XUD9 DHY

[SvenBX]

Hello all,

i have a 1987 Citroen BX 19TZD Turbo with a XUD9 DHY engine from a second gen Peugeot 405.

The question is, when driving 130 on the highway it likes to raise the engine temps to around 90 and when going up a hill for a longer period sometimes it jumps up to 95 or higher so i stop to let it cool off.
The thermostat is new and its specifications are 83-87.
The waterpump is new and the cooling system is flushed.
The fans kick on low speed around 89 do 91 and the second speed even higher id say around 95.

Ive noticed smoke when more then 3/4 throttle grayishly black coming from the exhaust and ive noticed my fuel consumption going up, best guess i need to get my bosch diesel pump rebuilt or should i first try getting it factory tuned since i can see it has been fiddled with before.

Thanks

[mickthemaverick]

We have some very knowledgeable members on your engine and I'm sure one of them will offer some advice soon. The temperatures do not sound wildly out of kilter to me, but I'm no expert. I would suggest you get a global scan done if your car was newer but I believe that is pre OBD technology so you would need a specialist diagnostic from one of the early kits, which do exist among the membership !! Good luck

[Stickyfinger]

The temps sound OK to me.....(I run a 1.9td 1993 Xantia).
Old school oilers all make "some" smoke, I notice it on acceleration some times as well.

I have had good results from dumping a full bottle of Wynns Diesel Cleaner into a 1/4 of a tank and then topping up to a 1/2 tank when very low and adding another bottle of cleaner...

[SvenBX]

Thank you all for the responses and warm welcomes, i dump an entire bottle of injector cleaner into my 66L tank once a month since i do around 10.000km per month. (its a BX with the extra tank in the rear bumper).
Its my daily driver and workhorse.

im doing my best to keep that bosch pump running as healthy as possible, but it used to do 1200km on one tank now it does around 900km and ive been noticing the smoke from the exhaust lately.
Il still get it checked by bosch pump specialist since i work in a company that has that department (They already rebuilt and retested the injectors).

This is giving me some assurance that its probably a healthy engine then, i replaced the stock A8A engine (XU7TE) because the car sat for 18 years before the restoration and the headgasket gave out (mixed oil and water under highway driving).

All suggestions are welcome

[myglaren]

My first thought is some restriction in 'breathing'. I'm sure that you will have checked/replaced the air filter but perhaps there is a restriction somewhere, a collapsed hose. The hoses do soften in time and collapse, at least partially, when the engine is running.

[SvenBX]

The hoses are newish but it could be the turbo is sticking or not spinning up enough, now that you mention it is it normal that boost comes in around 2500rpm?
I know old diesels have a large amound of boost lag but 2500rpm is high for a large displacement diesel isnt it ?

Il check the wastegate and the turbo this weekend when im restoring the front calipers.

[ekjdm14]

Welcome, that does sound a bit on the high side for boost to be building. We had good boost on our (recently, and violently!, departed) DHY engine in a 306 from under 2000 rpm, and probably full boost before 2500rpm. It would be worth double checking the intake for any issues as you've noticed the economy getting worse and the smoke.

Also may be worth checking the exhaust for any restrictions if your running temperatures are higher than usual (although I'd agree the numbers sound normal to me, would only worry if it continued climbing above 105c under normal driving) as a collapsed baffle could restrict flow.

Hopefully it's something simple like that.

[SvenBX]

Yesterday i fixed my tacho sensor and rebuilt my front calipers and put premium diesel in the tank.... (2.2 EURO PER LITER are they mad?!)
NOW the car runs better then ever, no smoke(guessing the pump needs tuning since it runs better on premium diesel), the coolant temps are lower (150kmh on the highway and they are steady around 87), more power but boost still seems to start building around 2200 RPMs and its at full boost around 2600 RPMs.
When i checked the turbo i didnt see any excess play and it spins freely and the intake piping leading to the top mounted intercooler is tight and newish with 0 holes, but there is a small amount of oil leaking from the intake side fauling up the rear of the engine...
il keep an eye on my oil level.

[ekjdm14]

Oil leaking from the intake would suggest a boost leak to me, there's always a small amount of oil in the pipework even with a healthy turbo so I would concur that your turbo is reasonably healthy, just that there has to be a small leak for the oil to be blown out.

Other than that, I'd say maybe check/change the fuel filter and if you have the pin tool & a dial gauge double check the pump timing but doesn't seem too unreasonable as long as it's starting well and no grey smoke.

[SvenBX]

Its leaking from the intake side of the turbo so i would say its probably fine then, i havent had the time to check since ive been dealing with other family matters.

Regarding the pump : Sometimes it starts fine right away no cranking at all, sometimes it takes around 3-5 turns to start and when that happens it spews out gray smoke.
Sadly i dont own a pin tool or dial gauge.

The fuel filter is changed every 10 000km since its a car thats been sitting awile and i dont want to ruin the pump.

[Stickyfinger]

Some smoke is expected on starting , esp if cold/a few cranks....if the amount worries you ....maybe run a check on your glow plugs, one maybe down.

[Mihael_M]

Hello, I would go back to the first post. You say that the thermostat is new and for temperatures of 83-87. Thermostats are generally sold for a nominal opening temperature in your case it should be 83 C. When the thermostat opens, the temperature after that depends on the operating conditions. With better fuel, the engine achieves greater efficiency and that is why the temperature does not go above 87 C.

[SvenBX]

Glow plugs were replaced when the engine was replaced, but i will check them before winter when the car is going for a bit of a rework, i need to repaint the front bumper, hood, right side door and the gearbox need a rebuild.
Regarding the thermostat, on the catalog when i was browsing the thermostats it says their temperature values, for the current one it said 83-87 my best guess is 83 is when it starts opening 87 being fully open.
When i was browsing thermostats i was looking for the lowest temp one i could find.

I feel like the car accelerates better when around 3/4 throttle then full throttle, also ive noticed when driving the car around town for a few hours and then going for a proper drive with more throttle it loves to smoke alot.
Im guessing its normal since it clears up after a few harder accelerations, thing that worrys me is the grayishly black exhaust smoke when above 3/4th throttle and increasing fuel consumption.
(Premium diesel did not fix the 3/4th throttle thing just that the car felt more alive then didnt smoke as much and it was not as sluggish).

Could also be the fact this is my first Diesel ive driven (relating to the acceleration) other then the 84 TRD (Lucas pump and it never smokes no matter the throttle and doesnt rise temps above 85) but thats N/A so its not really comparable.

[citroenguy]

My 1.9TD Xantia -96 (Bosch pump) also is very gutless under 2000rpm. Also the 3/4 throttle thing also sounds familiar.
And mine also goes up to 90° for a bit when pushed harder