Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: gareth. on 18 April 2009, 22:26:10

Title: Info on deisel 2.5 engine
Post by: gareth. on 18 April 2009, 22:26:10
Just bought a 2.5 tdi on a splate 1998, with the head gasket gone (loosing water but oil is normal). Thermostat checked.
Haynes manuals don't cover diesel models, but its a bmw engine I believe, so can I get the info from bmw to work on the engine.
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 18 April 2009, 22:28:07
It is a beemer engine, what do you want to know.

First thing, if HG failed, BMW state you cannot skim these heads...
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 18 April 2009, 22:33:29
why are they steel.
i bought the car cheap and its the same colour as my petrol omega, so i was going to change the hg and see how it goes, but even though i'm pretty handy I was hoping for a bit of info prior to me starting the job.
Do bmw use the same engine in any of their cars?
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 18 April 2009, 22:40:17
Quote
why are they steel.
i bought the car cheap and its the same colour as my petrol omega, so i was going to change the hg and see how it goes, but even though i'm pretty handy I was hoping for a bit of info prior to me starting the job.
Do bmw use the same engine in any of their cars?
beemer m51tds engine used in 325tds and 525tds. 2 varients fitted to uk omegas, earlier non maf one and later maf.


for manual...
http://images.omegaowners.com/documents/25TD/M51D25_Engine.pdf
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 18 April 2009, 22:45:33
you are good !
Excuse my ignorance but what is "maf"
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 18 April 2009, 22:49:15
Quote
you are good !
Excuse my ignorance but what is "maf"
Mass AirFlow sensor - a device that measures amount of air entering engine.

If your oil filter housing has a metal cap, its a non-maf U25DT (Vx's designation) engine, if it has a plastic cap, its a MAF X25DT (Vx's designation) engine.

Both mechanicaly identical, X25DT has a later management system, and later oil pump and filter, and a later fuel injection pump.
Title: Re: Info on deisel 2.5 engine
Post by: Andy B on 18 April 2009, 22:52:12
Quote
you are good ! ......

It's Jamie's favourite engine!!!  ::) ::) ::) :y :y :y
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 18 April 2009, 22:54:01
Quote
Quote
you are good ! ......

It's Jamie's favourite engine!!!  ::) ::) ::) :y :y :y
LOL, I bloody well think not! ;D


Saying that, I do miss my tractor  :'(
Title: Re: Info on deisel 2.5 engine
Post by: Andy B on 18 April 2009, 22:58:29
Quote
Quote
Quote
you are good ! ......

It's Jamie's favourite engine!!!  ::) ::) ::) :y :y :y
LOL, I bloody well think not! ;D


Saying that, I do miss my tractor  :'(

I don't beleieve you for a minute!  ;D ;D ;D
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 18 April 2009, 23:01:38
Quote
Quote
Quote
Quote
you are good ! ......

It's Jamie's favourite engine!!!  ::) ::) ::) :y :y :y
LOL, I bloody well think not! ;D


Saying that, I do miss my tractor  :'(

I don't beleieve you for a minute!  ;D ;D ;D
Believe me, I really do. It was a really good workhorse.  Its odd walking out on driveway, and it not being there  :'(
Title: Re: Info on deisel 2.5 engine
Post by: unlucky alf on 18 April 2009, 23:03:21
there was a guy on fleabay breaking one a while ago, said he was going to keep the head before scrapping the rest, i could try & find out if he has the head or not if you need it if ive still got his info :y
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 18 April 2009, 23:45:44
Why not, Thanks !

the link you gave me was for the beemer engine in the range rover ,i'm not well up on this engine and i'm not having the car till tomorrow to compare it. is it the same engine?
Title: Re: Info on deisel 2.5 engine
Post by: JamesV6CDX on 19 April 2009, 00:34:05
Quote
Why not, Thanks !

the link you gave me was for the beemer engine in the range rover ,i'm not well up on this engine and i'm not having the car till tomorrow to compare it. is it the same engine?

Pretty sure that's a positive...
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 19 April 2009, 07:21:41
yep same engine mate, what makes you think the headgasket is gone???
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 19 April 2009, 10:16:33
Quote
Why not, Thanks !

the link you gave me was for the beemer engine in the range rover ,i'm not well up on this engine and i'm not having the car till tomorrow to compare it. is it the same engine?
yup, range rover 2.5dse used same bmw motor
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 19 April 2009, 19:36:49
Reply to omegatoy why i think the hg is gone.

Well I havent had the motor yet, i'll probably now have it tomorrow.
so I havent driven it myself, but It is driving, and apparently loosing no power.
The garage mechanic said it could be the thermostat jammed on, but it wasn't so he said it s probably the hg.
The car is will overheat if driven a fair way and loose water, although this was watched out for and havent been fried.
The oil looks normal, no residue.
When I get hold of my mate i'll post more info.
What do you think guys?
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 19 April 2009, 21:35:26
Quote
Reply to omegatoy why i think the hg is gone.

