Burning smell when towing or up steep hills

Hi Everyone.

I'm hoping someone can point me in the right direction.

I have a 2005/6 Discovery 3. When I'm driving it just on normal flat roads everything is great. But I live in south Wales with big hills and do a fair bit of towing.

Whenever I tow or go up steep hills and the engine has to work harder there is a smell of burning. I cant smell it much when moving but as soon as I slow or stop it gets quite strong. It's a chemically smell.

I have replaced the battery, alternator, timing and injector belts. Had it serviced and had a carbon clean done on it in the last 5 months since buying it.

Can anyone please help me in the right direction as to what it could be? I have topped the oil up a little bit in the last 6 months. Maybe half a litre. I'm just not sure where to go with it. I dont want some garage saying it's stupid things, when I know there are so many knowledgeable people on forums like this.

Any help would be much appreciated.

Thanks!!

Rob

Common fault is sticking rear brake callipers, which would cause the issues you have.
After a drive see if the rear wheels are excessively hot.

Auto? Manual? Star-Drive?
If manual I would think clutch-plate burning/slipping under heavy load.
If Auto, then the ATF getting rather hot and the cooler isn't coping very well.
A true Disco-Person will be along in a moment I am sure @gstuart

It's an auto. Sorry forgot to say.

I dont think it's going to be brakes as it's fine when it's just normal driving. It's only when under load, going up steep hills or towing horsebox/ cars.

Thanks for replies so far.

Are you sure its not just the CAT getting hot ( more load= more heat ) you tend get a wiff of eggy sulphur stench when you stop and the fumes waft around from the rear of the car

Robgoodfield said:

Hi Everyone.

I'm hoping someone can point me in the right direction.

I have a 2005/6 Discovery 3. When I'm driving it just on normal flat roads everything is great. But I live in south Wales with big hills and do a fair bit of towing.

Whenever I tow or go up steep hills and the engine has to work harder there is a smell of burning. I cant smell it much when moving but as soon as I slow or stop it gets quite strong. It's a chemically smell.

I have replaced the battery, alternator, timing and injector belts. Had it serviced and had a carbon clean done on it in the last 5 months since buying it.

Can anyone please help me in the right direction as to what it could be? I have topped the oil up a little bit in the last 6 months. Maybe half a litre. I'm just not sure where to go with it. I dont want some garage saying it's stupid things, when I know there are so many knowledgeable people on forums like this.

Any help would be much appreciated.

Thanks!!

Rob

Click to expand...

Hi

As @DanClarke mentions ref the atf , has it been checked / replaced

Also see if ur MAP sensor is clean along with the throttle body assembly , do u know if the egrs have been blanked please

However , What was it like before the carbon clean plse, did it burn oil and what’s the mileage plse , thks,

Have u checked that u haven’t got any oil leaks anywhere , if none found u may have to get an engine compression test done, have u noticed any smoke,

Assume when u boot it doesn’t go into limp mode along with big clouds of smoke

As a side note when u replaced the belts did u replace the oil pump and rear belt , thks

Plse let us know how it goes

Not had the ATF replaced on it yet. I will be having it done within the next few weeks.

The EGR's have been deleted. I haven't check MAP or throttle sensors so I'll check them.

I didnt seem to burn any oil before carbon clean. I only had it done as I've had it done on my other cars and it's a friend who does it cheap for me so I thought it would he worth it as it's on high miles. It's currently on 192,000. This never bothered my as it's not my everyday car, it's just for the dog and towing.

There is no smoke, no bad smells from the exhaust and I can give it a boot full and its absolutely fine. It is slightly hesitant for 1/2 seconds when pulling off, but it's never gone into limp mode or anything like that. I haven't noticed any oil leak. It's always in different places on the drive and when I move it there is never any underneath. Thw only oil I have found where I didnt think it should be is some in the intercooler pipe when I took it off.

And again, I've never seen any smoke from it. Its always been clean.

I had the rear belt replaced as well, but didnt have the oil pump replaced. Is that something that should have been done with the belts?

Thanks for your help.

edge said:

Are you sure its not just the CAT getting hot ( more load= more heat ) you tend get a wiff of eggy sulphur stench when you stop and the fumes waft around from the rear of the car

Click to expand...

It seems to be coming from the front as I can smell it when the vents are on. It doesn't seem to have a burning cat smell, more of a fluid burning smell, if that makes sense.

Thanks for your reply though. It's something I will get checked.

It’s not the fuel burning heater is it? The exhaust for that is around the passenger wheel arch area, should only kick in below 5 degrees

johnlad said:

It’s not the fuel burning heater is it? The exhaust for that is around the passenger wheel arch area, should only kick in below 5 degrees

Click to expand...

I dont think it's anything to do with that. It is doing it when its above 5 degrees and its smells different to the fumes that usually come from it.

Robgoodfield said:

Not had the ATF replaced on it yet. I will be having it done within the next few weeks.

The EGR's have been deleted. I haven't check MAP or throttle sensors so I'll check them.

I didnt seem to burn any oil before carbon clean. I only had it done as I've had it done on my other cars and it's a friend who does it cheap for me so I thought it would he worth it as it's on high miles. It's currently on 192,000. This never bothered my as it's not my everyday car, it's just for the dog and towing.

There is no smoke, no bad smells from the exhaust and I can give it a boot full and its absolutely fine. It is slightly hesitant for 1/2 seconds when pulling off, but it's never gone into limp mode or anything like that. I haven't noticed any oil leak. It's always in different places on the drive and when I move it there is never any underneath. Thw only oil I have found where I didnt think it should be is some in the intercooler pipe when I took it off.

And again, I've never seen any smoke from it. Its always been clean.

I had the rear belt replaced as well, but didnt have the oil pump replaced. Is that something that should have been done with the belts?

Thanks for your help.

Click to expand...

Hi

Thks for the reply , apologises asking so many questions

That does concern me it didn’t burn any oil before the carbon clean , personally not very keen on them

Wonder if any chemicals have been left behind in the engine oil

Also thought that ref the FBH as @johnlad mentioned , good call John

Don’t think it would hurt to get a compression test done,

Have u got the sump plate refitted , just wondering if any oil leak could possibly be dripping on it

Indeed oil pump is very important , they can fail when belts have been replaced, there is an updated model that has a stronger corner

Ref the throttle body , indeed worth checking to make sure it’s not full of junk

Also the D3 forum is full of information and wouldn’t hurt to also ask there

So thinking generally , all the brakes are ok and not binding , no smoke from exhaust , wheels cool after a drive, epb not sticking

My main concern is that oil pump cover as if they fail it’s good night engine and would hate to see that for u

Know that’s not much help but if it was mine I would

Compression test
Check MAP sensor
Throttle body is clean
Diagnostic check
Get the atf oil checked , replaced

Plse let us know how u get on, many here to help but do a post on the D3 forum as someone may have seen this before

At the end of the day I feel the carbon clean is a concern if it didn’t burn oil before

Ps, @lynall , hope u don’t mind me tagging u, what do I think mate as I know ur far more knowledgeable than myself

johnlad said:

It’s not the fuel burning heater is it? The exhaust for that is around the passenger wheel arch area, should only kick in below 5 degrees

Click to expand...

Hi mate

Hope all is well

Was also thinking that , the carbon clean is concerning if it was ok before , trying to remember if u can do a compression test with electronic testers, instead of the usual removal of injectors and gauge , trying to remember

Link for the D3 forum

https://www.disco3.co.uk/forum/