Head gasket change difficult??

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R

RJUU

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How do all turns out my 300tdi needs a new head gasket, coolant header bubbling then overflowing when driving.
Question is how hard is it? I’m quite keen to learn new things about cars. I’ve changed the gearbox and clutch myself a done all the usual servicing gubbins including valve clearance. Does it sound like I could do a head gasket change or not?

Cheers guys
 
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If you can do a clutch you should be bale to do the head gasket. The degree of difficulty and the tools required will depend on which engine you have.
 
If you have done a clutch, a 300-tdi gasket will be easy-peasy. Just get yourself a decent torque wrench and angle gauge and you're good to go. Set aside a full morning and go for it. If I were you, while I am at it, I would take the head for a light skim and pressure test, lap the valves and take the injectors for servicing. It will mean that the car will be out of service for a few days but the top end will be as good as new.
 
Just don't forget to empty ALL the coolant, including the coolant in the block. Otherwise you'll end up having to drop the sump to clean it too (not a bad idea once you're at it either).
 
reiny said:
Just don't forget to empty ALL the coolant, including the coolant in the block. Otherwise you'll end up having to drop the sump to clean it too (not a bad idea once you're at it either).
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Hicap phill said:
Easy job then :)
Steady 1/2 day to strip
Same for the rebuild
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Cheers guys your advice is much appreciated, is an angle gauge nesecarry as I’ve read each flat side to a bolt is 60degreese should this suffice?
 
Well, you can use the flat side to a bolt system but 10 of the bolts require a further 20 degree turn after 2 60 degree turns and an angle gauge is cheap as chips so why not get one to put your mind at rest?
 
reiny said:
Well, you can use the flat side to a bolt system but 10 of the bolts require a further 20 degree turn after 2 60 degree turns and an angle gauge is cheap as chips so why not get one to put your mind at rest?
Click to expand...
Ahhh never knew they were cheap cheers
 
reiny said:
Well, you can use the flat side to a bolt system but 10 of the bolts require a further 20 degree turn after 2 60 degree turns and an angle gauge is cheap as chips so why not get one to put your mind at rest?
Click to expand...
When it comes to filling coolant again is there a certain procedure to do so because I’m emptying the block?
 
not particularly although 300tdis are usually a PITA. Just open up the filler plugs on the fad and thermostat housing (replace them with brass plugs if they are still plastic jobbies), fill the system, wait until the radiator plug overflows and close it, fill some more, wait until the thermostat housing plug overflows, close it, bob's your uncle. What I usually do is even easier. I just remove the little bypass hose from the thermostat housing, fill the system until i get a steady dribble from the thermostat housing, refit the hose.
 
reiny said:
not particularly although 300tdis are usually a PITA. Just open up the filler plugs on the fad and thermostat housing (replace them with brass plugs if they are still plastic jobbies), fill the system, wait until the radiator plug overflows and close it, fill some more, wait until the thermostat housing plug overflows, close it, bob's your uncle. What I usually do is even easier. I just remove the little bypass hose from the thermostat housing, fill the system until i get a steady dribble from the thermostat housing, refit the hose.
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Cheers dude sounds like fun for me this weekend :)
 
reiny said:
Well, you can use the flat side to a bolt system but 10 of the bolts require a further 20 degree turn after 2 60 degree turns and an angle gauge is cheap as chips so why not get one to put your mind at rest?
Click to expand...
you can i do ,the angle gauge is bit of a pain, and the final 20 is 1/3 of a flat a decent marker pen helps to mark the bolts to show theyve been done at each stage and to see that your pulling exactly one flat by dotting the head and bolt flange edge
 
Hicap phill said:
Easy job then :)
Steady 1/2 day to strip
Same for the rebuild
Click to expand...

Half day? You'll have the head off a 300tdi in about 60 minutes! My record is 40 minutes.

Another hour to clean it all up and check things properly, if you are content it is just a blown gasket and there are clear signs of failure and want to simply refit the head with a new gasket then fine - maybe 2 to 3hrs to put it back together, torque it all properly, refill coolant etc.

I would almost certainly do a bit more than just the HG on it unless I'd done work to it previously or it was clearly good and passed the kero test etc. It would be wise to consider checking valves, lap them in - check valve guides (particularly exhaust) consider a pressure test in case the head is cracked which then caused the HG to go.

This job is not "difficult" but that assumes you have mechanical skills and the right tools - so yes it is difficult if you're not mechanically minded, or a walk in the park if your a time served motor engineer!