Well I havent had the motor yet, i'll probably now have it tomorrow.
so I havent driven it myself, but It is driving, and apparently loosing no power.
The garage mechanic said it could be the thermostat jammed on, but it wasn't so he said it s probably the hg.
The car is will overheat if driven a fair way and loose water, although this was watched out for and havent been fried.
The oil looks normal, no residue.
When I get hold of my mate i'll post more info.
What do you think guys?

first job has got to be waterpump and thermostat change then flush cooling system!!!
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 19 April 2009, 21:36:30
Quote
Reply to omegatoy why i think the hg is gone.

Well I havent had the motor yet, i'll probably now have it tomorrow.
so I havent driven it myself, but It is driving, and apparently loosing no power.
The garage mechanic said it could be the thermostat jammed on, but it wasn't so he said it s probably the hg.
The car is will overheat if driven a fair way and loose water, although this was watched out for and havent been fried.
The oil looks normal, no residue.
When I get hold of my mate i'll post more info.
What do you think guys?
This sounds very familiar.

The oil jets need to be clear, and if its had poor oil servicing, these could be blocked.

If the temp has gone much beyond 110C (100C on gauge), it could cause the head to crack (common bmw problem), or at best, HG to fail.
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 19 April 2009, 22:04:33
Cheers fellas,

since talking to my mate he said the thermostat was ruled out at the garage, wether it was renewed i dont know yet.

he also said that the car looses power when a light like a thermometer comes on, but the expansion tank isn't empty?
And when you put cold water in then it goes on fine.

It has only overheated twice so I hope not too much damage has occured.

I will test it myself tomorrow, what would you do first? and could it be a hg or cracked block or even a water pump?
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 19 April 2009, 22:08:27
Quote
Cheers fellas,

since talking to my mate he said the thermostat was ruled out at the garage, wether it was renewed i dont know yet.

he also said that the car looses power when a light like a thermometer comes on, but the expansion tank isn't empty?
And when you put cold water in then it goes on fine.

It has only overheated twice so I hope not too much damage has occured.

I will test it myself tomorrow, what would you do first? and could it be a hg or cracked block or even a water pump?
oh fak....
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 19 April 2009, 22:42:50
that dont sound good     :'(
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 19 April 2009, 22:58:41
Quote
Cheers fellas,

since talking to my mate he said the thermostat was ruled out at the garage, wether it was renewed i dont know yet.

he also said that the car looses power when a light like a thermometer comes on, but the expansion tank isn't empty?
And when you put cold water in then it goes on fine.

It has only overheated twice so I hope not too much damage has occured.

I will test it myself tomorrow, what would you do first? and could it be a hg or cracked block or even a water pump?

weel dont want to get your hopes up but if the light comes on engine goes to safe mode, but you say header tank not empty, but add cold water it goes again> how can you add water if its not empty? however it does sound like the waterpump is not corculating the coolant so when it get to hot it shuts down the engine to me change the wterpump!! they have a history of the silly plastic impellor falling off :y and causing similar probs to wht you have described
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 19 April 2009, 23:30:01
but if the water pump was faulty, would you still lose water?

and the light he described was like a thermometer that u put in your mouth??????????
 
When he said it wasn't empty why is it over heating ? I will have to see that for myself tomorrow.

But it could be the shape of the bottle, and it dont look empty to him, and he is selling me the car, ha ha. even though its cheap.

Title: Re: Info on deisel 2.5 engine
Post by: Andy B on 19 April 2009, 23:33:45
Quote
but if the water pump was faulty, would you still lose water?

and the light he described was like a thermometer that u put in your mouth??????????
 
When he said it wasn't empty why is it over heating ? I will have to see that for myself tomorrow.

But it could be the shape of the bottle, and it dont look empty to him, and he is selling me the car, ha ha. even though its cheap.


cos the pump isn't circulating the coolant. eventually you're going to loose coolant because it'l loose it out of the pressure  cap cos it's too hot.
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 20 April 2009, 01:02:45
yes of course!

like I said I will get the car tomorrow, then I will see for my self, but this now sounds more likely, the water pump I mean. That is if the tank still has water in it.

I will have to wrap tissue paper around the cap to make sure thats where its coming from.
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 20 April 2009, 08:00:34
Quote
yes of course!

like I said I will get the car tomorrow, then I will see for my self, but this now sounds more likely, the water pump I mean. That is if the tank still has water in it.

I will have to wrap tissue paper around the cap to make sure thats where its coming from.
trust me, you'll know!
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 20 April 2009, 08:01:45
And as hinted earlier, do not let the temp go above 100C on gauge - that is in danger territory.

If left to just idle, does temp still go all the way up? Or is it only when using it?
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 20 April 2009, 08:17:27
not sure leaving it on idle will actually boil it? reason being you will get a thermo syphon going
(as it was before waterpumps became the norm)
 assuming the headertank is high enough, actually tho thermosyphon was only used on fourpots if i remember correctly so maybe best to inore this!!! :o
Title: Re: Info on deisel 2.5 engine
Post by: Ian_D on 20 April 2009, 12:12:27
When the pump went on my diesel (going about 70mph on the motorway) it took seconds for the temp to rise until the temp light came on, and the throttle pedal was basically switched off. :(

I pulled over STRAIGHT away and switched it off (infact I switched engine off once i got into the nearside lane, and had slowed to about 35 mph heading for the layby with brakes slammed hard on!! - lucky there wasn't any cars in the way!).  :-X

It had spat about half a litre of water out of the expansion tank too.

