Xantia 1.9TD - Oil in coolant

[Old-Guy]

Changed the oil this morning, then checked LHM and coolant levels. Aargh! Black oil and mayonnaise in header tank filler neck/level indicator.

It's not serious yet as the overflow pipe was nice and clean - no trace of oil. I put the overflow pipe into a small drinks bottle, kept revving the engine and re-filling the expansion tank to the top until the fans cut in. I flushed out about 200ml of nice clean coolant, with just a few drops of dirty engine oil floating in it.

No signs of coolant in the oil - but then I wouldn't expect there to be (yet) as the oil is under a very much higher pressure than the coolant.

No bubbles in the coolant fortunately.

We're scheduled to make a long-overdue, 300 mile round-trip to see the grand-children in 5 days time and I'd like to postpone any major work until we come back as I don't have the time to do anything major.

O.K. so it's either the head gasket or the oil cooler, and given that the car has only done 99,000 but is 14 years-old:

1. Is either likely to suddenly let go in the next few hundred miles?

2. Where does the oil gallery pass through the head-gasket and when the oil gallery seal fails on the XUD, is it 'normal' (as on many engines) for an external weep to show and if so where?

3. If it's the oil-cooler leaking (into the cooling circuit), are there usually any external signs?

4. How easy is it to remove the oil cooler? I was thinking of doing so to inspect it for signs of oil in the coolant side, clean it thoroughly, by-pass it , run the engine and see if any traces of oil appear in the (clean and dry) coolant side?

5. Any other ideas on identifying which is leaking?

All (sensible) thoughts and ideas would be most gratefully received.

Guy

[KP]

it sounds more like the cooler to me fella

[Peter.N.]

Hopefully its the oil cooler, you can bypass it by joining the two water pipes together but it will take some while to get all the oil out. I had an XM that did this, sadly it wasn't the gasket or the oil cooler, must have been a crack somewhere.

The oil won't do a lot of harm, just makes a mess. What I used to do was periodically take the filler cap off and fill it to overflowing with the hosepipe, the oil will rise to the top and run out. I did some thousands of miles with mine and sold it like it, with the knowledge of the new owner

Peter

[Old-Guy]

Thanks for the reassurance, Peter.
Hopefully, it is either the head gasket or the cooler rather than a cracked head or block - as it's summer, I'm rather reluctant to take the oil cooler out of circuit permanently just because of a slight weep. I'm going to have to bite the bullet and change the heater matrix before winter, which will be a good opportunity to give the coolant circuit a thorough clean.

The head gasket would be a real PITA, I remember what a struggle changing the timing belt was for all sorts of reasons.

[Peter.N.]

Try doing it on a 2.1 -

[Old-Guy]

I saw some of your posts on the subject while researching the problem Peter. Engine out to change a head-gasket!

I suppose the only excuse for such an idiotic design is that most engines never need any serious work during the life of the original vehicle?

However, if you think this is stupid; I discovered a few years ago that on many Ford models (Mondayos, Focii etc.) that to change the lower N/S suspension link when the inner bush fails (every 30,000 miles or so), you have to drop the entire front sub-frame by 2-3", while supporting the power unit in place - simply because the gearbox is in the way of withdrawing the retaining bolt upwards.

[Peter.N.]

There is very little thought goes into provision for servicing vehicles now, with a few exceptions, BMW being one, I'm sure most are built the way they are for cheapness, to be fair though, although the 2.1 engine is a pig to work on, they very rarely go wrong, a head gasket every 150k is not bad, and that's about all you are likely to have to do to it.

Peter

[myglaren]

I saw some of your posts on the subject while researching the problem Peter. Engine out to change a head-gasket!

I suppose the only excuse for such an idiotic design is that most engines never need any serious work during the life of the original vehicle?

You haven't had a Hillman Imp, have you!

Headgaskets changed as regularly as the oil - in fact as the oil is replaced with the gasket job, it isn't ever changed at any other time.

I used to have three engines. One in and running, one ready to go in and the one just removed to replace the blown gasket.

Engine swap took 2 hours. Mainly due to lots of practice.

Got tired of that after a couple of years and bought a GS

[Peter.N.]

I think the last CX I had runs a close second, it was a CX25DTR Turbo - one of those with a porous block, I had to change the gasket about every 15,000 miles, I even fitted a new head and had the block machined, made no difference.

