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Diesel MoT fail
cliftyhanger - 2/3/21 at 05:55 PM

Not mine, but sister/BIL 2008 mondeo TDCI thing. No DPF as far as I know
It has just failed the MoT on smake. Recorded 56, the limit is 50 (so I am told)
They have not used it for months, but I have., Took it for a 400 mile trip back in November, then just last week used it to collect a car using a trailer, about 150 miles. However, what I did was chuck a couple of bottles of redex cleaner stuff in the 1/2 tank before setting off, and used the rev range to try and get it running clean. I also fitted an EGR blanking plate (no lights)
BIL took the car for a 25mile run (I doubt thrash) before the MoT.

I will suggest an air filter and fresh oil (why does fresh oil help?) and maybe let me "drive" the car to the MoT retest.
Any other suggestions?

(and yes, wrong engine for them, he rarely goes out of town, and doesn't like to go above 1500rpm if he ca help it. A candidate for an electric car I reckon)


Mr Whippy - 2/3/21 at 06:19 PM

I did use cataclean to get the wifes tdi through the MOT but it's always something with a diesel, like flogging a dead horse.


coyoteboy - 2/3/21 at 07:05 PM

Egr blanker may not have helped, recirculating the soot tends to reduce it further. If it is blanked it just goes out of the tail.

With no scientific backup.... Oil makes no odds unless you're burning oil in quantity. If it has sat for a time, even a week, the soot more readily parts ways with the inside of the exhaust.

First time I fire my D up after a week it spews a cloud. Rev the crackers off it (loaded) on the drive to the test. That's about all you can do, other than get the injectors checked out. And take the air filter out


coyoteboy - 2/3/21 at 07:07 PM

quote:
Originally posted by Mr Whippy
I did use cataclean to get the wifes tdi through the MOT but it's always something with a diesel, like flogging a dead horse.


My diesels pass without any hint of a problem? One at 250k miles, the other at 175k


nick205 - 2/3/21 at 07:28 PM

SWMBO and I have been driving diesels for years and never had an MoT fail. That said I like to "exercise" the cars now and then.


steve m - 2/3/21 at 07:38 PM

My old 2008 140 TDCI, never failed an MOT, but before every one, i would do a full oil change, and filters, also the month before tip a bottle of sea foam in the tank, and on the day of the MOT give it a good 30 mins blast down the M23

I also used to use premium fuel, in the lead up to the MOT,

I cant say7 if any of my actions helped, but the old Mondeo, never failed


steve m - 2/3/21 at 07:44 PM

The 2008 Mondeo Diesel, does have a DPF, and it does a self clean at random times, the other way is to get on a motorway leave it in 3rd and drive it with over 3k revs, i did this with 3.5-4k of revs for at least 20 mins

On a 2008 model, and probably others you can hear, feel and smell when the car is doing a Dpf clean, the car seems to shake, the AC fan comes on, and the exhaust smells, and if you boot it, it will leave a cloud of black smoke behind

steve


obfripper - 2/3/21 at 07:54 PM

quote:
Originally posted by cliftyhanger
Not mine, but sister/BIL 2008 mondeo TDCI thing. No DPF as far as I know
It has just failed the MoT on smake. Recorded 56, the limit is 50 (so I am told)
They have not used it for months, but I have., Took it for a 400 mile trip back in November, then just last week used it to collect a car using a trailer, about 150 miles. However, what I did was chuck a couple of bottles of redex cleaner stuff in the 1/2 tank before setting off, and used the rev range to try and get it running clean. I also fitted an EGR blanking plate (no lights)
BIL took the car for a 25mile run (I doubt thrash) before the MoT.

I will suggest an air filter and fresh oil (why does fresh oil help?) and maybe let me "drive" the car to the MoT retest.
Any other suggestions?

(and yes, wrong engine for them, he rarely goes out of town, and doesn't like to go above 1500rpm if he ca help it. A candidate for an electric car I reckon)


If the plate value is 0.50 it will have started life with a dpf, they are a common failure on those engines across the ford range.
If you run your finger around the inside of the tailpipe and it is sooty, it is a sure sign the dpf has failed, they usually crack the carbide matrix and let the unfiltered gas out.
If the filter has failed or has been removed, the only means of sorting it is a replacement unit. A genuine ford one is too expensive to consider, the aftermarket ones will pass an mot but jurys out on how long they will last in the long run.

If the dpf was just blocked (usual symptoms:no smoke, but engine in limp mode permanently), it could be cleaned back to new spec (similar cost to aftermarket replacement), however cleaning a failed unit is not worth bothering with, the smoke will be the same afterwards.

Fresh oil may do just enough to sneak under the limit but 0.56 is a good figure for a tdi, most non dpf models will be in the 0.8 - 1 region in perfect condition.

Dave


cliftyhanger - 3/3/21 at 06:04 AM

quote:
Originally posted by obfripper
quote:
Originally posted by cliftyhanger
Not mine, but sister/BIL 2008 mondeo TDCI thing. No DPF as far as I know
It has just failed the MoT on smake. Recorded 56, the limit is 50 (so I am told)
They have not used it for months, but I have., Took it for a 400 mile trip back in November, then just last week used it to collect a car using a trailer, about 150 miles. However, what I did was chuck a couple of bottles of redex cleaner stuff in the 1/2 tank before setting off, and used the rev range to try and get it running clean. I also fitted an EGR blanking plate (no lights)
BIL took the car for a 25mile run (I doubt thrash) before the MoT.

I will suggest an air filter and fresh oil (why does fresh oil help?) and maybe let me "drive" the car to the MoT retest.
Any other suggestions?

