Doctor Diesel

Looking after a fine Patriot

As a regular subscriber to Diesel Car for over 14 years, I would be much appreciative of your advice. My 2007 Jeep Patriot, which is powered by a VW 2.0 TDI PD engine, has always used the recommended PD oil to specification VW 505.01, which is a 5W/40 fully synthetic grade. My local supplier has recently informed me that the A1 motor stores oil brand Technolube are no longer supplying a PD specific oil, and they now recommend a VW 504-507 specification 5/30 grade oil. The car has just over 100K miles on the clock, and has a full Jeep service record, using engine oil supplied by myself, and I am well aware of the special stresses imposed by the PD fuel injection system on the VW engine. Could you please advise me if it would be safe to use the VW 504-507 5W/30 grade oil without risk to the injectors, camshaft, etc., or would I be better continuing my search for an alternative oil supplier that can offer a fully synthetic 5W/40 oil to the original 505.01 specification? Can you possibly recommend to me an alternative oil supplier that does offer the 505.01 oil? Thanking you in anticipation, 

Robert Abraham

Hello Robert. 

Thanks for your e-mail message. As far as I am aware, VW 504.01 and 507.00 are not really suitable, as they do not have the qualities needed for PD engines. I doubt that the engine would suffer, or blow up, unless it was driven really hard, but there is no doubt that these oils are not strictly correct. You do need a VW 505.01 5W/40 oil. Others that I have seen quoted as being suitable are mostly 5W/30, and not 5W/40, for a start, which may not be critical, but 5W/40 must have been specified for a very good reason.

Suppliers of the correct oils are Millers Oils, who offer two possible products – see full details on their website: they are XF Longlife 5W/40, and a superior grade, with nano particles for extra protection – EE Longlife 5W/40. A company called Titan Oils offer Titan GTI 5W-40 XTL, which is specified for PD engines. If you search the web for VW 505.01, you will probably find plenty of sources, mostly available mail order only. So you can either try and find your nearest Millers or Titan stockist, as otherwise you may have to pay carriage costs. I hope this helps, but if you supply me with your postcode, I can try and find a nearby Millers stockist. 

Best regards, 

Doc Diesel

P.S. Well done for keeping the Patriot so long. Has it done a lot of miles?

Robert gave me his postcode, and I was able to advise him that Eastfield Discount Auto Spares in Peterborough were the nearest Millers Oils stockists that I could find for him. He told me that the Jeep’s mileage was a shade over 100K, and that he had only had to replace one battery, a turbocharger (a reconditioned unit supplied by Turbo Technics, at a great saving on the cost of a new one), and a few sets of Falken tyres. His car is run strictly on Shell Super diesel, giving a regular 45 to 50 mpg, and “still feels a very sound vehicle, due to excellent servicing by Westaway Motors, Northampton” – an excellent garage reference for any Diesel Car readers in the Northants area with a Ford, Jeep, Isuzu, SsangYong or Mitsubishi. Thanks Robert.

Doc Diesel

Effective Additives

Hi Doctor! 

It has been about six months since I last e-mailed you with reference to using diesel additives, asking for your advice, and I thought that it was time for me to give you an update. Since your recommendation of the product last February, I have been using Millers Diesel Power Ecomax in my Volkswagen Passat 2.0 TDI 138bhp manual saloon, with interesting results. As I told you before, my annual mileage is relatively low, and the car has only covered about 3,000 miles in the six months since I started using the additive. You may also recall that I told you I rarely make journeys of less than around ten miles, and that I occasionally tow a caravan.

I took your advice and used a double dose of the additive the first time I put some diesel in the tank, and since then have usually been buying 30 litres of diesel, as required, to which I have added 30ml of additive (That’s a 1000:1 ratio, for readers). For the first couple of weeks, when I stopped the engine after a good run, I noticed a certain aroma coming from the car that I can only describe as being similar to burning soot. I presume that this was caused by the additive doing its job, by removing deposits from the turbocharger and engine, and burning them off. This effect lasted no more than a couple of weeks, I would say. 

As regards fuel economy, I have not carried out the brim-to-brim tankful type test, but I have been closely monitoring the indicated mpg values on the dashboard display. The biggest difference that I have noticed is when towing the caravan, when previously I would achieve indicated values of 30 to 33mpg on a longish run, but I now get a consistent 35 to 38mpg display. Similarly, without the caravan on the back, I could previously expect up to between 55 to 60mpg without too much trouble, but I can now achieve 60mpg plus quite regularly. I know that these indicated values are not accurate in themselves, but I am hoping they are indicative of a proportionate real-world improved economy.

Regarding any potential increase in power resulting from the higher Cetane value of the diesel with its additive, I have no means of knowing for sure. My sons tell me that my normal driving style is “Grandpa Mode” as opposed to “Boy Racer”, which may account for the mpg figures above, and it means that I have not specifically noticed any increase in power. However, I am presuming that the improved mpg values above, particularly when towing, are due to a slight increase in power, as well as a cleaner engine. 

