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Old 30th August 2017, 12:09   #1
mmz
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Default 75 CDTI engine problems

I really would like to get my 75 CDTI to run smoothly but it seems to be quite difficult. Do the following symptoms tell something to somebody more expert than myself?

- engine vibrates too much at idle even when warm
- fuel consumption is around 7 l/ 100 km at normal highway speed
- turbo seems to come along quite late
- engine feels a bit powerless especially when accelerating from a standstill
- in practice you can not use 6th gear below 60 km/h due to lack of torque
- heavyish buzzing sound from somewhere in the engineroom when driving and putting on power
- engine "rumbles" and vibrates slightly on highway when putting on power at speed (like the mountings were broken which they are not)
- fuel moisture at the bottom of cylinder one injector
- cleaned EGR and inlet manifold pressure sensor with no effect
- replaced MAF and air cleaner with no effect
- replaced fuel filter with no effect
- replaced engine temp sensor with no effect
- engine temp stays at "eight a'clock" except only when idling for a longer time e.g. in a traffic jam
- TOAF live data shows that injectors 1 and 3 are correcting flow values more than others when idling

There are no local Rover garages with analysers here anymore and others seem to be a bit reluctant to take my case. Rover really seems to be a dead and gone brand outside UK nowadays.
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Old 30th August 2017, 12:51   #2
steve-45
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Is it a manual or auto?

Not sure that either has a 6th gear ?

Also, if temperature gauge is only getting to the 8 O'clock position it sounds like its running too cold and maybe needs a new thermostat.
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Old 30th August 2017, 14:28   #3
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Hi Vesa.
Have you checked the intercooler O-ring, also intercooler hose these get less effective as they get older, if the hose looks like it is swollen or is sweating personally I would change anyways, engine vibrating at idle is most likely the lower engine mount.

Check also all the vacuum hose going to and leading from the EGR solenoid do a leak back test on the injectors once the above have been checked if no change.

With regards to your engine temperature it sounds like your thermostat is opening early therefore you would benefit from either changing it, or doing the inline stat mod, check the true temperature of your engine after a good 10 to 15 miles drive up hills if you can also, by using the OBC 19 then 7
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Old 30th August 2017, 23:57   #4
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Quote:
Originally Posted by mmz View Post
I really would like to get my 75 CDTI to run smoothly but it seems to be quite difficult. Do the following symptoms tell something to somebody more expert than myself?

- engine vibrates too much at idle even when warm
- fuel consumption is around 7 l/ 100 km at normal highway speed
- turbo seems to come along quite late
- engine feels a bit powerless especially when accelerating from a standstill
- in practice you can not use 6th gear below 60 km/h due to lack of torque
- heavyish buzzing sound from somewhere in the engineroom when driving and putting on power
- engine "rumbles" and vibrates slightly on highway when putting on power at speed (like the mountings were broken which they are not)
- fuel moisture at the bottom of cylinder one injector
- cleaned EGR and inlet manifold pressure sensor with no effect
- replaced MAF and air cleaner with no effect
- replaced fuel filter with no effect
- replaced engine temp sensor with no effect
- engine temp stays at "eight a'clock" except only when idling for a longer time e.g. in a traffic jam
- TOAF live data shows that injectors 1 and 3 are correcting flow values more than others when idling

There are no local Rover garages with analysers here anymore and others seem to be a bit reluctant to take my case. Rover really seems to be a dead and gone brand outside UK nowadays.


The engine vibration described is a classic description of bottom engine mounting failure. I would recommend you change the bottom engine mounts bushes both the big one and the small one.
Personally I would fit polly bushes.

There is no Diesel Rover 75 with a six speed gear box as standard, if yours has a six speed box, I would investigate the mounts on the conversion. If it is a Six speed box please check the gear ratios as the box may have ratios incompatible with the turbo range on finial drive ratio. The 75s Diesels turbo range is quite a tight band. I.e. Comes in late drops out early. Very different to Ford and Vauxhall.

The Diesel engine fitted to the 75 is a very good example of a high torque over a wide rev range. The lack of torque you describe sounds like an intercooler hose rigidity problem. Again I would recommend changing the intercooler hoses. These are available in quality multi ply silicone, I would recommend changing the intercooler hoses for quality new ones. Once the turbo can breath with out change of hose diameter I think you will notice a difference. Personally I would also run the intercooler through a parts bath, making sure all the grunge and crud is removed from the inside of the unit.

