Discovery smokes and apparently gets hot

Hi.

I've just got a Discovery 300TDi for towing my horse box around, but it's got a few issues I'm not comfortable with. When driving along it can throw out a grey cloud when under heavy acceleration, it seems to get a little better after a long drive but it's still there and noticeable. The smoke isn't blue or white, it's definitely grey, and black under very heavy acceleration, but mainly grey.

I don't know if it's related but the engine also seems to stutter and struggle once at about 3k rpm, but as I mainly drive below that I don't always notice it, it's just when trying to pick up speed in 3rd I get it holding back as it does.

I also notice that when on a long hill on the motorway if I bury the pedal to keep the speed up the temperature needle goes up to the red and I panic. The other day it did this on a hill on the M5, so I backed off and put the heaters on full but it still didn't drop it stayed in the red. I was just about to pull into the hard shoulder and turned the heaters off and suddenly the needle dropped quickly straight back to the middle after I did it. I also have a problem with the dials where the rev needle really fluctuates on half power, so I'm wondering if it's probably instruments? It never does this around town just on the motorway if you really plant the pedal!

I'm really worried because it's my brothers car he just lets me use it for towing my horse box because I've only got a Focus! He says that the engine is a little tired which is why it smokes but it should be okay for now until he changes it with a recon engine. He also thinks that the temperature needle is an instrument problem but I'm not so confident?

He also said the diesel pump has been tinkered with which is why it smokes a bit, which I believe because until 3k it goes better than a friends 300tdi I borrowed before, Im just worried about whether I should use it for towing my horse box the way it is in case I ruin it. I have to add that he towed my friends horse box with it the other day and he said it was fine as long as he went gentle, but I still want some more opinions.

Can anyone give some opinions on the matter please

H x

Most obvious solution is to check the condition of the radiator and check that it has all it's fins. I only noticed that my 200 was missing the bottom half of it's rad fins when it got hot towing in August a couple of years back....the TDi is a little over cooled.

However, the IP tweaks will increase the EGT (exhaust gas temperture) which is having a knock on effect into the coolant temperature. This can be eleviated if a larger intercooler has been fitted which will reduced the induction air temperature and have a cooling effect. I would also check and see if one of these has been fitted as well.

First thing tho', check the condition of the radiator. Do this soon or else you could blow the head gasket and even warp the head itself.

Hope this helps.

If it's your brothers car and he's happy then why worry....
If it was mine I would worry though...
The over heating could be many things...blocked radiator or faulty thermostat are two candidates.
The rev counter all over the place could be a loose connection...thin white wire on the back of the alternator.
The smoke could be due to the fuel pump tweeks and the engine being "tired", but again it could be other things...cleverer people than me will suggest some soon I'm sure

The smoke you describe could be oil getting into the cylinder, it could be via worn rings or valve seals etc... The tinkered injection pump would cause black smoke more than likely so I would rule out injection problems.

I recently had a bad case of grey smoke under acceleration (like enough to smoke out a road) I took the head off and rebuilt it, it was leaking valve stem seals, causing the smoke in my case, I also had badly seating valves and things too though. Seals can be done without taking the head off and are not expensive. It might be injectors, might be worth getting these checked out, worth starting with the cheapest first. Does it smoke at idle?

The overheating problem, I disagree that it is an instrument problem, from what you have told me it does coincide with you working her a little harder, also since you said it suddenly dropped that sounds like a jammed or late opening thermostat to me. £3 for a new one, two bolts to fix it, you could do it and not even tell him. You will also need a bit of coolant to top up the system, don't use just water as it's heading into the winter now.

Damn it! I should read the whole post and not just skim!!

Hannah said:

I was just about to pull into the hard shoulder and turned the heaters off and suddenly the needle dropped quickly straight back to the middle after I did it.

<snip>

He also thinks that the temperature needle is an instrument problem but I'm not so confident?

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I agree that this does sound like a sticking thermostat and is unlikely to be a instument problem.

