Thread: Head gasket repair dodge

Keep us informed as to how this bidge holds up while you still have the D2.
I'm currently trying to sort my D2 V8, which may or may not have a head gasket leak too, so I'm curious as to how well your work holds up in the coming months.

Originally Posted by lyonsy

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also top radiator hose screw part stuffed up but found m10 bolts screw into the rubber hole so gave a heap of permatex ultrablack and a hose clamp over the top and no leaks even when system was at max pressure that i could hardly squeeze the pipe so anther dodge if ya get stuck somewhere.

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Same happened to brother's TD5 a while back when the bleed screw retired hurt with barely any effort!
Problem was it was late night, no shops open to buy stuff so we had to make do with whatever brother had in his shed(which is very little).
Tried a bolt, some rubber o-rings and clamp too, but it didn't hold.
But what did hold really well too! .. was a plastic wallmate, cut down so it didn't impede water flow too much, from memory down to about two of the threads remaining. The screwed in a wide headed tek screw(also cut down from 10mm, mainly to remove the self drilling end).
This bodge held up perfectly with no other assistance or rubber or sealant for months too .. and still worked perfectly as a bleed point too with the only caveat that the wallmate had to be clamped a little so that undoing the tek screw wouldn't remove it.

I would think that Many of us here would have had to "Bodgie" something up out in the scrub so that we can keep going But doing a "Bodgie" job as a long term fix is rarely a great idea and it usually leads to damage to other componentry and ends up being a more expensive exercise than fixing the job correctly in the first place.
Doing a "Bodgie" job simply to hide a problem on a vehicle prior to a sale is just so wrong on many different levels.

a few people asked for updates.
so still have it, its done about 2000km since and has been fine no overheating, does loose a bit of water but that's mainly from the header tank not being sealed so it cant pressurizer the system to reduce chances of blowing again.
so judging by that it has lost tension between the head block, half thinking of just throwing a gasket at it and turn it off roader only and get something else for family duties

"was talking to anther mechanic mate and we both agreed that the reason why it failed after only a 100'000 km since last done is when they skimmed the head the their was not enough surface hardening left so over time with all the heat cycles the head gasket has been able to move and chafe a little bit and over time has worn into the head due to loosing hardness and then the head has lost a little bit of pressure on it which has then allowed cylinder pressure to bypass into the cooling passage some where."

I doubt all of the above, it either wasnt hardness tested when the head was off and it was soft, the job wasnt done correctly to begin with or the head gasket simply failed.

"so if you get a head reco ether get it re hardened or use a heap of hylomar on it to try and stick gasket to the head much better"

I also wonder how the average workshop could possibly "re-harden" a head and you could use a whole tube of whatever and it wont make any difference if the head is soft.

Originally Posted by DazzaTD5

"was talking to anther mechanic mate and we both agreed that the reason why it failed after only a 100'000 km since last done is when they skimmed the head the their was not enough surface hardening left so over time with all the heat cycles the head gasket has been able to move and chafe a little bit and over time has worn into the head due to loosing hardness and then the head has lost a little bit of pressure on it which has then allowed cylinder pressure to bypass into the cooling passage some where."

I doubt all of the above, it either wasnt hardness tested when the head was off and it was soft, the job wasnt done correctly to begin with or the head gasket simply failed.

"so if you get a head reco ether get it re hardened or use a heap of hylomar on it to try and stick gasket to the head much better"

I also wonder how the average workshop could possibly "re-harden" a head and you could use a whole tube of whatever and it wont make any difference if the head is soft.

TD5 heads are only surface hardened when they are made so its only about 20 thou thick of hardness then its just what ever alloy they have used, this is why if you take more then 10 thou off the head they have a bad habit of being/going soft not like an old falcon head where you could take 60 thou off and still be right.
yes the workshop that did it i wouldn't really trust to of done it properly since when i brought it i took it back the next day as it filled the sump full of diesel and tried doing a runner as an injector tube was cracked, so they pulled the head they had it welded up, if i knew now what i know i would of got my money back but figured at the time well i shouldn't have any issues with the engine till up around the 500k mark, hell they may of even reused the head bolts and that could also be an issue

No a workshop can not re harden a head but maybe 1 in a 1000 mechanic workshops actually have the gear to reco a head
So when they send it off to a machine shop you get them to re harden it if they have the gear if they don't send it somewhere else,
hylomar will at least stick the head surface to the top layer gasket so so will hopefully slowdown chafing on the gasket to head surface it wont fix it but it should make it last a bit longer then otherwise

Originally Posted by lyonsy

TD5 heads are only surface hardened when they are made so its only about 20 thou thick of hardness then its just what ever alloy they have used, this is why if you take more then 10 thou off the head they have a bad habit of being/going soft not like an old falcon head where you could take 60 thou off and still be right.
yes the workshop that did it i wouldn't really trust to of done it properly since when i brought it i took it back the next day as it filled the sump full of diesel and tried doing a runner as an injector tube was cracked, so they pulled the head they had it welded up, if i knew now what i know i would of got my money back but figured at the time well i shouldn't have any issues with the engine till up around the 500k mark, hell they may of even reused the head bolts and that could also be an issue

