External pad-type of sump heater on a TDi - Is there a suitable mounting location on the sump?

[dj_efk]

As per my blog, I’ve been looking into engine pre-heating for Merlin and have bought a Calix coolant heater kit.

This does not heat up the oil however, hence I wondered whether a separate heater attached to the sump would further shorten the long warm-up time of the TDi (my car is an ATL 90 version). The aim is to have petrol-like heated air available for demisting and heating within moments of starting, then a similar engine warm-up time to operating temperature, thanks to 60-90 minutes or so of pre-heating before the first start of the day; something that I understand can take a long time on a diesel A2 - This would literally cost pence in electricity yet save fuel and on engine wear - the latter is important as I want to keep Merlin running many more 100ks of miles.

I’ve found a brand with a good reputation for safety (there are a lot of generic Chinese ones out there with no thermostat control or earth wiring!) and the only requirement for them to work safely is that they must be mounted on a flat part of the sump (it doesn’t matter where as aluminium is such a good thermal conductor), plus of course it cannot be mounted right next to the plastic under tray.

For reference, I was thinking of one this shape (15x4cm) ....

Or perhaps this shape (8cm, round):

Here’s the full range of these, for interest: https://www.t7design.co.uk/engine-heating/phillips-temro-industries.html?cat=106&voltage=6103

My plan was to somehow incorporate the wiring for this into the on-board inlet wiring for the Calix, hence both would operate together. The 125w model is sufficient for this application (up to 4.5l of oil being heated).


My question is, can anyone with a diesel A2 suggest a good place to mount one with this in mind? They are pretty small in size as below.

Those of you who know me will know I’m overseas / not near my A2 at present and hence can’t look under my car for myself!

 

[mrbroons]

Just from my experience with my TDI 90 it heats up very quickly and I’m starting to get warm air and de mist within 2 minutes, certainly long before any comparable petrol or larger diesel I’ve owned.

I get the heating the oil, as the motor being up to temp is an issue but the electric heater or webasto on older TDI is very effective in my experience for cabin heat.

James.


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[Guest 4123]

Just from my experience with my TDI 90 it heats up very quickly and I’m starting to get warm air and de mist within 2 minutes, certainly long before any comparable petrol or larger diesel I’ve owned.

Isn't that because you have an electric cabin heater? If you don't have such an electric cabin heater, an A2 can take a long time to warm up, especially if it's a diesel. Try it - press ECON!

An A2 with just hot oil will take a lot longer to heat up than an A2 with a coolant heater, especially one with a pump.

RAB

 

[dj_efk]

@mrbroons James, you are of course correct that the cabin heat element is already covered, however does the electric element on the later A2s only kick in at really low temps? I'm pretty sure I've read elsewhere on the forum that this is the case with the Webasto - and anyway, cold oil won't flow as well and the TDI makes a racket and uses more fuel when cold, so anything that can be done to shorten the warm-up to full operating temperature is a bonus.

I guess I'm thinking about those "cold but not freezing" morning starts with this.

I've now edited the subject of the thread so it's clear what I'm asking.

 

[nod]

have a read of this thread, might be a better way to go?...coolant heater

Eco Alan

I’ve decided to start the story of my A2 - nicknamed Alan. It’s not really a project car, but my quest to improve its economy and the fact it’s getting under my skin (most of you will know that feeling towards your A2s!) means I am gently tinkering with it. Despite only being bought as cheap...

www.a2oc.net

 

[dj_efk]

have a read of this thread, might be a better way to go?...coolant heater

Eco Alan

I’ve decided to start the story of my A2 - nicknamed Alan. It’s not really a project car, but my quest to improve its economy and the fact it’s getting under my skin (most of you will know that feeling towards your A2s!) means I am gently tinkering with it. Despite only being bought as cheap...

www.a2oc.net

You'll see from Merlin's blog that Ian's thread has been an inspiration to get a Calix version of that heater. I'm now thinking that pre-heating the engine's oil simultaneously would help reduce the warm-up time (and cold engine wear / noise!) further.

It's now cheap to add this as an additional item to the setup I've bought if I can plumb in to the Calix on-board wiring loom, they do a splitter and I'm sure I can buy an additional cable to modify that would connect to the pan heater.

 

[Jellybean]

From experience with industrial diesels expected to start at low ambient temperatures the sump heater pads are not very effective. I tried them many years ago during testing and gave up. If you really want to heat the sump oil then get z boss welded on a face of the sump, drill & tap, and fit an immersion heater. This will effectively warm the whole engine.
For an A2, the coolant heater option is by far the most effective way to preheat, although correct plumbing will play a part in this. For maximum effect you need to heat the whole of the coolant, including that in the radiator.

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[dj_efk]

From experience with industrial diesels expected to start at low ambient temperatures the sump heater pads are not very effective. I tried them many years ago during testing and gave up. If you really want to heat the sump oil then get z boss welded on a face of the sump, drill & tap, and fit an immersion heater. This will effectively warm the whole engine.
For an A2, the coolant heater option is by far the most effective way to preheat, although correct plumbing will play a part in this. For maximum effect you need to heat the whole of the coolant, including that in the radiator.

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Thanks for the benefit of your experience. Perhaps while the sump is off for the balance shaft chain and sprocket replacement I should consider this - as I doubt the labour would be much additional.

