My wife & I each run Saxo deisels on our driving school. We normally change cars every two years when they've done about 80,000 miles. Because of the milage we take a fair hit in depreciation, but it will be worse this time with the drop in new car prices effecting the second hand market.
Negative equity re the finance means the cars will have to run to about 120,000 (very hard) miles before they can be replaced. Is it worth using oil an oil additive to preserve engine life? Are they just a bit of clever marketing, or do they really make a difference? I've always thought that if whatever is in them is any good, the oil producers would be putting the stuff in anyway.
By the way, adding Wynn's Deisel Clean to the fuel hasn't made any difference to my car's fuel economy or performance (present 53,000 miles).
Any thoughts?
Tom
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Tom
Although you say your cars get hard use, in fact they have the benefit of most high mileage cars - a relatively low proportion of cold starts, and many miles at proper operating temperature. I guess the hard used parts are clutch and transmission with all the about town work. Additives won't help the clutch, but you could consider using a fully synthetic oil in the gearbox/diff.
As for the engine - given that modern oils are 25% or so additives anyway, and the manufacturers spend millions on getting the right additive 'package', it sems perhaps unwise to add another dose of unknown additives to the mix. It strikes me your best bet is to use a good quality oil and change it at the recommended mileage intervals. 120k shouldn't be a problem. The instructor who taught my daughter clocks that up in about 18 months using petrol engined 1.2 Corsas and reckons to have no engine or gearbox problems during that time using standard 10k Vauxhall dealer services. But, he did say that the trade in value at that time isn't high!
Check www.geocities.com/chrislonghurst/ for some views on oils and additives.
Regards
john
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If you are seriously interested in additives I suggest www.vtr.org/maintain/oil-additives.html
simon
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Tom,
if you want to be put off oil additives for life go to.www.geocities.com/chrislonghurst/engineoil_bible.h...l
It appears every one ia complete scam whose makers are about to be sued in the states or discredited by everyone and his dog.
Alvin
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I've gone to the site you suggested, and yes, I have been put off for life! Thanks.
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Tom - regarding your question about Diesel Clean, my experience with the Nitrox equivalent is that it made no measurable improvement to economy with a 205 D-turbo, but it certainly can help with performance, and cleaning up the exhaust gas for the MoT. I have no difficulty getting smoke opacity below 1 unit (3 is permitted).
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Tom,
If you have caught any of the threads where I've mentioned our BX TD you'll know I'm amazed by its 215000+mls on original engine/gearbox/turbo, the head has never been off.
I put this down to regular maintenance/attention to oil, coolant, timing belt etc. Since 170,000mls we have been changing the oil/filter at 3,000 mile intervals, there is evidence the previous owner did the same.
I would expect your Saxo to breeze up to and beyond 120000mls with decent maintenance.
My personal view is that any extra expenditure is better spent on increasing the oil change frequency rather than confusing the chemical cocktail.
David
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David
You're right it may be an advantage to change oil more often. However, when a vehicle is doing 80k a year (as is the chap I know) even a 10k service comes up every 6 - 7 weeks, and a 3k oil change would be once a fortnight! frankly, it's just too often to consider. The saving grace is the fact the car has only about 300 cold starts in the 80K miles, and spends all day hot. The cars still sound OK at these high mileages, so servicing is limited to the makers recommendation.
regards
john
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A report buy the TUV and the major oil companies in Germany says that modern oils easlily last upto 50000km under harsh use without any real deteriation .It goes on to say that too frequent changing is bad for your pocket and bad for the world .You here of people saying that I change my oil more often and the motor is perfect (I am guilty of this phylosphy).
I remember a Golf bought in 92 did over 250000km in three years and it never had an oil change or filter change or service it was only topped and would you believe it never gave a minutes trouble and passed its first TUV (MOT) with no problems of course we changed pads and tyres but that is all
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Andrew Bairsto wrote:
>
> A report buy the TUV and the major oil companies in Germany
> says that modern oils easlily last upto 50000km under harsh
> use without any real deteriation .
With a wet clutch or dry clutch?
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Yet look at what the truck operators do, they change the oil at astronomical mileages, quite a lot have a top up tank so that some more oil is pumped into the sump at predetermined intervals to keep it topped up automatically. Mind you they do analyse the oil to determine when it really does need a change.
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Stuart
Yes, oil condition monitoring is exactly what operators of large diesels used in ships or for generating plant, not to mention industrial gas and steam turbines, use. You can't afford to just change the oil regularly on these 'just in case', nor risk breakdown due to oil failure.
Unfortunately it's not economic on your car engine. BMW etc get closer with service indicators which monitor engine use, but given the financial balance between an engine rebuild and changing the oil regularly, the only real option is the oil changes!
Regards
john
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John Slaughter is right that my 3000 mile oil changes are totally wrong for a high mileage car that is running/starting hot most of the day. I was talking about the broader issue comparing the change cost/frequency against additive use.
We cover about 12,000 miles in each vehicle and some of our journeys are less than 5 miles hence my decision to go for 3,000 miles oil/filter change.
On our soon to be re-built diesel Land Rover (that will cover just 6 miles a day) I will change the oil 6 monthly......so at just over 1000 mile intervals. I know these intervals are a little frequent but they will preserve the engines better than buying £2.99 oil at the boot sale for a top up and forgetting the changes completely.
We're talking good value preventitive maintenance here. You can prove anything with tests/statistics but I know of many engines ruined at 70,000mls by lack of oil changes and of many more that go on for ever when cared for.
David
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Thanks for all the advice, the general opinion of regular changes without additives seems the best solution.
Now, if anyone knows how to keep a much abused tuition car running to 120,000 without the transmission sounding like a bucket of nails in a spin dryer........
Tom
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What were the post war car sellers tricks? A banana in the diff and an egg in the radiator, or was it the other way round?
David
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Tom
Try changing the transmission oil occasionally (it won't be a regular service item) and use a synthetic oil in it.
If it gets noisy, I always thought the remedy was a can of STP or in extreme cases a couple of handfuls of sawdust.
David, yes, you have it the right way round.
Did I ever mention my mates Norton on which he siezed the pistons by doing a ton in the summer with virtually no oil in the engine - no, better not - someone reading this may have bought it........
Cheers
john
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You were right David re the bannana and the egg but, you overlooked the nylon stocking. Fed down the dipstick hole, one or two of them would wrap themselves around the white metalled big end bearings and, for a while, so it has been said, would really quieten a slack big end bearing.
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John,
Would that be the girlfriend's or..........well, you own?
David
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Go to work on an egg worked well in the 60s! The white of egg in the radiator every 2 days (it was side valve MM with no water pump) worked wonders and genuinely worked!
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