Diesels in winter - cold outside and inside
Discussion
I drive a Skoda Octavia with the 1.6l diesel engine with 105hp.
( Mods : Please leave this here as it may not be a specific Skoda topic. )
My daily drive to work is about 8 miles in the city, takes about 25 minutes.
I had never driven a diesel regularly before (company car),
and have noticed that the heating in this distance seems to be non-existent.
After 4 miles the water temp sohws about 50° and after 6 miles it rises to 90°,
but even then the air coming out of the heating seems to be only 20°.
Is this due to the modern "temperature efficiency" of diesel engines ?
I remember my petrol-fuelled Opel and VW as getting warmer quite quickly.
Is there any trick that could improve the heating output ?
I thought of covering up (parts of) the radiator but maybe this sets off ECU alarms ?
( Mods : Please leave this here as it may not be a specific Skoda topic. )
My daily drive to work is about 8 miles in the city, takes about 25 minutes.
I had never driven a diesel regularly before (company car),
and have noticed that the heating in this distance seems to be non-existent.
After 4 miles the water temp sohws about 50° and after 6 miles it rises to 90°,
but even then the air coming out of the heating seems to be only 20°.
Is this due to the modern "temperature efficiency" of diesel engines ?
I remember my petrol-fuelled Opel and VW as getting warmer quite quickly.
Is there any trick that could improve the heating output ?
I thought of covering up (parts of) the radiator but maybe this sets off ECU alarms ?
Diesels certainly don't warm up as quickly as petrol engines, but if your heater is still cold when the coolant is at 90, which I would expect to be around it's normal operating temperature, it seems your problem probably lies elsewhere. Does it have climate control or manual heater controls? I know of an issue that affects VAG cars where a motor in the heater system itself stops working. This has happened to 2 friends of mine, one in a fabia vrs and the other is an 03 polo. Reading the fault codes will reveal if this is the problem.
I don't think you'd achieve much by covering up the radiator. I would have thought the heater matrix was on the other side of the thermostat to the radiator, so it would be warm before the radiator. But I could be wrong.
I don't think you'd achieve much by covering up the radiator. I would have thought the heater matrix was on the other side of the thermostat to the radiator, so it would be warm before the radiator. But I could be wrong.
Car engines, whether petrol or diseasel will take longer to warm up if you have the heater on, purely because an amount of heat is being extracted from the cooling system.
Diesels can take longer to warm up because they are heavier duty engines - and parts like the block take longer for heat to soak them.
If you have no heat in your.. erm.. heater then you most likely have an airlock in the system. This isn't a disaster (I have quite a nice one in my diesel VW Bora, thanks to a head gasket issue) but to solve, you need to run the car either with the expansion cap off, or if there's a bleed point, with that open until water/coolant starts dribbling out of it.
Diesels can take longer to warm up because they are heavier duty engines - and parts like the block take longer for heat to soak them.
If you have no heat in your.. erm.. heater then you most likely have an airlock in the system. This isn't a disaster (I have quite a nice one in my diesel VW Bora, thanks to a head gasket issue) but to solve, you need to run the car either with the expansion cap off, or if there's a bleed point, with that open until water/coolant starts dribbling out of it.
I've got a fuel burning heater on the MG ZT-T. It's a small unit that sits in the engine bay and is plumbed into the coolant system. It has a mini water-pump and fuel pump that feeds it. If the outside temperature is less than 5 degrees when the engine is running it will kick in to warm up the coolant quickly.
The next step is to fit a remote control so I can start the heater in the mornings to save scraping the ice off
I know that VAG and BMW had options of fuel burning heaters. You could always see if it was an option on the Octavia and get one from a scrappy. That's what I did on the MG. All the fuel lines and wiring looms were in place, so it was pretty straight forward to fit.
The next step is to fit a remote control so I can start the heater in the mornings to save scraping the ice off
I know that VAG and BMW had options of fuel burning heaters. You could always see if it was an option on the Octavia and get one from a scrappy. That's what I did on the MG. All the fuel lines and wiring looms were in place, so it was pretty straight forward to fit.
The engine is diesel and yes the heater unit is definitely fuel fed. The heater has a mini glow plug that burns the diesel to create the heat. There is a small air intake and exhaust. The diesel engine in the ZT is BMW unit. Because the engine was very thermally efficient they added the fuel burning heater.
As mentioned they were also fitted to some VAG cars and BMW's, I'm pretty sure Merc used them too. As far as I know all the units are actually made by Webasto. A search for Webasto Thermotop will bring up more technical details on how they work.
Cool bit of kit though, well hot....but you get what I mean
As mentioned they were also fitted to some VAG cars and BMW's, I'm pretty sure Merc used them too. As far as I know all the units are actually made by Webasto. A search for Webasto Thermotop will bring up more technical details on how they work.
Cool bit of kit though, well hot....but you get what I mean
MatthewO said:
Car engines, whether petrol or diseasel will take longer to warm up if you have the heater on, purely because an amount of heat is being extracted from the cooling system.
Diesels can take longer to warm up because they are heavier duty engines - and parts like the block take longer for heat to soak them.