Calix do such an immersion heater - And this way there'd be no need to b*****dise their wiring / cable AND there'd be no risk of melting the plastic undertray......

Hmmmm.

 

[dj_efk]

Carrying on from above - Can anyone confirm all the diesel sumps are the same? This is a TDI 75 / AMF sump apparently.

If so, it does look like an immersion element could be a good idea.

 

[mrbroons]

Isn't that because you have an electric cabin heater? If you don't have such an electric cabin heater, an A2 can take a long time to warm up, especially if it's a diesel. Try it - press ECON!

An A2 with just hot oil will take a lot longer to heat up than an A2 with a coolant heater, especially one with a pump.

RAB

All A2 TDi's AFAIK have an Webasto or Electric cabin heater to resolve just such an issue. If you choose not to use it then indeed it will take ages but why would you?

@dj_efk - totally agree that reducing emissions and warm up time (aside from cabin temp) is a different matter, but not sure how effective any trivial solution would be on this vs the hassle of installation and electric hookup to feed in power. Not sure if you have this option but would a sealed and heated garage not achieve the same thing (and a lovely place to cocoon the car also) during the Winter?

Also I believe diesels lose their heat relatively quickly when not under load, if heating is the objective I presume your travel would involve being under decent load for the rest of your journey or the effects may be lost relatively quickly. I am however NO expert!

J

 

[audifan]

It may be an easier route to either modify the electric auxiliary heater operating temperature with an over ride switch, or even the fitting of a second electric heater into the air box. Perhaps next to the pollen filter location. Yes I believe the bottom ends are the same in the 1.4 diesels.

 

[Guest 4123]

All A2 TDi's AFAIK have an Webasto or Electric cabin heater to resolve just such an issue. If you choose not to use it then indeed it will take ages but why would you?

I didn't say that I choose not to use it but was explaining why your A2 cabin heater heats up your cabin so quickly. The OP wants his engine preheated which an electric cabin heater won't do.

RAB

 

[audifan]

Agreed but OP also states " The aim is to have petrol-like heated air available for demising and heating within moments of starting, then a similar warm-up time to operating temperature, thanks to 60-90 minutes or so of pre-heating before the first start of the day" Just trying to provide another way of the quicker hot air. Engine heating through the coolant and or the oil would still be needed to get the engine up to temperature quicker. Is there an external electric blanket / insulation that can be used?

 

[Guest 4123]

Agreed but OP also states " The aim is to have petrol-like heated air available for demising and heating within moments of starting, then a similar warm-up time to operating temperature, thanks to 60-90 minutes or so of pre-heating before the first start of the day" Just trying to provide another way of the quicker hot air. Engine heating through the coolant and or the oil would still be needed to get the engine up to temperature quicker. Is there an external electric blanket / insulation that can be used?

As he has Td90, he already has the electric cabin heater option so he's either not using it or it's broken. The electric cabin heater will have absolutely no effect on warming up the engine.

RAB

 

[gills]

You've got me thinking about this! The water heater is plumped in just below the oil cooler at the bottom of the oil filter housing, so it should mean that the oil in the filter, at least, gets warmed. I will have to plug my OBDeleven in to see what the oil temp is like from a cold start, with and without running the water heater.

 

[dj_efk]

As he has Td90, he already has the electric cabin heater option so he's either not using it or it's broken. The electric cabin heater will have absolutely no effect on warming up the engine.

RAB

@RAB - you may not know, but I’ve never even seen my car in the metal - indeed, I’ve never even seen an A2 up close. So you’ll need to make allowances for / point this out if it’s warranted.

I have a lot of free time (and some cash) to spend working this stuff out

 

[audifan]

While I can understand what is trying to be achieved here. You can get to a point where cost spend does not equate to gain achieved. If the car was permanently in a cold and icy location then it is far easier to justify costs. In the UK especially the south east which generally has the mildest climate those costs become harder to justify and have to be looked at on a personal satisfaction basis. If the car is used and parked away from home then the ability to plug it in may not be there. I am pretty sure the tdi 90 has the higher power auxiliary electric heater that really is good. The best solution in the UK is to garage the car overnight then it is only the return journey where you may have to worry about the temperature. I know not everybody has a garage they can use. I remember my dad placing an old blanket over the engine when he parked at night to retain more heat and me removing it in the morning before he took me to school.

 

[Guest 4123]

@RAB - you may not know, but I’ve never even seen my car in the metal - indeed, I’ve never even seen an A2 up close. So you’ll need to make allowances for / point this out if it’s warranted.

If you've never seen it, how do you know that you've not already got a pre-heater? Unlikely maybe but..... I would recommend some time reading the manual (if you've got one)!

RAB

 

[mrbroons]

I didn't say that I choose not to use it but was explaining why your A2 cabin heater heats up your cabin so quickly. The OP wants his engine preheated which an electric cabin heater won't do.

RAB

Totally agree RAB as per my prev post. ?

 

[audifan]

In reality the electric auxiliary heater does help warm up the engine quicker but only slightly. This is due to the positioning of the electric heater below the heater matrix in the cabin. The air is blown by the fan into the cabin and also rises into the matrix putting some warmth into the coolant system however marginal.