Im just worried about whether I should use it for towing my horse box,

poor horse, it must get some of the smoke in the horse box

it sounds like the pump has been tweaked too much and needs to be backed off a bit! as ANDYB66 says your egt is probably too high and it wont be long before the engine goes into meltdown. there are a few posts on here about how to tweak the pump and how to do it safely but it looks like a case of trying to squeeze a bit more power and going a bit too far.

If this was my vehicle the first thing I would think is, is it getting enough fresh air? So I would bin the air filter and put a shiny new one in.

Next, on the overheating front, I would be changing the thermostat, checking the viscous fan and flushing out the rad. I would also check the functioning of the water pump.

Thanks for all the replies peeps!

The reason it bothers me is because I don't want to get stuck on the side of the road with a broken car lol

I'll have a wee look at the radiator and see if I can change the thermostat with a haynes manual and borrow my brother's tools too.

Someone asked if it smoked much on idle, well it does if it is cold, you can see puffs of grey smoke but it's not too bad. It's clear after a while though at idle, just smokes alot on full power!

The exhaust temperatures out the back are well hot though so if you put your hand by the exhaust after it's been running for a few minutes its too hot to keep your hand there. Much hotter than my focus petrol exhaust gases, but I don't know about diesels?!!

I was told by my neighbour who is an MOT tester that if the exhaust cloud is blue it is valve seals or piston rings, but is that blue and grey or just blue Im confused?

Horse won't get any smoke in the box because the ventilation points are at the back of the box

Thankyou!!!!!!!!!!!!

H x

Grey or black smoke is unburnt fuel, blue smoke is burnt oil

sounds to me the pump has been tweaked too much in relation to other things like airflow and exhaust restriction. If the EGT is too high on full power the engine will get very hot and can possibly melt pistons and turbos

As well as all the advice other people have given I would definitely check the injector pump settings, the air filter and the exhaust cat for blockages

HTH

Dave

Hi Dave

I think hes already removed the cat.

How would I turn the pump down and then back so he didn't notice?

H x

It's pretty easy, look on the pump - as you stand next to the driver's wing, you'll find two long screws on the side nearest you. you want the one with a 6mm hex on the end and a 13mm nut locking it (the other's for the idle speed and has a 10mm nut loking it), slacken the nut and turn the screw quater to half a turn anti-clockwise (iirc, whichever direction slows the idle down) then hold the screw and nip the 13mm nut up but don't go mad as it's not easy to get at and you may have trouble putting it back to how it was! Oh, don't forget how much you turned it!!

You'll find it has less power but smokes less and possibly stays cooler.

To my mind though, what you've described is normal - any engine with a turbo will get hot when the turbo's running a lot (like lugging a horse up a long hill) and will smoke more than usual because of the load. I'd replace the air filter (only a couple of quid) and have a look at the radiator (and check the coolant level) but I wouldn't worry too much to be honest, I've had no end of lorrys do the same to me, the temp goes down pretty quick on the way back down the hill.

The most important thing to remember is if it gets to the red mark STOP! let the engine idle, open the bonnet and stay put until it's cooled down.

Thin_trucker said:

It's pretty easy, look on the pump - as you stand next to the driver's wing, you'll find two long screws on the side nearest you. you want the one with a 6mm hex on the end and a 13mm nut locking it (the other's for the idle speed and has a 10mm nut loking it), slacken the nut and turn the screw quater to half a turn anti-clockwise (iirc, whichever direction slows the idle down) then hold the screw and nip the 13mm nut up but don't go mad as it's not easy to get at and you may have trouble putting it back to how it was! Oh, don't forget how much you turned it!!

You'll find it has less power but smokes less and possibly stays cooler.

To my mind though, what you've described is normal - any engine with a turbo will get hot when the turbo's running a lot (like lugging a horse up a long hill) and will smoke more than usual because of the load. I'd replace the air filter (only a couple of quid) and have a look at the radiator (and check the coolant level) but I wouldn't worry too much to be honest, I've had no end of lorrys do the same to me, the temp goes down pretty quick on the way back down the hill.

