Ford Mondeo diesel - knocking from engine on start up from cold

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Thu 9 Sep 2010 09:58
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

hi,

i have a 1998 mondeo diesel, it has been very reliable and has covered 126000 miles. recently it has developed a loud knocking/clattering noise from the engine when starting from cold . when i press the accelerator there is no response for about a second and then the engine will run as normal. when coming off the revs and when it settles into tickover the knocking will come back, but as the engine warms up the noise will gradually quieten down and disappear. the car will then run fine throughout the day, and when left for a few hours will continue to start and run fine with no problems. the knocking only happens when left for several hours, or overnight.

any ideas gratefully appreciated.

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Thu 9 Sep 2010 12:01
Ford Mondeo diesel - knocking from engine on start up from cold - Peter.N.

Sounds as though the pump timing is over advanced when you start from cold. Do you get any exhaust smoke when it happens, if so what colour?

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Thu 9 Sep 2010 13:07
Ford Mondeo diesel - knocking from engine on start up from cold - madf

More likely to be a stuck tappet..?

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Thu 9 Sep 2010 14:07
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

Sounds as though the pump timing is over advanced when you start from cold. Do you get any exhaust smoke when it happens, if so what colour?

exhaust smoke is no different than it always has been. grey/blue in colour. usually chucks out a big plume of it from cold and then clears for the rest of the day.

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Thu 9 Sep 2010 20:57
Ford Mondeo diesel - knocking from engine on start up from cold - Peter.N.

Does it sound as though its just on one cylinder or all, less than one knock per rev or more?

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Fri 10 Sep 2010 09:12
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

the knocking is in time with the engine. all cylinders. if you listen to normal sound of the engine, it is the same just much louder and clunkier. when i start the car and keep my foot on accelerator slightly to raise the speed of the tickover so to speak, there is no knocking. if i hold engine at say 1100 revs for just a couple of minutes and then take my foot off pedal and let the engine idle on it's own, the noise has pretty much gone. then let it idle for a few more minutes and the noise has completely stopped and engine sounds/runs normally.

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Fri 10 Sep 2010 10:52
Ford Mondeo diesel - knocking from engine on start up from cold - Peter.N.

Definitly sounds like over advance, do you know if the pump is electronically controlled or purely mechanical? If it is electronic I would suspect a faulty water temperature sensor. You could try disconnecting it and see if it makes any difference, should be on or near the thermostat housing.

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Mon 13 Sep 2010 15:08
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

thanks for your wise words, do you mean the fuel pump is over advancing? i'm a complete novice when it comes to cars. i will have to find a manual for it. i have looked for one before but there isn't one for my year (1998). will the one that covers mondeos up to 1996 be of any use to me? i have disconnected what looks to me like the water temperature sensor(the temp guage on the dash has dropped) so i guess that's it. will leave the car overnight now to see if it makes a difference in the morning. will let you know tomorrow. thanks again for advice.

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Mon 13 Sep 2010 16:34
Ford Mondeo diesel - knocking from engine on start up from cold - Collos25

Well it sounds like little end knock to me always on start up and disappears when warm typical symptoms.

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Wed 15 Sep 2010 11:31
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

i finally got round to leaving the car overnight at a garage. turns out the guy reckoned it was a little end knock aswell. i asked him how long would the engine hold out for and he said it could carry on as it is for a couple of years, or it could pack up next week. couldn't say for sure but advised me to give it a fresh oil and filter change.

my question is. would giving it an oil change be like flogging a dead horse? what do you guys think? also, if it is the little end/s, will the noise continue further through the rev range the closer the engine gets to its demise( giving me a bit of warning ) or will it just suddenly pack up on me driving to work one day? will be getting new car as soon as possible, but hoping it can wait until nearer the end of the year.

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Wed 15 Sep 2010 11:35
Ford Mondeo diesel - knocking from engine on start up from cold - Collos25

In my experience with an engine little end knock will last years as long as its not caned.

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Wed 15 Sep 2010 11:56
Ford Mondeo diesel - knocking from engine on start up from cold - madf

AGree with Andy.

Change the oil and filter. - possibly use a slightly "heavier" oil which will reduce the sound. When Cold . a bit.. eg if using 5/30 go to 10/30. (You want a higher number when cold - so the first number should be higher) but a maximum of 10 I would suggest or winter cold starting will be impaired..)

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Wed 22 Sep 2010 15:50
Ford Mondeo diesel - knocking from engine on start up from cold - fullyautomatix

well thanks guys for all your wise words. i have given it an oil and filter change finally, (after a full scale battle trying to get the sump plug to budge) using 10w/40. now the car does seem a lot quieter and still running fine once warm. the noise hasn't appeared to get any worse over the last week or so. so fingers crossed will keep me mobile until i get another car sorted.

thanks again.

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Wed 22 Sep 2010 19:25
Ford Mondeo diesel - knocking from engine on start up from cold - spawney

Dont think its anything to do with little ends, my old cab which i sold to another cabbie started to have exactly the same symptoms, turned out to be worn injectors. He whined like a broken vacuum cleaner about having to buy new ones but now it runs like it did when bought it at 9k, it now has 240k have a leak back test

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