Disco 2 Heater, coolant, head gasket

raywin · Feb 25, 2018

Bantam1 said:
And all done!
Started up great, runs as it should, only difference is it isn't pressurising the coolant.
I've run it on a good run twice now and heater is fine, temperature is fine and coolant hoses are not pressurised.
So the moral of this story is as soon as you get a cooling system pressurisation issue get a new head gasket on it quick.
If you do you should change the plastic dowels for new steel ones but you can re-use the heads bolts and the turbo to manifold gasket too.
Oh yes I re-used the rocker cover gasket as well, just cleaned it up and when I put it back on I used some RTV as I use on my motorbikes to give a better seal.
A good few hours work (10 in my case) but for the cost of a head gasket, antifreeze and a bit of RTV, why wouldn't you?

Great news
Did you get a gasket kit with bolts and everything together? My cam shaft is goosed and I want to try and get it done this year. Mine is a 2001 defender with 120 k miles so I am looking at pulling the engine and doing the rings and bottom end shells at the same time. Hope to make a bit of a project of it later when the weather gets better.

Bantam1 · Feb 25, 2018

raywin said:
Great news
Did you get a gasket kit with bolts and everything together? My cam shaft is goosed and I want to try and get it done this year. Mine is a 2001 defender with 120 k miles so I am looking at pulling the engine and doing the rings and bottom end shells at the same time. Hope to make a bit of a project of it later when the weather gets better.

I only changed the HG and re-used the bolts because I don't see why you can't if they haven't been used beyond their elastic region.

Kev12 · Feb 25, 2018

Fingers crossed you are sorted, but if you have it off again I would say you need to look for another machine shop. The one I use locally only charges a tenner just to test and about thirty quid for a skim

Bantam1 · Feb 26, 2018

Kev12 said:
Fingers crossed you are sorted, but if you have it off again I would say you need to look for another machine shop. The one I use locally only charges a tenner just to test and about thirty quid for a skim

I kept the inlet and exhaust manifolds on and to test it I would have to strip it down for the machine shop. I'd probably have tested it myself if I was that concerned.
Thing is, if it isn't warped and there are no signs of stress cracking in the combustion face and it runs perfectly well, why would they suggest a test and skim in the first place?
The test is possibly worth a bit of effort if as a machine shop you know of specific issues unique to that particular motor type, such as valve seat base cracking or something unconnected with overheating. Otherwise if it runs well its only a revenue generator.

Kev12 · Feb 26, 2018

I was more suggesting that the machine shop should have given better advice than just wanting to skim right off the bat.
Maybe the TD5 is on their list of heads to pressure test as a matter of course, as cracking isn't unheard of

Bantam1 · Feb 27, 2018

I've now been running into work and back for a couple of days.
It drives great and coolant stays on level with no pressurisation and heater works perfectly whether driving or waiting at lights.
I think that's job done..........

Alpinejim · Feb 28, 2018

I hope your problem is fixed. Just be aware that it might come back over time.

I had similar issues and drove 2000 miles after an HG change only to find the problem returned as the HG bedded in and combustion gasses found a route in to the coolant again.

You should also to be sure to torque the bolts up correctly. Use assembly grease under the bolt caps and clean the threads in the block as good as possible to get the correct torque.

Screwing a bolt into a gummed up thread with hit the torque figure before the bolt is fully home, so to speak. Too late for you if you didn't do it.
I'll say nothing about re-using bolts as I don't know enough about the facts.

My problem was the block itself. It seemed flat when checking with a flat edge but actally needed a few passes on the mill to make it smooth again. If memory serves, they took 8 thou off to make it all shiny again.

Hellastony · Feb 28, 2018

Bantam1 said:
I only changed the HG and re-used the bolts because I don't see why you can't if they haven't been used beyond their elastic region.

Surely once they have been used, they are stretched to/beyond their "elastic region", which is why with these and other head bolts they recommend that they be changed regardless? It is not unheard of head bolts that have been re-used breaking after a while, but I do hope for your sake they don't...

Tony

Bantam1 · Feb 28, 2018

Hellastony said:
Surely once they have been used, they are stretched to/beyond their "elastic region", which is why with these and other head bolts they recommend that they be changed regardless? It is not unheard of head bolts that have been re-used breaking after a while, but I do hope for your sake they don't...

Tony

If they were taken beyond their elastic limit they would experience a degree of plastic extension, which would show at the narrowest point on the bolt (normally the threads).
I haven't done the maths but I would imagine it to be more of a concern for fatigue failure but the preloading of a bolt to resist the combustion force ensures it doesn't see that force, only a small percentage of it which is unlikely in itself to create a fatigue failure in the bolt anyway.
I wonder if it is recommended in case a bolt has been over tightened previously and extended, but again you would expect to see damage and would then not use it.
Its an interesting thought process though.

Bantam1 · Feb 28, 2018

Alpinejim said:
I hope your problem is fixed. Just be aware that it might come back over time.

I had similar issues and drove 2000 miles after an HG change only to find the problem returned as the HG bedded in and combustion gasses found a route in to the coolant again.

You should also to be sure to torque the bolts up correctly. Use assembly grease under the bolt caps and clean the threads in the block as good as possible to get the correct torque.

Screwing a bolt into a gummed up thread with hit the torque figure before the bolt is fully home, so to speak. Too late for you if you didn't do it.
I'll say nothing about re-using bolts as I don't know enough about the facts.

My problem was the block itself. It seemed flat when checking with a flat edge but actually needed a few passes on the mill to make it smooth again. If memory serves, they took 8 thou off to make it all shiny again.

It takes a lot to warp a block, its a hell of a section to bend when you think of it and more often than not its cast iron as well. I've never had or seen one warp but I have seen a head warp through overheating, especially ally ones.
The benefit of modern torquing techniques is that we don't use torque wrenches now we use a number of turns or angle of turn to achieve the torque setting. This cuts out all the issues that cause inaccurate torque, like threads, bolt head stiction, etc. as you said. The thread pitch provides the turn requirements, from a notionally clamped position, to put sufficient tension into the bolt, of known modulus, to provide the clamping force.
I'm hopeful the engine will be good and as someone said above they have got another 5 years and going strong.

jamesmartin · Feb 28, 2018

Hellastony said:
Surely once they have been used, they are stretched to/beyond their "elastic region", which is why with these and other head bolts they recommend that they be changed regardless? It is not unheard of head bolts that have been re-used breaking after a while, but I do hope for your sake they don't...

Tony

theres a measurement that if bolts go beyond you dont reuse,but generally bolts can be used several times

Disco 2 Heater, coolant, head gasket

raywin

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Bantam1

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Kev12

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Bantam1

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Kev12

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Bantam1

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Alpinejim

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Hellastony

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Bantam1

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Bantam1

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jamesmartin

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