No a workshop can not re harden a head but maybe 1 in a 1000 mechanic workshops actually have the gear to reco a head
So when they send it off to a machine shop you get them to re harden it if they have the gear if they don't send it somewhere else,
hylomar will at least stick the head surface to the top layer gasket so so will hopefully slowdown chafing on the gasket to head surface it wont fix it but it should make it last a bit longer then otherwise

incorrect......
*Not just a TD5 alloy head, any alloy head, the same case hardening is used.
*Any alloy head on a diesel with a hardness of 65 brinell or less will be pretty well useless.
*You can not re-harden a alloy cylinder head. (as far as general automotive repairs go).
*With the exception, if you had some irreplaceable head you can go through an expensive process of re-hardening which off the top of my head involves temps close to metal molten point etc etc.
*Comparing a alloy head on a diesel with a grandpa petrol tractor engine such as the Ford straight six is meaningless.
*Again no amount of gasket glue whatever is going to stop a soft cylinder head on a diesel from moving/flexing.

*Not just a TD5 alloy head, any alloy head, the same case hardening is used. Down further ill explain the 2 different hardening preocess's
*Any alloy head on a diesel with a hardness of 65 brinell or less will be pretty well useless. Yep that's close enough
*You can not re-harden a alloy cylinder head. (as far as general automotive repairs go). Again i said this with the fact that very few general workshops can do any specialist work they are all just assembler's of part's and they send the bits out to be repaired/rebuilt and i don't blame them even specializing in a brand their is far too many variations in vehicles to have all the machinery to rebuild and re manufacture every part of the vehicle, its why their is machine shops that specialize in machining, diesel fuel system shops, turbo shop's are normally with the diesel as well, transmission and drive line specialist's, why are their all these specialized fields because the cost to have all this for one workshop would be too great and even if they have it all unless you are doing it all the time you loose touch with it and become to slow to be cost effective.
*With the exception, if you had some irreplaceable head you can go through an expensive process of re-hardening which off the top of my head involves temps close to metal molten point etc etc. Their is 2 process's you can use for hardening a head you can heat treat the entire casting and use a harder alloy initialy so the entire head is treated the whole way through this is an older way of doing thing's mostly because its dearer to manufacture in this way but no amount of machining changes hardness only welding and heat cycles and if they used good hard alloy initially not alloy can's and slag heat cycles wont affect it,
or you can do what Landrover did and just face (case hardening) harden the surface's advantage its cheaper to do but it will only be around 20 thou (.5mm) thick of hardness so if you have to surface it at most you can take 10 thou and only then when it got a good face hard done.
It may in fact be only 15 thou or less thick meaning any machine work done will stuff the head but their is a possibility it will pass a Rockwell hardness test initially as their may be 5 thou of hardened material left but throw a few thousand heat cycles and the chaffing that occurs on the gasket from the head gasket and block expanding and contracting at different rate's and you get no or very little hardened surface left, but the advantage of this is anywhere that does case hardening should be able to re harden your head.
*Comparing a alloy head on a diesel with a grandpa petrol tractor engine such as the Ford straight six is meaningless. considering barra's are newer then a td5 i cant see how their an old tractor engine hell if the old 3.9 is at the same tech level and that was from the 80's,
But maybe Landrover should of looked to tractor and truck engines with their unit injectors a bit more and put an upper and lower o ring on to seal the fuel rail
*Again no amount of gasket glue whatever is going to stop a soft cylinder head on a diesel from moving/flexing. Never said it will fix it and solve all the issues, just that it will slow it down as it will reduce the head and gasket from moving on each other encouraging the gasket to do more of movement with a multi-layer gasket, it may last 20'000km or 100'000km it will just be luck of the draw,
Hell if you got really pedantic on it and re tensioned the head every 20'000km even with a soft head if you kept it cool it prob would never blow the gasket as it would be less likely to have lost enough tension on it between retension

Originally Posted by DazzaTD5

incorrect......
*Not just a TD5 alloy head, any alloy head, the same case hardening is used.
*Any alloy head on a diesel with a hardness of 65 brinell or less will be pretty well useless.
*You can not re-harden a alloy cylinder head. (as far as general automotive repairs go).
*With the exception, if you had some irreplaceable head you can go through an expensive process of re-hardening which off the top of my head involves temps close to metal molten point etc etc.
*Comparing a alloy head on a diesel with a grandpa petrol tractor engine such as the Ford straight six is meaningless.
*Again no amount of gasket glue whatever is going to stop a soft cylinder head on a diesel from moving/flexing.

As per my previous post and to add....

*Ford straight six design is what from the 1960's, and they put a alloy head on it, in what the mid 80's???? hardly a new design.
*Meaningless from the point of comparing a low compression petrol engine to that of the average diesel.
*If you mean the 3.9 Isuzu engine, then yes thats a old tractor engine too, with a cast iron head.
*The glueing a soft cylinder head on the average petrol may work for times you mention.
*A diesel wont tolerate running correctly with a soft cylinder head.