The description of engine temperature sounds like a thermostat problem the Diesel engine in these cars is a naturally cold running engine. I would replace the engine thermostat with a new unit if that fails to bring the engine up to correct engine running temperature, then a popular way to fix this problem is to fit a Renault 5 in line thermostat in side the top radiator hose. This is done in tandem with the existing Rover thermostat. Either fit an 88 or a 92 degree thermostat from a Renault 5, this supplementary thermostat will ensure the engine reaches correct running temperature.

The BMW diesel lump we have in our cars perform much better when at the correct temperature if the car is running cold when you get it up to temperature you will notice a marked decrease in the amount of fuel used. Possibly as much as an extra 70Km on a full tank of fuel.

I personally drive Rover 75 Diesel automatics. The estate is my main tow car. It is a 158 Bhp remap. When towing my 1.4 tonne caravan I use sports drive. As it shifts the rev band more into the turbos operating range, for pulling the extra weight. She does this returning 8.7 ltrs / 100 km. running without the load she returns about 7.7ltrs/100km.

My saloon is remapped to 135 Bhp my wife uses her about town only she returns about 7.8ltrs/100 km.
Both my wife and I love our Rovers, don't know what will be the following act hopefully I will have them for another fourteen years.
By which time it is doubtful if I will still be driving. That age thing again.

Hope you get your problems sorted soon. Once you have her running smoothly you will see why so many of us love our Rovers
A very hard act to follow.
Alan



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Old 31st August 2017, 07:41   #5
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Sorry, of course there are only 5 (manual) gears and thus I meant that for some reason there is not enough torque to drive at the topmost gear in town. My previous car was Citroen C5 1.6 diesel and compared to that this Rover feels quite anemic overall.

I have renewed the upper hydro mount and tried a new original lower mount, but the latter made things even worse being too stiff and thus conducting the engine vibrations straight to the body.

This morning I noticed a couple of new symptoms. The engine is jerking slightly at steady 70 km/h before it gets warm and when getting hot in town traffic it starts to misfire like one of the cylinders were temporarily out of the play.

The thermostat and intercooler hoses/seals might be the next things to do. Running at the right temp might improve things and the intercooler hose before the EGR seem to be oily on the outside and quite soft.

Thanks for help. Hope this car will soon be as good as it should be.
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Old 31st August 2017, 08:02   #6
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Does someone know the exact diameters of the intercooler hose o-rings? It would be easier to buy them at some local shop than to order them from abroad.
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Old 31st August 2017, 14:17   #7
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Quote:
Quote:
Originally Posted by mmz View Post
Does someone know the exact diameters of the intercooler hose o-rings? It would be easier to buy them at some local shop than to order them from abroad.
Vesa you need to use Viton O-rings as they are not susceptible to the oil, i supply & fit these for free at our local meets, with regards to the vibrations seeing that you have changed the lower engine mount and the hydo mount look to the lower wish bone bushes, check them out.
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Last edited by Arctic; 31st August 2017 at 14:19..
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Old 31st August 2017, 17:32   #8
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7 l / 100km = 40mpg if it's an auto and being driven around town then it's in the normal range. Getting it up to proper temperature should improve the fuel consumption a bit though.

60kmh is just under 40mph and should be achievable on a level road in top gear (fifth!). However it won't be the smoothest particularly if you have worn engine mounts or uneven injector balance. Don't expect much performance from it in top gear at that speed. One other cause for engine vibration is the crank pulley if it is showing signs of wear it can cause more vibration.
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Old 31st August 2017, 20:02   #9
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When I first bought Kim - 2.0 cdti - I was coming back from Barnsley and accidentally left it in 5th gear, at 30mph going up hill. She didn't like it. Plus there was a blatant vibration around the 1500 rev mark.
I know I need to replace the lower engine mount, but I found that putting a bottle of fuel injector cleaner into a quarter tank of fuel then filling up, resulted in a noticeably quieter and smoother ride, despite the vibrations.
My thermo hardly ever gets past 8 o'clock too so I'll be looking for a new thermostat.
After treatment of the fuel system I got uphill in 5th at daft mph, dropped to a lower speed to allow other cars to pass, then easily picked back up to daft mph. It made a big difference
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Old 31st August 2017, 20:14   #10
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Try some injector cleaner in the fuel. it might get rid of that slight misfire you are having. Try the cheapest options first.

If no success then you might have to have a look at the injectors.
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