Having been down that road and still wearing the t-shirt I would strongly advise against any pre 2006 MkIV 3.0 dci. If you are convinced that this is the engine you want then search 3.0 dci on this forum first.
Pre 2006 models use the P9X engine which was designed by General Motors and built by Isuzu under their code 6DE3. The engine was originally designed for the Vauxhall / Opel Signum project but never made it in to them. It was used in the Vectra, it was also used by Saab as the 3.0 TiD as well of course as by Renault in the Vel satis, Espace and Grand Espace. Both Saab and GM dropped the engine after short production runs due to the high number of total failure warranty claims they were receiving. Isuzu ceased production of the engine caliming design faults and the license for it returned to GM. whilst Saab and GM stopped using it Renault continued fitting it into 2006.
There are several inherant design problems coupled with the fact that the relative rarity of the engine means that non Renault sources don't carry parts and orginal equipment parts are hugely expensive. The fact the the engine is transversely mounted means that the entire rear bank is inaccessible without dropping the engine out.
Major faults include dropped cylinder liners (replacement engine and
, circa £8k new, £3.5k recon), premature high pressure diesel pump failures (pump rebuild circa £3.5k), premature
valve failures (replacement circa £750), Injector failure (not happened in mine yet, but injectors rrp is £150 each x 6 plus labour), failed engine mounts, countless electronic issues which due to the multiplexed computer system can be almost impossible to trace, even with the full diagnostic equipment, most common is dashboard failure, automatic park brake failure, immobiliser problems, abs problems. They also suffer from problems with the induction system, split intercoolers are common as are blown pipes and split resonators.
If I haven't put you off, and I sincerely hope that I have then you MUST find one which has had the engine changed, and check with the garage who changed it that the replacement used the redesigned block with "top hat" liners, otherwise engine life expectancy is sub 50k miles. My Espace had a new engine and
under warranty at 48k miles but alas the problems don't end there.
Insist on seeing any potential purchase with a cold engine, try and view it first thing in the morning before the garage can start it and warm it up. Have someone start it from cold and look for any smoke from the exhaust as it starts. give it a good test run including a patch of motorway / dual carriageway. Accelerate hard and watch for smoke haze behind you. Cruise along for at least a mile at 50mph in 5th manual then try to acclerate without changing down. Check for smooth power delivery and again, smoke haze behind you. Smoke, or the engine hunting for power are indicative of injection or
problems. Ensure that gear change is smooth even under heavy load. then brake sharply immediately after the hard acceleration and make sure that the down shift is equally smooth. Any jerkiness in the down shift is also indicative of an injection fault.
Make sure that the engine
is changed at least every 10k miles regardless of service interval reccomendations and that the correct
standard is used, fully synthetic of course. Don't just go with the viscosity rating, renault specify a specific acea rating. the lump uses just short of 8 litres a time at around £15/litre. Fuel and air filters must be changed regularly too.
Fuel economy is shocking, short runs from cold (school run etc) can return single figures, prolonged town driving will not get much above 20mpg though a good run on the motorway will get you 40+.
As for price these cars are pigs, and dealers know that so haggle hard and be prepared to walk away. You'll get sweet f.a. for it as trade in IF you can even find a dealer that will take it so expect it to be a rest of life "into the ground" purchase.
And finally warranty. I considered a warranty direct cover on mine but decided against it. Check all the small print especially with regard to labour cost, they originally quoted me max of £45/hour which is useless on this car. There are so many things that only renault can do (be aware that many components like injectors, fuel pump etc are programmed to the car and that few if any non main dealers carry the equipment to do it) that you must have full main dealer labour cover. Also check that there is not a single item value limit, my first quote was limited to £2000 for any fault. Once the labour cost and claim limit was removed they quoted me £1900 for two years on a 70k 7 year old car.
Even then, the limit per fault was still the "commercial trade value" of the car, and so a major fault like blown engine or diesel pump would not have been covered because the commercial trade value of these things is so low, thanks to their reputation.
I'm no great fan of the Chrysler myself, though have no experience of them. I looked at the Espace vs the Chrysler (LPG) vs a Kia (2.9 Diesel) when I bought. The only thing I know for sure is that I could not have done any worse then buying the Espace.