C5 V6

[robert_e_smart]

Chaps,

Quick question:

I have found a series 1 C5 V6 for sale locally with autobox failure, the car was bought off a Citroen Dealer, which diagnosed the problem as the valve block.

The car has the 4HP20 box. I have a spare 4HP18 box from a XM, will the 4HP18 have suitable parts to repair the valve block on the 4HP20 box?

Regards

Robert

[CitroJim]

Hi Robert,

Sadly no. The 4HP18 is mechanical and the 4HP20 is auto-adaptive electronic and totally and utterly different inside.

However, having said that, the normal 4HP20 valve block problem is (as with the 4HP18 I believe) broken springs. These might do.

Rarely is this the only problem on a 4HP20. Normally they die from choked oil filters which can be a cause of or a symptom of something else; a clutch breaking up will clog the filter and initiate a vicious circle.

They are amenable to repair and if the car is cheap as a result, worth doing. Spares are readily available if not a tad expensive. Luckily the cabbie's favourite mini-bus (the Merc Vito) uses the same 'box and this ensures spares supply.

Have a look at my "Brief Encounter" blog that chronicles my first 4HP20 rebuild and then have a look at this site...

Between them, you'll see what you might be letting yourself in for

How exactly has the 'box failed in this C5. Has it lost all drive completely?

A 4HP20 is a lovely 'box when working and so is the engine too...

[robert_e_smart]

Hi Jim,

I have had a read of your work on the autobox from your website.

Its an excellent insight into how these things work.

But I have decided to pass on the C5, for numerous reasons, its a C5, too many other projects, and cash flow.

But thanks for your help.

Regards

Robert

[CitroJim]

That's a shame, could have been a good project

Did you see the mileage this C5 had clocked up Robert?

The 4HP20 rarely makes it past 150K before it needs and overhaul.

[robert_e_smart]

It was in the region of 110k, which surprised me that it lasted only a short time.