The old SDI has been gradually losing mpg and generally feeling tired for the last four to six months. I've gone through all the obvious pointers to low mpg and power loss and decided to give the Terraclean treatment a go. Basically Terraclean is a fuel based decoke procedure where the car runs on a chemical concoction rather than diesel. The process took a good hour in the rain on my drive and cost a whopping £108. After the treatment I put a new main fuel filter on, and drained off the old one, which had no muck in the diesel what so ever.

My concern like many people, is that removing the crud from my 150,000 mile plus engine will cause more harm than good.

My initial five minute drive up the road, with me revving the life out of the engine resulted in a substantial cloud of blue and white smoke out of the exhaust. The car normally doesn't smoke, but does use 0.5 - 1 litre of engine oil every 10,000 miles I'm assuming this smoke was dislodged crud as it did die down to next to nothing over the five mile thrashing.

Initial impression on idle after the run was that the engine is noticeably quieter.

I'll keep this thread updated as I drive some more, and I'll see what effects if any the Terraclean has.

Update One:

So forty miles later with a solid motorway cruise at top speed...70mph. Instant mpg subjectively up a touch. Engine noise definitely less than the normal overall. Finished with an A road run, felt slightly more responsive, rev counter seemed to move a little more freely.

More power, no. More responsive, especially in gear, yes.

TBC...

 

 

Update Two:

 

Another forty mile journey combining motorway and fast A roads.  Engine noise definitely less.  Don't ask me how?  Smoother response when on and off the throttle in stop start traffic.  Definitely smoother in gear.  No problems so far.  No more power either.  I'll detail mpg when I fill up a whole tank, as anything less is meaningless.

 

 

Update Three:

 

Roughly two tanks of fuel later on identical day to day commutes and mpg has increased slightly. 

 

 

Still not back in the fifty's, but an increase of two to three mpg.

 

To date I've experienced no issues other than the initial smoke mentioned from having a Terraclean.

 

I'm unsure now whether the engine noise has continued to remain less.  I'm not talking a massive difference, but a noticeable one on the motorway, and also when lifting the bonnet (i.e. the injector pump).  Maybe I've just got used to the initial difference.

 

The engine definitely feels smoother still and slightly more free revving.

 

Did a Terraclean fix my issues with an economy drop.  No, I must still be missing something?

 

Did it benefit my car.  Yes, definitely feels and sounds fresher.

 

Did it cost too much.  In my case Yes, as it hasn't solved my issue.

I'd be interested in any updates on this. 180k+ on my engine and I would like a thorough clean out IF it has no negative side effects and is beneficial to the engine.

No lie, I was lucky enough to be present when a fiesta ST 2.0 with 60k was getting tuned, it had a tune 3 runs then a terraclean and the car yielded no more power what so ever.

 

I had my diesel terracleaned but was done before a tune.

Update One above.

trouble is , on a diesel it is not going to clean all the crap out of the inlet ports and around the valves which is where most of the oily sticky egr deposits gather, it may clean a bit of carbon off the piston crowns and from around the injector but that is about all, the smoke could have been oil burning off too as at idle the temps will be low and wouldn't burn any oil away that came past the rings while idling away for half hour, just think where are those bits of carbon going to go once the terraclean has loosened them off (if it does), answer, straight into your cat possibly causing damage to it.

snake oil I'm afraid guys but then I'm not the one giving away £100 or so  so just my opinion .

Absolutley not a great deal of use for a diesel, as you say typically inlet manifold and inlet valves are the bits that need cleaned and terraclean wont touch that.

felicia16v you are very much correct about the inlet side of things being where the muck lives. I've had the inlet manifold off in the last four months and it was a mess! The SDI has only two cylinders effected by carbon / oil. One is the outer cylinder nearest to the EGR which gets coked up. Two the outer cylinder nearest to the CCV, which gets oil vapour build up.

I cleaned the inlet manifold with the aid of petrol and a match, which worked wonders. The CCV is now routed through a catch can. I did blank the EGR off, but since the mpg started dropping it's now been removed.

The inlet on the engine block is indeed still mucky on the two cylinders mentioned above. I didn't fancy getting anything knocked down into the valves.

SDI EGR's don't block up anything like there TDi Cousins.

When the Terraclean was carried out the engine had been warmed up, (I'm guessing 85 degrees C) and the car was held (I believe) at 2000 rpm for the cleaning period twice.

Update Two above.

Felt like I had been robbed of £108.

have you checked the pump timing, it can make a massive difference to the fuel economy on these sdi's

Wouldn't chance it myself tbh especially on a high mileage car. It's ok if they can garentee everything to come out during the clean but if lumps start running through the engine after the clean it could cause major problems.

felicia16v I did a double check today...

 

 

I'm thinking not enough to make a double figure drop in mpg?  Thoughts?  (Other than my right foot.)

Update Three above.

Warmer weather increases MPG on diesels.

Yea pump timing looks alright, bit advanced but nothing to worry about. Checked the egr operation etc ?

When I get another chance I'll double check egr, maf and such.

 

I'll report back...