The most important thing to remember is if it gets to the red mark STOP! let the engine idle, open the bonnet and stay put until it's cooled down.

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Ok but that will only adjust off-boost fueling, seeing as its smoking on boost its probably the diaphragm that needs turning back a bit and if you are not sure what you are doing its best not to as it entails taking the top of the pump off

edit sorry just reread your post, you are talking about the main fuel screw right? this ussually has a seal on it anyway

If the fuel pump has been tweeked then its unlikely to be by the method described above. As ccrdave says, it is more likely to have involved taking the cover off the pump and moving the diaphragm and may be more.
You are driving a Disco, not a lorry, it is not normal for the temp gauge to go up as you described. You need to check the outside of the radiator for missing fins and mud/leaves. You need remove the mounting bolts from the top to tilt it back to see the front...but it may be the inside that is bunged up. back flushing it may help, or you may need a new rad. As said before, its also worth checking the thermostat.
I would strongly advise against doing the fuel pump adjustments that thin trucker recommends..you could end up in a right mess

i tweaked the pump on my disco with no problems but if it has been overdone and it has not been noted where the original settings are it would be near impossible to go back to standard settings without the use of specialised tools.

Hannah said:

Someone asked if it smoked much on idle, well it does if it is cold, you can see puffs of grey smoke but it's not too bad. It's clear after a while though at idle, just smokes alot on full power!

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Right - I think now we are are getting a fuller picture, the grey smoke on idle is probably not related to the overheating/full load smoke but simply it is a tired engine. The idle smoke is probably oil in your case. Leaking down past the valve stem seals when the engine is off, it builds up in the inlet valve and it acts like a fuel for a while, it doesn't burn blue like oil would usually and this is due to the way it is coming into the cylinder almost as a mist - this could also be adding to the smoke when driving hard. The LR TDI's do this quite often when valve leaks occur.

There is a fairly easy way for you to check this: take the inlet manifold off, not a big deal, 4 bolts and the pipe from the intercooler, look into the ports, can you see lots of oil in any of them? But if he has a recon engine planned you probably would not bother.

ccrdave said:

Grey or black smoke is unburnt fuel, blue smoke is burnt oil

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Not always - for the most part you can apply this logic but there are times where an engine will throw you in the wrong direction.

The pump has been horsed with by somone who doesn't understand what is going on by the sounds of things. Backing it off would take care of this probably. But I am beginning to think it could be all sorts leading to a poorly running
engine.

Not the same pump, but the bits you want to work with are the same: http://dodgeram.org/tech/dsl/more_power/Power_ve.htm


The sudden dropping in engine temp is almost definatly stat related as backing off would not cause it to drop temp that quickly, the engine is a BIG lump of metal - it needs some serious water flow to cool it.

I think we are all getting a bit too excited

The cooling of this engine is obviously at fault in some way. The state/condition/operation of the thermostat, water pump and radiator should be checked. Let's make sure that the simple things are right first.

Yes I know I also mentioned fuelling, but I'm pretty sure I said check the condition of the radiator first

Thanks alot peeps!

I had a quick look at the radiator and it seems to be fine all the layers are there and the fan works fine too. The car has air conditioning though so there is a big radiator infront of it I cant get in to see if it is blocking the airflow. I asked my brother if hed change the thermostat and he said he would if he could find one soon enough, if not he would remove the thermostat until he did?

I sweet talked him into turning the pump down a bit

Hannah said:

Thanks alot peeps!

I had a quick look at the radiator....The car has air conditioning though so there is a big radiator infront of it I cant get in to see if it is blocking the airflow. I asked my brother if hed change the thermostat and he said he would if he could find one soon enough, if not he would remove the thermostat until he did?

I sweet talked him into turning the pump down a bit

Click to expand...

You have to start taking the radiator out, there is a bracket across the top, you can release that and tilt it back to see the front side of the radiator...mine was full of leaves and mud....

Let us know how you get on

^^^ What Richard said about radiator check. Also would not run engine without a thermostat. It's a bodge and can cause other problems.