The first time I ever did a HG I was a teen, after a few weeks it leaked, I was redoing it again a month later! I learnt so much from making some mistakes that I will never forget these things - I didn't even really bodge or bash anything, I did it well, but I did a couple of daft little things than can be easily forgiven and it just didn't work, my mechanical mentor put it down to the learning process. Ever since then I have always had a thou skim put on a head just so I know it is dead flat and perfectly clean, I always use good gaskets, often new bolts etc.
 
discomania said:
Half day? You'll have the head off a 300tdi in about 60 minutes! My record is 40 minutes.

Another hour to clean it all up and check things properly, if you are content it is just a blown gasket and there are clear signs of failure and want to simply refit the head with a new gasket then fine - maybe 2 to 3hrs to put it back together, torque it all properly, refill coolant etc.

I would almost certainly do a bit more than just the HG on it unless I'd done work to it previously or it was clearly good and passed the kero test etc. It would be wise to consider checking valves, lap them in - check valve guides (particularly exhaust) consider a pressure test in case the head is cracked which then caused the HG to go.

This job is not "difficult" but that assumes you have mechanical skills and the right tools - so yes it is difficult if you're not mechanically minded, or a walk in the park if your a time served motor engineer!

The first time I ever did a HG I was a teen, after a few weeks it leaked, I was redoing it again a month later! I learnt so much from making some mistakes that I will never forget these things - I didn't even really bodge or bash anything, I did it well, but I did a couple of daft little things than can be easily forgiven and it just didn't work, my mechanical mentor put it down to the learning process. Ever since then I have always had a thou skim put on a head just so I know it is dead flat and perfectly clean, I always use good gaskets, often new bolts etc.
Click to expand...
Thanks for the advise buddy, so if I were to get the head skimmed should I just ask for a thou?? What is a thou?

Thanks
 
jamesmartin said:
you can i do ,the angle gauge is bit of a pain, and the final 20 is 1/3 of a flat a decent marker pen helps to mark the bolts to show theyve been done at each stage and to see that your pulling exactly one flat by dotting the head and bolt flange edge
Click to expand...
Hi James, thanks for the reply. obviously it seems to me that the headgasket has gone because the of the continuous bubbles comping out of the header tank then over flowing when driving. Is there anything I should check first to be sure it’s the headgasket? Is there anything else that could cause this to happen? When I pulled over the first time when it was starting to over heat I turned the tank cap and it would pour out but the second time I wouldn’t pour out it would almost make a gargling sound???

Thanks for the advice
 
RJUU said:
Hi James, thanks for the reply. obviously it seems to me that the headgasket has gone because the of the continuous bubbles comping out of the header tank then over flowing when driving. Is there anything I should check first to be sure it’s the headgasket? Is there anything else that could cause this to happen? When I pulled over the first time when it was starting to over heat I turned the tank cap and it would pour out but the second time I wouldn’t pour out it would almost make a gargling sound???

Thanks for the advice
Click to expand...
in most cases as is likely with yours the gasket isnt blown it leaking gasses over the fire ring to coolant way you can tell by black staining, could be few things like cracked block, blocked rad so not cooling you can test by feeling the rad core when engines hot it should be hot allover if not it wants replacing,thermostat not opening etc but if head gasket has been on awhile its most likely and i would change it anyway,still check rad etc as it might be a symptom of getting too hot or could just be it due to age and heat cycles
 
RJUU said:
Thanks for the advise buddy, so if I were to get the head skimmed should I just ask for a thou?? What is a thou?

Thanks
Click to expand...

1 thou or "a thou" is 1 thousands of an inch or about 25micrometers - a hair is about 0.06mm or 60micrometers so it is very very small. You may even get more taken off the head if it needs it 10 thou which is about 0.25mm.

The reason for the tiniest of skims is it will leave you with a very very clean head, the machinist will pick up on any warps too and can advise on repair feasibility. It should cost you £20 and will be well worth the money because cleaning an alloy head with the care it requires can be a PITA and I am a great believer in paying a little here and there to make things easier in life.

Don't take any more off than you need is my motto - too much and you need to change gasket thickness and things as the head looses material the valves get closer to pistons!
 
... And don't forget the correct tightening sequence of the head bolts!
Being an Old Gimmer, I remove the head bolts in reverse order to refitting them, and with my N/A, I leave the inlet and exhaust manifold attached as it makes the job a bit easier when there's something solid to grab hold of.
 
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