Looking after a diesel engine, modify driving patterns?

Zoney

I've read before diesels aren't great for frequent short trips, and with my first diesel I've certainly been surprised at just how long it takes the engine to heat up.

I'm curious as to just what constitutes unsuitable and suitable driving patterns, given I would have been happy with a petrol engine again, as mileage is probably only about 8k miles a year.

To start with, usually have a one or two long trips a month (1-2hrs min, mix motorway and N/R road), so maybe regardless, this is enough to keep it in top shape?

What about longer cross city trips where the engine shows as being fully heated up by the end, and you are at off peak times so not much start stop. Does this help make up for shorter trips? Or is 4th gear out of 6, at 50 km/h and only say 10 mins driving at full engine temp not enough? Does it help to drive motorway speeds on the ring road instead of through city, or is this worse due to the engine being cold to start off?

What about when the engine is cold and you're making a 5 minute trip (so short but again not really start/stop). Does it help to drive more gently? How many trips like this are OK before a bigger trip is needed to clear things out?

km991148

I *think* the theory is this:

Any trip from cold should start of with a few mins of non aggressive driving - you want to have the engine working to allow it to heat up faster (than for example idling at slower revs).
This applies to any engine petrol/diesel etc

For diesel specific cars the main issue with constant short cold trips is the diesel particulate filter - you need to have hot exhaust to burn off what is caught in the filter. If you never get hot exhaust (which takes longer than getting the engine up to temp) then the filter clogs up and will need replaced etc

There are probably a ton of other issues as well, but those are the main ones..

But basically a blast every month on out of town roads is plenty and go easy when its a cold start.

corkgsxr

I have a van so no choice but diesel. And spend most of my time back and forth across the city in 15/20 min bursts

I spend half the year with half my grill blocked.

Long trips it doesn't need the airflow.

Short trips it warms up faster. If it heats up too much radiator isn't blocked so fans can drag it though.

I've done it with big and small vans never a bother.

If it stays over about 15 degrees on average I take it off.

Dartz

Once it's up to running temperature, don't be afraid to give it a good battering every now and then on the shorter journeys. Get all the temperatures up inside the engine - get hot combustion happening, get the turbo wastegates moving and all that. Clears the ****e out. Oil pressure goes up, bypass valves open, particles of carbon get pulled out.

It could be somethiong as simple as sinking the shoe on joining the motorway and letting it rev out as far as it'll go before shifting to the next.

A good shoeing does help your engine. Once you're inside the rev-limit and you're temperatues are okay, working the engine will never really harm it.

Unless there's something structurally wrong with it, in which case a good hard shoeing will find it very quickly

jca

Dartz wrote: »

Once it's up to running temperature, don't be afraid to give it a good battering every now and then on the shorter journeys. Get all the temperatures up inside the engine - get hot combustion happening, get the turbo wastegates moving and all that. Clears the ****e out. Oil pressure goes up, bypass valves open, particles of carbon get pulled out.

It could be somethiong as simple as sinking the shoe on joining the motorway and letting it rev out as far as it'll go before shifting to the next.

A good shoeing does help your engine. Once you're inside the rev-limit and you're temperatues are okay, working the engine will never really harm it.

Unless there's something structurally wrong with it, in which case a good hard shoeing will find it very quickly

Give her the holly Molly. Spoken like a true rotary engine driver, I like It!! Get the cobwebs out of her.

Dartz

The beneficial effects of a good Italian tune have been well documented.

Guy:Incognito

Turbos (in general , not just diesels) need a bit of looking after. Dont just kill the engine straight after stopping , let it spool down.

I'll let any engine get the oil to temp before any sort of hard revving,

honda boi

Short journeys wouldn't be as bad with diesels without a dpf would it?

Marcusm

honda boi wrote: »

Short journeys wouldn't be as bad with diesels without a dpf would it?

Only for people with asthma or COPD.

mikeecho

Diesel engines work best when working at a constant speed (revs)
So lots of stop /start, and irregular speeds wont give the best efficiency.

So. to get the best from a diesel, long trips, and a constant pace will return the best fuel economy.

Tuco88

Stop/start technology imo is the most useless system ever to be placed on a Diesel engines. A great idea if you have 2/3L petrol.

Along with the Dpf/ERG/ addblue carry on.

mikeecho

Tuco88 wrote: »

Stop/start technology imo is the most useless system ever to be placed on a Diesel engines. A great idea if you have 2/3L petrol.

Along with the Dpf/ERG/ addblue carry on.

Stop/start is a pet hate of mine.
I always disable it, .. even in rentals..

Mycroft H

I throw some redex fuel additive into the fuel tank every so often. It must clear some crud out as it does feel more responsive afterwords.

jca

Mycroft H wrote: »

I throw some redex fuel additive into the fuel tank every so often. It must clear some crud out as it does feel more responsive afterwords.

First fuel additive post, took longer than I thought.

dok_golf

jca wrote: »

First fuel additive post, took longer than I thought.

You don't agree with the additive?

Ciano35

Worth noting that oil takes a bit longer than coolant to get up to temp. So don't start ragging it the second the coolant gauge gets to normal temperature.

ION08

jca wrote: »

Give her the holly Molly. Spoken like a true rotary engine driver, I like It!! Get the cobwebs out of her.

Yeah, that really keeps them in tip-top shape... for about 60k miles until you need to rebuild the engine :rolleyes:

That must be they key to Rotaries reliability and longevity!!

Mycroft H

dok_golf wrote: »

You don't agree with the additive?

It lowered the emissions noticeably on a NCT retest for me. About 10-15% percent.

For how cheap they are, I don't mind throwing a bottle in a few times over the year.

markpb

I've a 7 year old 2 litre Insigna and the DPF gives me nothing but problems. Admittedly the car isn't suited to my driving but I really do like the 163bhp...

I do the normal twice-daily short trips in traffic which everyone knows will cause problems but twice a week, I drive from Sandyford to the airport round the M50 at off-peak time and I do at least 100kph in 3rd gear. About every 6 weeks I drive to the midlands or west and I'll do at least an hour of that trip in a low gear. Despite all that, the DPF never regenerates and I'm on my second static regeneration in as many years. I've tried Wynns DPF cleaner and Dipetane and neither of them seem to do any good.