Diesels are more efficient, so less energy is wasted, therefore less heat. I would say there is a problem, its not even that cold yet, Diesels can take longer to warm up because they are heavier duty engines - and parts like the block take longer for heat to soak them.
If it was minus all the time I would understand. Car should be warm within 5 miles
though ours needs a service as its not 100% 
Fitted to a lot of Saab 9-3 2.2 Diesels too. Don't panic if you see smoke coming out from under the car around the front doors; that's just the exhaust for it.
OP if the gauge reads hot and it appears to operate correctly, you either have air in the heater matrix or a build up of sludge. Something is preventing the hot water from the engine from flowing to or through the heater matrix, or a flap in the heater itself is preventing hot air to flow out.
What's the age/ mileage of the car?
OP if the gauge reads hot and it appears to operate correctly, you either have air in the heater matrix or a build up of sludge. Something is preventing the hot water from the engine from flowing to or through the heater matrix, or a flap in the heater itself is preventing hot air to flow out.
What's the age/ mileage of the car?
GTIR said:
Blimey.
So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Yup the Jaguar S-Type had a Webasto type heater as well, tripped in at 5 Deg C. & below. One of the things I hated about very high tech diesels is the time it takes for the heater to do anything useful!So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
tr7v8 said:
GTIR said:
Blimey.
So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Yup the Jaguar S-Type had a Webasto type heater as well, tripped in at 5 Deg C. & below. One of the things I hated about very high tech diesels is the time it takes for the heater to do anything useful!So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Very handy to get the engine warm quickly and get the car warm.
Standard fittment on all LR cars that go to cold climates.
Only issue with them is they can clog up if not run so stop working until a dealer or Indy gets it to purge and clean itself out.
My freebys worked great, the disco3 is needing an Indy to get it working.
A.J.M said:
tr7v8 said:
GTIR said:
Blimey.
So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Yup the Jaguar S-Type had a Webasto type heater as well, tripped in at 5 Deg C. & below. One of the things I hated about very high tech diesels is the time it takes for the heater to do anything useful!So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Very handy to get the engine warm quickly and get the car warm.
Standard fittment on all LR cars that go to cold climates.
Only issue with them is they can clog up if not run so stop working until a dealer or Indy gets it to purge and clean itself out.
My freebys worked great, the disco3 is needing an Indy to get it working.
mrmr96 said:
A.J.M said:
tr7v8 said:
GTIR said:
Blimey.
So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Yup the Jaguar S-Type had a Webasto type heater as well, tripped in at 5 Deg C. & below. One of the things I hated about very high tech diesels is the time it takes for the heater to do anything useful!So it's got a mini engine in the engine?
Assuming your car is petrol (or diesel) isn't that a bit OTT?
Are you sure it's not an electric heater rather than a complicated fuel burner?
So many questions.
Very handy to get the engine warm quickly and get the car warm.
Standard fittment on all LR cars that go to cold climates.
Only issue with them is they can clog up if not run so stop working until a dealer or Indy gets it to purge and clean itself out.
My freebys worked great, the disco3 is needing an Indy to get it working.
It's like the cab heaters in trucks which work off the diesel but are quite noisy, and expensive.
I can sleep now.
Related. My Merc had a "rest" function that blows hot air out for 30 mins once you've turned off the (hot) engine. Quite handy in winter and hanging around.
Skoda’s can have fuel powered auxiliary heaters but they probably don’t fit them on UK cars - few manufacturers offer them in the UK these days.
They also fit ceramic heaters to the cabin air flow in some markets – but not in the UK, apparently. I drove a Merc with those last winter and it was weird – warm air comes out instantly, like turning a hair dryer on!
However there’s usually some form of heater booster – a small, efficient diesel would take ages to warm up without one. A lot of cars have an electric heater in the coolant but take so much current they usually only work when the car is moving. My Merc has one of those but it only works below 8C. It can be turned on and off using the a/c button so some people think the a/c pump is warming the car up. Actually Honda do that – use the a/c compressor in reverse as a heat pump.
They also fit ceramic heaters to the cabin air flow in some markets – but not in the UK, apparently. I drove a Merc with those last winter and it was weird – warm air comes out instantly, like turning a hair dryer on!
However there’s usually some form of heater booster – a small, efficient diesel would take ages to warm up without one. A lot of cars have an electric heater in the coolant but take so much current they usually only work when the car is moving. My Merc has one of those but it only works below 8C. It can be turned on and off using the a/c button so some people think the a/c pump is warming the car up. Actually Honda do that – use the a/c compressor in reverse as a heat pump.
Benni said:
After 4 miles the water temp sohws about 50° and after 6 miles it rises to 90°,
but even then the air coming out of the heating seems to be only 20°.
If the engine is geeting up to temp (6 miles sounds fine) but the heater output is still crap then that suggests a problem with the heater. but even then the air coming out of the heating seems to be only 20°.
I don't know how it works on VAG cars - is there a water valve, or does it just mix air?
Does the car have digital climate control or twiddly knobs? Try it set on re-circulation.
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