Having seen many people, including myself, trying to find info on the ever so common Head Gasket failures on Peugoet/Citroen XUD Deisels, I’ve decided to give a report on the repair I did to my Head Gasket failure on a 1993 Citroen ZX 1.9 Turbo Diesel. I repaired this on my drive and saved a possible £300+ on what a garage would charge. Not the easiest job to do, but when on a budget and needs must……say no more! I hope I can help a few others along the way.

Before discovering the gasket was blown, the radiator sprung a leak. I put it down to age and promptly replaced the radiator. A few weeks later the temperature gauge would sit low and then suddenly shoot up to around 100-110, before gradually falling back to midway and wavering around the middle. I then decided maybe a sticky thermostat might be at fault. So I replaced that, too. The symptoms remained the same. The car didn’t overheat but did continue to run warmer than usual. The oil and coolant looked clean, but the car did gradually use more and more water. Then one day it blew the bottom radiator hose off.

From cold, on tick over, with the radiator cap removed, there was no evidence of bubbles. Only when increasing revs did it become apparent that the head gasket was leaking as the water gradually became foamy. My guess is that that radiator failed not just because it was old, but with help from the failing head gasket, pressurising the system and followed by blowing a hose off and then choosing to leak out of the radiator cap after journey.

So here I am with a car that only has 110K on the clock, a few months MOT and a blown head gasket! At this moment in time I’m all about cheap motoring. Do I fix it or do I cut my losses and sc*** it……. Well as a hands on test engineer, I’m more than capable of repairing it, so I gave it a go. When asking my mechanic friend what he would charge if he repaired it, he told me £500 including the head skimmed and pressure tested. Not a cheap fix, and as I only paid £265 for the car, not really an option. I priced up the parts including a head skim and I’ll say it’ll cost you around £175 give or take a few quid, which included all filters, oil, complete head gasket set, genuine pug/citroen head gasket, Timing Belt and a head skim.

Citroen quote the job as being around 10hrs, start to finish. Now you have to bare in mind that this might be the case if you were an experienced mechanic who does this sort of thing day in day out, has I nice 4 post ramp and every tool you can imagine. I do this sort of repair once in a blue moon. It took me the best part of 2 weeks, putting a few hrs in here and there. I didn’t rush it, I was slow, careful and methodical. Working in aerospace, this is an essential and always a worthwhile approach.

Now if anyone has tried to do any maintenance on a Citroen or Peugeot, I’m sure you’ve used a whole array of swear words each time you did. French design their cars in a way that does facilitate easy maintenance. There is little room to work, as with most cars nowadays. So here’s a few a tip that will make life easier. Firstly, take the radiator out. Then disconnect the exhaust from the manifold. Stick a jack with a piece of wood on top and take the weight of the engine on the jack. The Haynes manual (which only give one way of doing things and not always the best!) will tell you to only remove the top engine mount, but I strongly suggest you remove the bottom engine mount behind the sump, too. What this allows you to do is rock the engine forward in to the engine bay (being careful not to pull the driveshaft about too much), making everything much more accessible and far fewer swear words!

Removing the timing belt and locking the pulleys is straight forward. When you have the engine locked in TDC on pistons 1 and 4, you can screw two M8 bolts through the cam shaft and diesel pump pulley. To lock the flywheel, use another 8mm bolt to lock the flywheel. But to access the hole to lock the flywheel in place, your best bet is to unbolt the starter motor from the bell housing. Only 3 bolts and it falls away. Behind where the starter motor sits, you’ll find the hole.

You can now safely strip the rest of the …almost everything!.... off the engine to get the head off. I carefully wrapped anything fuel line related, with cling film.

With the head off, I found the evidence with pistons 2 and 3 with a little rust in the tops of the bores where the head was leaking. After cleaning the head and running a straight edge across it, my head was as bent as £3 note. So off to an engineering shop to get it skimmed.

I had 15 thou or 0.38mm taken off. I was quite alarmed when first told, but on further research, I found this to not be uncommon. Sometimes they can require as much as 30 thou or 0.72mm.

So now it’s Gasket selection time. I found a few comments across the forums where people have been struggling on which gasket they should select. I was informed by the Citroen dealers that when the car came out of the factory, it could have had either 1,2 or 3 notch gasket. Coming from a machining background, I can appreciate that we’re not in an ideal world and so not all engines are manufactured identical. Mine had a 3 notch gasket. This is identified by a tang that sticks out the gasket. There are 2 rows of notches and the notches closest to the corner of the gasket, represent the gasket thickness. I discovered that if you have as much as 20 thou taken off through skimming, that would require a 1 notch increase. I’ve read that some people have said, just stick on the thickest gasket you can (being a 5 notch). Although it may work, it’s not right and being a Diesel, this gasket thickness must be important. I may be wrong and someone might correct me on that one. Anyway I selected a genuine Peugeot/Citroen 4 notch gasket.

I cleaned every gasket face as immaculate as I could and replaced every disturbed gasket on the engine. I see lots of people try and bodge old gaskets back on engine and out comes the gasket goo. There’s a reason why manufacturers don’t use it and that’s because providing the surface is clean (I mean really clean), flat and undamaged and you use a fresh gasket, it will seal.

With the car all back together. I pumped the primer pump about 30 times, I turned the key, waited for the glow plug relay to click off (not the light), full throttle and after about 15 turns, the car sprung in to life. A couple of misfires and then it sat there idling like it had never been apart. No a single leak anywhere and a job well done! Man, I was happy!

So hopefully another year of cheap motoring!

I once had a guy interested in another ZX Estate TD I was selling. He told me he had just sc***ped one of these with 540,000 miles on the clock! Say’s it all really! What an engine, just a shame they blow head gaskets!

Edited by Dorlingus on 30/04/2010 at 23:55