I'm shortly about to lose my company car and I'm looking to buying a diesel because I expect to be doing 15-20k miles a year. Although I've driven a company diesel for some time, I don't know what sort of checks I should do when buying one. Are the simple under bonnet checks the same for buying a diesel as they are for buying a petrol? Is there anything in particular I should be looking out for?
(I'm thinking of getting Mondeo 2.0 TDCi, either 115 or 130)
Any thoughts or help would be gratefully received!
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Modern common rail diesels are very complex beasts which are superb when everything's working properly (which is most of the time in fairness), but can be eye wateringly expensive to put right if they go wrong. Never buy a modern diesel that doesn't run perfectly (unless it's beer money), and never take the sellers word that a rough running / misfiring / poor starting / poor performance / excessive smoking fault will be cheap to put right.
Many of the checks on the mechanical parts are the same as a petrol engine. Check all fluid levels are correct, and for signs of oil/coolant mixing (mayonnaise on dipstick and around the inside of the oil filler, and rainbow / cloudy effects in the coolant tank). Check for oil leaks from above and underneath the engine. Make sure the clutch and gearbox work as they should, and the clutch doesn't judder or slip. Clutch failure on a new diesel can involve replacing the dual mass flywheel, which is megabucks!
Make sure the engine runs at the right temperature. Diesel engines are slightly slower to warm up than petrols - this is normal, but they should reach and settle at a mid point on the gauge (ish). Fluctuations are a sign of a fault.
Start the engine from cold, and it should fire up quickly and instantly onto all four cylinders. If it churns over for a long time, or fires up on two or three cylinders, this indicates glowplug or injector problems. Excess smoke on start up can also be caused by the same thing, or valve stem seal failure.
The engine should feel smooth and responsive in use. The turbo should give a smooth surge of power. A gentle, high pitched whistle from the turbo is normal. Any whining or squealing is not.
Some light puffs of grey/black smoke under hard acceleration is normal. Blue smoke at any time indicates a fault, as does any visible exhaust smoke at idle. On the Ford engines, any illumination or flashing of the glowplug light with the engine running indicates a fault with the fuel system which could cost you £,000's to put right. If the seller says its something simple, don't believe them. Get them to have it fixed, or walk away. Don't get involved.
That's about all I can think of.
Cheers
DP
--
04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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Thanks DP - a stack of useful info!
Just one question: how can I tell if it's not firing on all 4 cylinders?
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Misfire= irregular sounding running, loss of power, hesitation...especially on acceleration at 1500- 2500rpm.
Other hints: A fulll dealer service history is useful. Try to look at old bills. On Fords, if you see "reprogramming injectors", run a mile.. imo. Ford have a poor dealer record in solving problems...
Ask owner /dealer if any engine problems.. preferably in front of witnesses.. and repeat the answer to make sure you get it right... then if anything does go wrong, misrepresentation.
Personally i would ONLY buy from a dealer who is reputable...
If there is no recent history and it has missed a few, walk away... too much to go wrong with dirty oil..
A lot of shiny new engine parts# in an otherwise dirty engine bay suggests prior owner may have had problems which were £1000s to fix so sold it whilst working!
# injectors/glow plugs and various control valves.. obvious when new as shiny!
madf
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What's your budget, could you stretch to a nearly new car with plenty of manufacturer's warranty left? Much the safest option.
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I agree with Nick, because its the `uncheckable` thats the worry. Such as, has it had a severe misfueling of petrol ( run until ground to a halt) and been taken straight in for PX as a result?
Heres the link again
www.simong.org/index.php?p=902
Best reason ever to PX a good looking newish common rail diesel?
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Not read that site before, Oilrag, staggering!
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Its got to be the tip of the tip of...the iceberg. I mean,how many misfuelings are going to appear on that blog, 1 in a thousand? worse than that?
Regards
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The problem with any second hand diesel IMHO is that if it develops problems with the fuel pump etc. the garage may well say it is due to misfuelling (after you purchased it from them, they will deny the problem was there when they sold it). This will not be covered by the manufacturers warranty. You will then have to prove that you did not fill it with the wrong fuel. Clearly, you can't do this. For this reason my next diesel will be new - if anyone knows a solution to this I would be grateful - I hate buying from new.
On the subject of checks, start it from cold - lift the bonnet and check it is cold - broken pre-heaters will show up through loads of cranking and a big cloud of smoke. If the engine is warm they will be harder to spot.
Big Norm
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You will then have to prove that you did not fill it with the wrong fuel. Clearly you can't do this.
You have your till receipts showing fuel and amount, write the mileage on the top of the receipt and keep in a folder.
Unless you're Alan Whicker's chauffeur you won't have too many receipts at the end of each week/month/year.
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When its been filled with petrol and ground to a halt, you get it drained, throw the petrol receipt away and use the new one on the diesel refill. Seamless, except for the few yards of mile or two it drove on the petrol........
Regards
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>auditing receipts
So to prove it, you get yourself a credit card that you use for nothing other than refuelling. So the CC bill will reconcile back to the receipts you have and will prove that there are no additional receipts (unless you have a penchant for vandalism!).
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can you justify the extra cost of buying a diesel car and the extra cost of buying diesel for 20k miles a year? Diesels cars seem to hold their value better, which makes petrol cars a better secondhand buy.
I doubt a car type diesel engine will last any long than a petrol one.
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Assuming you get to SEE the service history, chack if they've noted the BRAND & SPECIFICATION of the oil used, in the changes.
Some service centres, might not have used long drain/synthetic or correct oil.
Not sure how old you were going, you've not mentioned a VW, but important if you did consider Passat - I wouldn't, your Mondeo will be a fair choice, although don't discount Vectra & Mazda 6.
& if you were going back to REAL value, Pug 406 is well worth considering - if you can find a nice one - that's the hard bit!!
VB
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Thanks everyone for their advice - sorry for the slow reply as I've spent a frustrating few days without internet access.
In answer to a couple of questions:
My budget is £8000. The car cannot be older than 3 and a half years old. The reason for this is because my new job has offered money instead of a company car but with that comes certain age restrictions on the car I buy. It also needs to be big enough for two children which my current car isn't.
I'm steering away from the Mondeo a little bit (sorry but I've been spolit a little with a BMW 118d Sport as company car for the last 18 months so I've turned into a bit of badge snob!!!) so I was also thinking of the Saab 9-3 1.9TDi 120 - I've seen a '54 plate for £8k with 60k on the clock. Is this a good deal? Are Saab diesels any good in terms of reliability, cost of ownership, longevity??
As for the Passat, that's interesting you mention it because I've a friend with the new shape and doesn't have a good word to say about it or VW. The old shape still seems a little pricey too.
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