Peugeot 405 TD Headgasket.

alanshep · Unread post by **alanshep** » 01 Feb 2010, 08:15

Hello.

Following on from an earlier thread about the coolant system pressurising, yesterday I started the process of removing the cylinder head.

I've got as far as removing the inlet manifold (with hands to prove it).

I can now see the exhaust manifold. It was my intention to follow the Haynes manual and try to remove the exhaust manifold studs and leave the manifold and turbo in place. This will leave the weight of the manifold and turbo on the exhaust - I've read on the forum that I will need to support the exhaust accordingly.

My main concern at the moment is that I might strain the turbo oil pipes. I can see the oil feed pipe in to the top of the turbo. Do these pipes allow for any movement between the turbo and the rest of the engine once the exhaust manifold is free? Or should I be disconnecting these pipes whilst work is in progress?

Thanks

Alan

spider · Unread post by **spider** » 01 Feb 2010, 10:48

I've only done one on a 1.8TD 205.

I left the exhaust manifold and turbo in place, I just whipped the inlet manifold off and took the turbo oil feed pipe off completely and disconnected the rubber "drain" pipe where it enters the back of the block. You do need to take the oil feed pipe off.

I think attempting to take the exhaust manifold off in situ is just possibly causing yourself more work if you can leave it in place to be honest. If you can leave it in place, then leave it, you can always take it off the head once the head is off if required. It does make it a bit more awkward to move though.

With the top engine mount out of the way (you have this off anyway to do the timing belt) you can push / pull the engine forward enough to get it all out I think.

I would speculate you can do something similar on a 405 too.

Regarding the exhaust, if you undo the bolts where the downpipe fits you can either tie it up with a bit of wire or possibly it will sit on the subframe safely anyway.

Note: Remember this post is not 405 specific, sorry, but I hope it will throw a couple of ideas your way for the moment.

, I did not have any real problems doing the whole job at the side of the road (

)

EDIT... , Use two or one old head bolts (cut the head off them and make a slot in) to use as a dowel to help with refitting as its heavy and easy to put it back wrong due to only having one dowel.

evilally · Unread post by **evilally** » 02 Feb 2010, 19:04

I have done exactly this task recently

http://www.frenchcarforum.co.uk/forum/v ... hp?t=28392

Best to undo the lower and top engine mount. Then you can move the whole engine forward and get much better access down the back. You will need to undo the exhaust from the manifold to move the engine forward.

You need to remove the exhaust manifold as it shares the same gasket as the inlet manifold which needs to be replaced. I left the turbo attached to the manifold but undid the oil feed pipe at both ends to avoid stressing it.

alanshep · Unread post by **alanshep** » 04 Feb 2010, 11:17

Just an update.

Yesterday morning I managed to get all of the exhaust studs out. In order to do this I had to undo a small 'banjo' union on the left hand side of the turbo (this was fouling the spacer on the exhaust stud). I'm not sure what this is - it's not mentioned in the Haynes manual.

I also undid the oil feed to the turbo. It became apparent as I was doing this that the union nut had seized and I was unscrewing a boss (seated on a copper ring direct form the turbo). I'm not sure what this will have done to the pipe mating face - will need to investigate further.

At the moment the exhaust manifold and turbo are still connected to the exhaust (which is supported by a couple of bricks) and seems quite sturdy. As far as I can tell the only remaining connection back to the engine is the oil return pipe which has a flexible section in it.

Alan

Unread post by **CitroJim** » 05 Feb 2010, 13:59

alanshep wrote: I also undid the oil feed to the turbo. It became apparent as I was doing this that the union nut had seized and I was unscrewing a boss (seated on a copper ring direct form the turbo). I'm not sure what this will have done to the pipe mating face - will need to investigate further.

Yes, this can happen. If the pipe flare was spinning around than it may have slightly damaged it's seating. Once on the bench and counterholding the union, it should all come apart OK. You can then check for scoring and/or distortion on the pipe flare and seat.

be aware that some have a conical plastic oil filter in the turbo end of the pipe. Replace this air at least check it is clean and in good condition. It is designed to keep debris away from the turbo bearings. There's another filter like this in the head itself, lying at an angle of 45 degrees and feeding the camshaft bearings. It's easy to miss but a new one should be in your gasket set.

If necessary, and for peace of mind, renew the pipe and union if necessary but beware there are two types, one for the Garrett and one for the KKK turbo. They are not interchangeable! How do I know

alanshep · Unread post by **alanshep** » 26 Feb 2010, 12:02

Another update.

Got the head off earlier this week - not the most enjoyable of jobs so far I have to say.

Anyway, the existing gasket has 3+2 notches on it. Is this the thickest gasket available and if so does it mean that the head may have been skimmed previously?

I am going to take the head to an engine builders near to me for skimming. Presumably they will be able to tell if the head has previously been skimmed and if so, whether it can tolerate another skim?

Thanks

Alan

evilally · Unread post by **evilally** » 03 Mar 2010, 20:23

There is a 5 notch "repair" gasket available, you should be fine.

alanshep · Unread post by **alanshep** » 19 Mar 2010, 17:59

Hello.

Further to the above, today I started to clean up the engine block ready to refit the cylinder head. However, I've come across a bit of a problem.

At the bottom left hand corner of the block (near the oil feed) the cylinder head is quite corroded around one of the waterways. The corrosion extends onto the region where the cylinder is sealed by the ring in the gasket.

The head came off because the coolant system was pressurising. I've attached pictures showing the corrosion on the block and the original gasket at the corresponding location. I'm pretty sure this is where the leak was.

I don't think I feel very confident about this going back together and sealing. I'm interested to know what other people think.

Regards

Alan

tonupteabag · Unread post by **tonupteabag** » 23 Mar 2010, 14:18

spider · Unread post by **spider** » 23 Mar 2010, 14:22

Those pics show the block though, not the head...

tonupteabag · Unread post by **tonupteabag** » 23 Mar 2010, 14:24

i suppose you could try chemical metal not sure if it will hold though