Interestingly, I found out recently that one of my sons, who ran an ageing Astra 1.6 with a petrol engine for many years, used an equivalent petrol additive in his car for about a month before every MOT test, and the recorded emissions results each year would be virtually zero! Needless to say, when my Passat is due for its MOT in January next year, I will be comparing the emissions with those recorded this year, before I started using the Millers additive, and I will update you with the results then. But here’s a bit of lateral thinking for you – if all diesel car drivers started using an additive such as Millers Ecomax above, or started buying the premium grades of diesel, would that improve air pollution overnight? Obviously, drivers would not buy premium diesel unless some adjustment was made to the cost – increased sales volume and all that. No doubt that is “pie in the sky” thinking – if only things were that easy! 

I look forward to receiving your comments, but in the meantime keep up the good work. I always look forward to reading your section of the magazine each month. 

Best wishes,

Richard Adams

Hello again Richard. 

It is indeed an amazing six months since we last communicated. How time flies! I am most grateful to you for your follow-up to the previous exchanges. It’s rewarding that so many readers do take the trouble to come back some time later, even when my advice has possibly not solved a problem – it’s not unknown! 

“Overjoyed” is possibly a touch OTT regarding your experiences with Millers Diesel Power Ecomax, but it’s indeed really good to see your figures, and proof that good quality fuel additives are more than cost-effective. It was interesting to hear about the “certain aroma”… I have not heard such things reported before, but I would not argue with your suggestion of burning soot. 

So you are reporting effectively around 5mpg plus fuel economy benefit. Great. That’s around a ten per cent saving and, even on your modest 6,000 miles a year, is a saving of over £60 a year, and the benefit of knowing that your engine is clean and in good shape. Of course, whether or not (as some disbelievers might jokingly suggest) some of the gain is possibly even psychological really matters not – a bit like homeopathic remedies! If it works, for whatever reason, then don’t knock it. Excuse my offbeat sense of humour! 

When you speak of the reduced pollution benefits of additives and premium fuels, one has to bear in mind the relative costs of the two alternatives, of which you are obviously aware. My calculations usually expose premium fuels as costing effectively around two to three times as much as using your own additive, like Millers or Wynn’s, which are also excellent products. I say this strictly in relation to diesel though, as I tend to think that high octane premium petrol is possibly a better buy than premium diesel, in cars with higher performance petrol engines that benefit from the extra power and engine efficiency possible, when the engine is able to take advantage of the high octane rating. More ordinary petrol cars may show no benefits whatsoever though, if the standard fuel is of good quality, and has reasonably good detergent properties. 

Apologies if you have told me previously, but do you use supermarket fuel, branded fuel, or a particular branded fuel? Anyway, Richard, I hope that your MOT emissions test confirms the evidence (although MOT emissions testing is relatively very crude) that Millers Diesel Power Ecomax continues to perform, and that Diesel Car continues to please and entertain you! 

My very best regards, 

Doc D

The dreaded black smoke, and more!

Hello Doctor. 

I wonder if you can give me an opinion on a problem. I recently bought a 2006 Volkswagen Transporter T30 Window Van, with the 2.5 TDI PD engine. The van has done 145K miles, but doesn’t seem to have done a lot of work recently, and it takes a bit of starting up sometimes, and is very chuggy when it first gets going. To be quite honest, it’s really a bit chuggy much of the time, and it blows out a bit of smoke too. I guess I’ll have to get that sorted before the MOT comes up!

But the strange thing to me is that after a decent long run, the engine sometimes tends to “run on” a bit when you turn the ignition off, and it’s a bit disconcerting, and once or twice I have had to stall the engine by dropping the clutch in. Have you any idea for what might be the cause of this phenomenon? 

Geoff Hardy,
Willenhall

Nice one Geoff! I rather do like a different challenge, and some of the older vehicles are far more interesting than newer ones. I just hate just saying “You need a diagnostic check”, although sometimes unfortunately that has to be a starting point, after I have maybe offered a few hopeful possibilities. Anyway, to the point. Running-on is pretty rare these days, and the source of the problem is fuel (of some type and source) continuing to feed into the engine when you turn the ignition off. Now there are two possibilities for fuel and those are obviously diesel fuel, but also possibly lubrication oil, which can burn quite well in a hot diesel engine. I’m also concerned about your black smoke, as you are not going to get an MOT pass with any visible sign of smoke!

Let’s look at the running-on side of things first. The only possible way that I can really think of this happening is if the fuel shut-off solenoid is sticking open, or partly open. Now I know this could, and did, happen with older diesel engines, but I’m not sure whether on your engine there are not other ECU electronics that should prevent diesel fuel actually getting into the cylinders, as the 2.5 TDI PD is a bit of an in-betweener technology-wise. Unless you’re into auto electrics, you need to get this checked out at any competent garage that can track down where the fuel solenoid is located, and see whether it is functioning as it should. That would be an easy and relatively cheap solution.

