AX 14D Head Gasket

KAD · Post by **KAD** » 03 Nov 2003, 02:52

Just about to do a head gasket on a 1992 1.4 AX diesel. I've heard it is a weak spot (not found on the 1.5?). Are there any pitfalls or ways of improving it etc, so that it wont happen again??
(got a Xantia TD as well!)

AndersDK · Post by **AndersDK** » 03 Nov 2003, 04:24

Common pitfalls are :
Reluctance to spend the cost on a head skimming.
Re-using the old top bolts.
Not cleaning topbolt threads in the block.
Do NOT use ANY head gasket sealants !
Use the correct grade (thickness) of headgasket according to head skimmed.
Lightly oil the new top bolts on reassembly.
Follow torqueing instructions on the head gasket package or the top bolts package - they differ according to make/materials.

davek-uk · Post by **davek-uk** » 03 Nov 2003, 15:29

The 1.4D is renowned for throwing head gaskets presumable because it is an all aluminium engine; my AX goes through one every 50k miles regularly (it may be better if I had the head skimmed though - but it wasn't noticeably warped last time).
If you have to skim the head (recommended) then check the block (it may also need attention) and sleeve heights also. Do it poorly and you’ll be plagued by overheating in 20k where a small gap has reopened – been there and done it. But the engine is generally good and mine at 180k-odd still looks newish inside.
A pretty simple job with the only slightly awkward bit of releasing the top engine mount to be able to withdraw the exhaust manifold from it's studs - spend some time releasing the exhaust downpipe so that it can be swung aside.
General warnings as above, use a (new type) metal gasket, new bolts (the old ones will have stretched and they will be dirty) and clean out the old bolt holes thoroughly - you have to do everything to keep the bolt hole threads as new as possible, they can strip very easily!

KAD · Post by **KAD** » 09 Nov 2003, 19:36

That's great information there, I'll bear all those items in mind when I do the head gasket!
What makes the 1.5 diesel have such a good reputation then? Is it that much different to the 1.4? The 1.4 is in the low tax band and is a nice all alloy unit, albeit prone to head gaskets.

CITMAN · Post by **CITMAN** » 10 Nov 2003, 00:42

1.4 diesel engine was basically a petrol engine design and couldnt take the increased compression hence banging head gaskets, and also it was an all alloy engine where as the 1.5d has a cast iron block and alloy head like the xud. And the 1.5d was designed as a diesel engine thats the difference.

AndersDK · Post by **AndersDK** » 10 Nov 2003, 01:33

It does not matter wheteher it's a diesel or petrol.
The problem will all-ALU engines is their sensitivity to cooling problems any kind.
My CX 22 with the all-ALU Douvrin/Renault engine trashed the HG because of a coolant hose blow up on a longer trip - it happens that fast !
Carefully inspect the old HG when engine is apart - telltales are blocked/restricted coolant flow holes - due to deposits & therefore reduced coolant flow.

CITMAN · Post by **CITMAN** » 10 Nov 2003, 14:37

Dont know where I read it must have been years ago. I read that the PSA 1.4d used the petrol engine block from the TU 1360cc petrol engine as this is a wetlined engine see photo of peugeot 106 1.4d headless http://www.speedways.co.uk/gallery/peu- ... ll0012.htm. And as I have said before it was because the block was a petrol design and therefore weaker and it was only the pistons and head that where changed to increase the compression.
The engine in photo had suffered two head gasket failures in a few months, but this due to the head not being skimmed the first time.
Thats my opinon anyway?????????????????????????????????

CITMAN · Post by **CITMAN** » 10 Nov 2003, 14:52

Then again i might be wrong. Sorry if ive repeated myself but ive just got up.

arry_b · Post by **arry_b** » 10 Nov 2003, 15:26

Isn't the 1.5 in the lower tax band as well, the higher tax rate starts at 1549cc.