I got the car home, and checked the water pump.. The impeller had broken off the shaft! >:(

Without a pump, the engine would run on idle for about a minuet or so until the temperature started to rise to 1/3 way up. I didn’t want to leave it running any longer until I fitted a replacement pump, as the temp gauge is slow to respond in the Omega, and will possibly be hoter than it actually says.

Luckily for me, there doesn't seem to be any damage to the engine, and I've since done about 150 odd miles (engine has been running over 12 hrs now, and its not used any water :)) - From what I've read, normally damage occurs.
Title: Re: Info on deisel 2.5 engine
Post by: unlucky alf on 20 April 2009, 12:25:25
Quote
there was a guy on fleabay breaking one a while ago, said he was going to keep the head before scrapping the rest, i could try & find out if he has the head or not if you need it if ive still got his info :y
well i found his info & sent him a message yesterday, just hope he answers soon but will let you know if he does :y
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 20 April 2009, 12:48:27
Quote
When the pump went on my diesel (going about 70mph on the motorway) it took seconds for the temp to rise until the temp light came on, and the throttle pedal was basically switched off. :(

I pulled over STRAIGHT away and switched it off (infact I switched engine off once i got into the nearside lane, and had slowed to about 35 mph heading for the layby with brakes slammed hard on!! - lucky there wasn't any cars in the way!).  :-X

It had spat about half a litre of water out of the expansion tank too.

I got the car home, and checked the water pump.. The impeller had broken off the shaft! >:(

Without a pump, the engine would run on idle for about a minuet or so until the temperature started to rise to 1/3 way up. I didn’t want to leave it running any longer until I fitted a replacement pump, as the temp gauge is slow to respond in the Omega, and will possibly be hoter than it actually says.

Luckily for me, there doesn't seem to be any damage to the engine, and I've since done about 150 odd miles (engine has been running over 12 hrs now, and its not used any water :)) - From what I've read, normally damage occurs.
It has a 12s damper on the gauge...
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 20 April 2009, 20:04:41
thanks again, I will do some testing and let you know on Probably wednesday because tomorrow I have to strengthen the clamps that hold the ends of the handbrake cable on the rear wishbones, on my petrol omega
Title: Re: Info on deisel 2.5 engine
Post by: gareth. on 20 April 2009, 21:26:49
so ive looked at the repair manual for the new range rover, (the link I had from the boy earlier in this topic).
It said, to replace the water, you have to remove the radiator assembly.
Is this the case on the 2.5 tdi
Title: Re: Info on deisel 2.5 engine
Post by: TheBoy on 20 April 2009, 21:29:15
Quote
so ive looked at the repair manual for the new range rover, (the link I had from the boy earlier in this topic).
It said, to replace the water, you have to remove the radiator assembly.
Is this the case on the 2.5 tdi
no
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 20 April 2009, 21:58:27
viscous off, belt off(dont break the tensioner arm tho)
 undo egr pipe to give extrsa room and undo the 2 bolts holding the w,pump it wiill be tight pulling the pump out of its hole bit it wil come!! :y
Title: Re: Info on deisel 2.5 engine
Post by: Ian_D on 21 April 2009, 00:40:27
Quote
viscous off, belt off(dont break the tensioner arm tho)
 undo egr pipe to give extrsa room and undo the 2 bolts holding the w,pump it wiill be tight pulling the pump out of its hole bit it wil come!! :y
I found removing the pump fairly easy using a big block of wood (like a 2 foot piece of fence post) rested on the pump, and hitting it hard with a mallet! Keep hitting it at one side then the other to wobble it out. End of day, the pump will more than likely be scrap.

Then get ready for the rush of coolant flowing out (unless you drained the system first)  ;D

Dont need to touch EGR pipe. Or I didnt anyway.
Title: Re: Info on deisel 2.5 engine
Post by: Omegatoy on 21 April 2009, 08:03:06
know what your saying but removing the egr allows you to see what your doing if you have never done one before!! however i do know it can be done woithout it being removed, I didnt belt mine just got a small screw driver to stsart it moving then 2 hands and rocked it back and forth till it csme out!!
Omegatoy
Title: Re: Info on deisel 2.5 engine
Post by: Ian_D on 21 April 2009, 10:56:24
Quote
know what your saying but removing the egr allows you to see what your doing if you have never done one before!! however i do know it can be done woithout it being removed, I didnt belt mine just got a small screw driver to stsart it moving then 2 hands and rocked it back and forth till it csme out!!
Omegatoy

My pump wasn't going anywhere till the mallet came out! Prob just me and my luck though!  ;D