcrabmechanic]

Or the wrong gasket. The pictures did not come through.

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[Dake]

Not sure why but one image attached and the others did not. They work on PC

 

[landcrabmechanic]

Now they are coming through

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[landcrabmechanic]

Nope, did not work on phone.

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[Dake]

Weird, here's a direct link https://imgur.com/a/NAyyGyZ

 

[landcrabmechanic]

How long was it run with straight water in the cooling system? I am of the understanding that the smaller holes in the gasket are to keep some heat in the engine. I could be wrong though. May be a fault in the manufacture of the gasket. If it a factory vw gasket, I would say the engineers must have a reason for it.

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[Dake]

To my knowledge it never ran on straight water. That last photo is the Parts Place Inc gasket and it too has some passages completely blocked off.

 

[briano1234]

I look at it as possibly that a radiator stop leak was used at one time or another which caused sludge to build up.
I too have had issues with head gaskets that seem to obstruct some of the passages. A good flush and back flush of the entire cooling system after you get it repaired is warranted. I have seen this on not only VW engines that I have worked on Diesel and Gassers but as well in the parts yards where folks removed the heads off of engines.

Using the proper coolant and Flushing and backflushing the cooling system every 2-3 years sames as bleeding the brake system insures that you are at the maximum coolant flow, and that the rust that may be occuring in the block is washed away... I used a Prestone product on my Diesel a few times over 20 years of driving it usually before a WATER Pump change or t-stat change, as it not only clears sludge out of the engine but the back flush also cleans out the radiator and heater cores.

If you have a partially blocked heater, a good flush with CLR on the heater matrix only and a back flush will usually increase the heat....

 

[Dake]

Makes sense about the Stop Leak. Making a mental note about flushing the system on a regular basis as well. Still would love to know the reasoning behind blocking off certain coolant passages, that coolant has no way to escape!

I have half a mind to drill out the next head gasket - never had an issue with this car running too COLD, only too HOT.