I covered over 150,000 miles in this car, how many head gaskets is that? I loved the car so much I was prepared to do that, and of course as the engine faced forward you could change three gaskets in the time it would to change one on a 2.1.

Peter

[Old-Guy]

If I do have to replace the head gasket, I shall (hopefully) defy modern practice by carefully and progressively un-torquing the head (to avoid distorting it). Once the joint face is really clean, on checking the head face for 'truth', I'd hope and expect to find no need for a skim.

I can't in all honesty, claim to have replaced hundreds of head-gaskets, a couple of dozen (none in the last fifteen years) would probably be nearer the mark but I've never had to have a head skimmed. In 60s and 70s, having (even an alloy) head skimmed was regarded as a last deperate measure amid accusations of "Ah, you didn't take the head off carefully enough". Bear in mind that most engines were push-rod (heads much less deep than OHC) and straight-6s were quite common.

I cynically suspect that the modern habit of skimming heads is both a lazy way to get a clean joint face and a means of inflating the bill.

The last head I did, on a Golf Mk1, 'proves' my point - we discovered it had a history of over-heating and blown head gaskets. When I took the head off, the stretch bolts had obviously been re-used several times and there were traces of several previous gaskets stuck to the joint faces. Surprisingly, the head was still true. Re-doing the job properly fixed the problem permanently.

Which leads me on to a couple of tricks for all heads with stretch bolts:
1. Choose an old bolt from on which you can clearly see how far into the block it had been screwed - put it to one side for reference.

2.Take a bolt with sound threads and with a junior hacksaw, cut a slot about 5mm deep across the threaded end - not perfectly across the diameter but slightly off-set. Clean the burrs off the threads. Spin this carefully down the threads in the block to clean out the threads (that's why you need a reference bolt). It's better than a tap which will inevitably cut some metal.

3. Saw the heads off two more old bolts. Saw a deep (>10mm) screwdriver slot in the top ends. De-burr thoroughly. Screw them as guide pins into bolt holes from which they can be 'easily' removed with a screwdriver jammed in the slot once the head is in place. These guide pins will stop the head gasket moving and align the head as it is lowered so there's no risk of the head moving around on the gasket and damaging it. Put ALL the remaining bolts in finger-tight, before replacing the pins with the last two bolts. Torque down strictly by the book.

This may seem like a lot of extra work, but it will save time and frustration and the risk of a cock-up.

I'll keep you posted with 'progress' on the oil leak.

[Peter.N.]

I have had most of my heads skimmed but must admit that most only needed a few thou, but for £25.00 which was about the price I thought it was worth it in view of the work involved in doing the job. I even put a new rad in my XM, just as insurance

Your idea for clearing the threads sounds a good one. I always use new bolts.

Peter

[KP]

Cheers for the tipe regarding the head bolts.

Having owned a R5 turbo and R5 1.4 Auto headgaskets don't scare me too much, its just now having the time to do them where as younger years meant i would work till 1am to get the job done right

[RichardW]

The main oil feed to the head is at the cambelt end - they can let go here pretty dramatically and dump a lot of oil out of the joint (this was the end of my first Xantia). Usuall when the oil cooler lets go it puts lots of black oil in the water. When the gasket goes you get less oil, and it tends to be brown rather than black. There's an exception to every rule of course! The 1.9TD will warp its head at the first sniff of over heating, but if not overheated and untorqued carefully it should be flat enough to re-use. For a garage charging 40-50 £/hr a 10 minute skim is cheaper to the customer than an hour spent cleaning the face with a brillo pad!

[Old-Guy]

Many thanks for the practical info., Richard.

I reckon that an engine that's been over-heated to any real extent is a bad risk.

If the typical garage's approach to a blown head gasket is to whip off the head, have it skimmed, slap it back on, torque it down (carefully I hope) and reassemble whatever else, then sooner or later, the gasket will go again (at least in part because the block face wasn't properly cleaned) and the process has to be repeated.

So, does anyone know much can be skimmed off an XUD head before the valve-seat inserts have to be removed, replaced, re-ground etc etc.?

Or, typically, does a pre-chamber insert fall out and comprehensively wreck the engine first?

Just interested.

Guy

[falling-out-with-my-car]

I hope it doesnt have the same effect as changing a BX head gasket they never seem to be quite the same engine once they are done.

regards Nigel.