Otherwise, we might be looking at two possible sources of lubrication oil getting into the cylinders. One is direct from the oil sump, with the aid of a bit of “blow-by”, or more likely via the crankcase breather that recirculates crankcase fumes back into the air intake, although the engine would probably need to be in a pretty bad state for that to happen. The other possibility is via the turbocharger, if the oil lubrication there is leaking oil into the air side, perhaps due to worn bearings and/or an oil seal that is not sealing properly, although generally most of that oil ends up in the exhaust side, and shows up as black smoke – typical signs of a shot turbocharger. Oh! You did say your engine was a bit smoky, did you not…? Hmmmm! 

Finally, might I just mention another possibility, although one not relevant to your engine, as it does not have a DPF filter. (Well, I’m pretty sure that it does not, as I think they were not fitted to 2.5 TDIs for another year or two.) But a later Transporter model might well have DPF problems, when the extra fuel injected for DPF regeneration can end up in the sump oil, if things go wrong and the regeneration system is at fault. In that case, you would be able to spot this by the oil level in the sump rising, beyond the normal maximum level. When engines run-on in this situation, things can get very nasty, as it can be very difficult to stop them. 

To be honest though, I think your problems, both the running-on and the black smoke, are most likely turbocharger related, Geoff. I fear that you might well need a new one – or maybe a reconditioned one – see the mention of the excellent reconditioning service offered by Turbo Technics in another letter in this issue. 

I hope my words are of some assistance Geoff, and best wishes for your Transporter’s health, which I hope can be improved. It’s a really nice engine, that 2.5 TDI, when running well, and it makes for a Transporter with a bit of urge, yet is still pretty economical. 

Best wishes, and let me know how you get on, if possible! Best regards, 

The Doctor 

Electric Resistance

Greetings Doctor Diesel. 

I have not written to you before – over eleven years of being a Diesel Car reader – but I cannot resist raising the subject of conversion to electric power that you have touched on several times in recent issues. I’m a dyed-in-the-wool diesel man and, like others who have written in, I can see no future in big volume electric car sales – well, at least until the running cost advantages, if there really are any, are clarified for the foreseeable future. An electric car is “not just for Christmas”, or next year, for that matter, and from what we are told they are going to last a long time, if the promises of continually improving battery technology hold up. But if the “electric deal” were to turn sour, like the diesel one has done for many thousands of diesel car owners, who now have to pay extra costs for access to cities, parking in them, and parking outside their own houses, there may be riots in the streets. And the riots may not be about outrageous electricity prices when bought from motorway fast charging units, or when some heavy taxation starts getting imposed, but because people can’t find an empty charging point in their street, or the whole electric supply system trips out because it is overloaded. Of course it’s quite easy to make electric cars, expensive though they still are to buy – they look cheaper to run now than they may become in future, with purchasing subsidies, zero employee company car BIK taxation, and zero vehicle excise duty – not to mention cheap electric “fuel”. But how long will that sort of deal last? How many of these tasty incentives are driven by the nigh impossible EU targets for reducing carbon dioxide emissions, that just cannot be met with today’s fossil fuel cars. 

Frank Thompson,

Cleethorpes

To be perfectly frank, Frank. I’m in significant agreement with many of your points, but I can also see why things are (sadly) happening the way they are. The big factor is the matter of carbon dioxide emissions reduction targets that the big manufacturers are having to address. Their target, in terms of their own effective corporate averages emissions, is to cut these emissions as quickly as possible, and that is by replacing big, heavy, thirsty, petrol and diesel MPVs, luxury saloons and hatchbacks by electric equivalents. It’s simply the quickest way to get those carbon dioxide emissions down. Plus, with battery supply problems, and battery technology constantly bringing improvements, the manufacturers (apart from Tesla) cannot, and do not want to, get into bulk volume battery electric models yet. They need time to develop the new electric power based platforms to build into new ranges of cars, a bit of time to wait for battery technology to move on, and battery prices to drop, and it’s all taking time to happen, is very capital intensive, and won’t provide quick profits, particularly at the lower end of the market. 

But I have also seen a paper produced by the respected emissions measurement specialists Emissions Analytics, and they have a somewhat different opinion from the Government, and the EU, that suggests that we are attempting to move too fast, and too early, into pure battery EVs, in the chase for lower carbon dioxide emissions. They feel that a gradual transition via mild hybrids and full hybrids is a better way to use what battery manufacturing capacity exists, and this would take the pressure away from electric vehicle range obsession and the panic demands for thousands of on-road fast chargers. It would also offer better chances of reducing carbon dioxide emissions in the immediate future. I might add that the sort of owners/drivers who are demanding fast charging facilities are not your typical motorists, and their EVs may be producing nice, helpful, carbon dioxide numbers on paper for their manufacturers, but these open road, high annual mileage drivers and their electric cars are doing very little at all to reduce urban pollution. 

We can wait a few years for conversion to electric power, and the charging networks to go with it, but the problem of urban pollution needs urgent action now. It may be a somewhat unsubstantiated comment, but a friend of mine who visits London very frequently says that he is seeing fewer and fewer private cars on the streets, but still plenty of dirty, smoky taxis and buses! 

Best regards,

Doc