(and yes, wrong engine for them, he rarely goes out of town, and doesn't like to go above 1500rpm if he ca help it. A candidate for an electric car I reckon)


If the plate value is 0.50 it will have started life with a dpf, they are a common failure on those engines across the ford range.
If you run your finger around the inside of the tailpipe and it is sooty, it is a sure sign the dpf has failed, they usually crack the carbide matrix and let the unfiltered gas out.
If the filter has failed or has been removed, the only means of sorting it is a replacement unit. A genuine ford one is too expensive to consider, the aftermarket ones will pass an mot but jurys out on how long they will last in the long run.

If the dpf was just blocked (usual symptoms:no smoke, but engine in limp mode permanently), it could be cleaned back to new spec (similar cost to aftermarket replacement), however cleaning a failed unit is not worth bothering with, the smoke will be the same afterwards.

Fresh oil may do just enough to sneak under the limit but 0.56 is a good figure for a tdi, most non dpf models will be in the 0.8 - 1 region in perfect condition.

Dave


Ah, so I am mistaken about the dpf.
I try to avoid getting too involved with the thing, but as I borrowed it to tow a car recently I feel slightly obliged.
I will try a bit more cleaner stuff, some premium fuel, remove the air filter and change the oil. Then a good blast to clean it out.
No lights on the dash (except an occasional airbag light) so all seems to be well. And it is pretty close to a pass so I am hopeful....


McLannahan - 3/3/21 at 12:04 PM

My Passat of a similar vintage failed the emissions in style a few years ago. Local garage used this cleaner and it then ace'd it through and ran much better (and quieter) as a result too.

https://www.forteuk.co.uk/product/advanced-formula-diesel-treatment/


cliftyhanger - 3/3/21 at 12:41 PM

BIL just popped round to borrow a brake rewind tool and thankfully axle stands (rear pads) and was asking about a number plate bulb.
I had a poke at the exhaust, and my finger (!) came out with a slightly oily/black smudge. So not really sooty.

I encouraged him to fill with shell V power, pull the air filter out and change the oil. He seems to have free time today, wheras I have an appointment with a lathe and a bit of billet ali.

Is the Forte stuff any better than Redex? I do remember my old astra diesel, mid 90's failing on smake. I was told to use a can of forte, and just suck it neat from the tin. BIG smoke cloud but did the trick. Seems you can't do that these days.


McLannahan - 3/3/21 at 01:51 PM

They had a range of products on his shelves, including Redex but went straight for this one. I've lost a bit of faith in Redex products myeslf - I don't think they're as potent as they used to be and the brand seems a bit more watered down? Sold everywhere but not the best products in my opinion.


rusty nuts - 3/3/21 at 03:52 PM

Forte products were only available to the trade IIRC which may suggest they are better than products available to the public. I can say for certain that Forte products do what they say on the can


steve m - 3/3/21 at 05:34 PM

You can buy Forte on ebay, i always used seafoam, also on ebay

Any diesel engine needs a good Itallion tune up, as in thrash, there oil burners, so all that unburnt oil, will fill the exhaust up and you will have to get the whole thing VERY hot to get rid /lesson it, also if the owner of the car only revs it to 1.5k normally, the Dpf will be really full

From what i read when i had my Mondeo Tdci, was that the DPF only opens up to the exhaust at higher revs, so it can dump all the poo out the back on higherspeed roads, as in motorways

Low revs, as in town, the DPF is a closed ish system

I did mention up the page how to clear out a DPF, as in the 10 years i owned a coal burner, i must of had to blast up the motorway at 3.5k for at least 20 mins, probably 15 times

Dont leave the airfilter out, buy a new one, one little stone sucked up, and the turbo is finished, and possibly the engine

Might be worth sticking some cataclean in the fuel as well, but ive only ever done this on a Petrol engine, that required a cat, but didnt have one !!
super fuel, major thrash b4 the MOT and it passed emissions, despite being catless


coyoteboy - 4/3/21 at 08:34 PM

Haha never seen a stone in my filter housing, the torturous route to the filter takes care of that.

Also, check this out 🤣
https://youtu.be/cILFefqoIZc

Not using a filter long term is a bad idea, for the MOT is nothing IMO!


steve m - 4/3/21 at 11:41 PM

I destroyed my my turbo in my Xr4Ti by taking the filter off, i dont know what went in there, but the impellor was destroyed,
so much that when it spun, the turbo shook, so lol. as much as you like, it does happen


rusty nuts - 5/3/21 at 07:19 AM

quote:
Originally posted by coyoteboy
Haha never seen a stone in my filter housing, the torturous route to the filter takes care of that.

Also, check this out 🤣
https://youtu.be/cILFefqoIZc

Not using a filter long term is a bad idea, for the MOT is nothing IMO!


I had an Astra in for a service once that had the air filter housing full to the brim with pea nuts , apparently the customers neighbour fed the local tree rats


coyoteboy - 6/3/21 at 01:37 AM

None of which is applicable for an MOT test and trip too and fro, which is what was suggested.... Jeez folks


cliftyhanger - 6/3/21 at 06:41 AM

I happened to drop by BILs house yesterday to pick up my nephew (he has no work, but I needed a labourer!) to find him trying to change the rear pads. 5mins assistance had him sorted.
And I am using the mondeo on Monday to pick up my gearbox from BGH (only 4 months. And did give them a serious nudge on Monday, only to be told it was next to be built. Coincidence? Maybe)

Will chuck in whatever treatment stuff he has bought and the premium diesel he has filled with, an A/B road trip there so plenty of opportunity to floor it away from junctions/out of bends, and the M25/23 home I reckon with a little detour at the end with a cracking empty hill which was always my test track for checking modifications (ie what speed I could get to at the top of the hill)

Cheers all for the advice.
(and yes, no filter purely for the MoT)