Engine Preheater on 2.25 diesel

[Series 1 2 & 3]

I've fitted an engine preheater on my newly installed rebuilt 2.25 diesel engine.

The reason being that winter is approaching (and I am getting old) so I want to minimise the discomfort and inconvenience on those cold/wet/damp/freezing mornings that are so common around here in the Fens.

I've never used a preheater before although I have often thought about fitting one but been put off with the faff, disturbance and expense.


After a lot of thought I decided to keep everything cheap and simple if I could.

This is what I bought:

https://www.ebay.co.uk/itm/3KW-220V...767823&hash=item590890fcd1:g:pSEAAOSwLXtal82y

It was only £24.88 and arrived within 10 days.
I didn't think much of the flimsy mounting bracket supplied with it nor the undersize tee pieces so I did not use them.
The actual 3 kilowatt preheater looked quite well built.

I mounted it to the spare left-hand drive steering column mount near the starter motor using 2 set screws and packing washers.
(see photos)
I used an existing hole in the mount and drilled an additional hole for the other set screw.

I cut off the European plug on the mains flex and threaded it into a short piece of flexible conduit for added protection.
I fed it through the dash bulkhead into the dashboard tray and fitted a 13 amp plug.
The flex was just long enough.
I intend to use an extension lead to supply the plug in the cab and probably thread the lead through the steering wheel so I won't drive off and forget it!

After looking at the high prices of 16mm metal tee pieces online I decided I'd make up the pipework myself using 15mm copper pipe and yorkshire fittings from my stock in the shed.

For the flow from the preheater I removed the heater tap from the thermostat housing and used a spare brass hose connection in its place.
I made up the pipework using 2 copper tee pieces and short pieces of pipe.
I also fitted a bleed valve to let out any trapped air.
To make absolutely sure that the rubber hoses would not slip off the plain copper pipe I also soldered onto them straight connections or straight connections cut in half (depending on the amount of space I had to play with).
The raised ring on the yorkshire fittings give extra grip.
I connected the pipework to the top of the preheater using 16mm rubber pipe.

For the return to the preheater I used 1 copper tee piece and short pieces of pipe and installed it in the return pipe of the cab heater.
I used 16mm rubber pipe and a 180 degree bend to connect up to the bottom of the preheater.

I topped up the cooling system, checked for leaks then took the vehicle for a run to clear out any air that may be trapped in the system before switching on the preheater.

The following morning (today) I switched on the preheater.
There was a slight whirr from the inbuilt water pump telling me something was happening.
After 5 minutes the pipework was warm.
After 15 minutes the cylinder head was warm to the touch.
At 25 minutes the preheater switched itself off and the engine was almost up to normal temperature.
(see photo)
Although today is not that cold (about 11 degrees C at lunchtime) I am impressed with how well it works.
I'm almost looking forward to the cold weather later on this week!

 

[paul123]

Its good to see how well these heaters work . I have 2 of them I am trying to get time to fit 200tdi range rover and 300tdi disco .

 

[DarrenH]

thats pretty neat, will need a bit of planning i guess to switch it on? 3kw might be a bit above the ability of normal timer switches

 

[Big Sandy]

It will be nice for you to have a warm cab and demisters as soon as you get in it this winter!

 

[Big Sandy]

thats pretty neat, will need a bit of planning i guess to switch it on? 3kw might be a bit above the ability of normal timer switches

Plug it in the night before, switch it on when you get up in the morning half an hour before going out. Which is okay if you can leave the cable lying outside.

A caravan socket, maybe one that folds down on itself flush with bodywork, might be a neat option too, like the hookup extensions they use on camp sites.

 

[Truckcab79]

Nicely done. Takes away all the fun of freezing to death and driving half-blind until minutes before you actually arrive at your destination though.

 

[Series 1 2 & 3]

Nicely done. Takes away all the fun of freezing to death and driving half-blind until minutes before you actually arrive at your destination though.

I couldn't have put it better myself.

Thanks for all of the comments.
Yesterday I took an inordinate amount of time wiring up a waterproof outside socket near to where I park up.
Only AFTER I had fitted and wired in 3 armoured cable water-proof connectors to the plastic back box and screwed everything in place did I notice the word TOP upside down on the bottom of the plastic back.
DOH!
Why the manufacturer should produce a plastic back box that is, to all intents and purposes, symmetrical in appearance and shape except for where the front screws to the back by about 4mm difference I'll never know.
And why do they make the plastic boxes so flimsy when they have to accept heavy and stiff armoured cable attached to them?

Anyway I tested it out today ( @ 4 degrees C. ) and went for a drive.
I gave the preheater about 25 minutes to warm up the engine.
It worked well.
Although the heater in the station wagon has never been "toasty" I didn't spent the first few miles wondering where all the draughts were coming from.
The windscreen cleared quickly too.
Of course the new engine's bearings etc. are still stiff when cold (its only done about 150 miles) and the preheater doesn't warm them up so it still takes a lot of effort for the starter motor to turn the engine.
On the second spin of the starter it starts almost immediately.

The preheater is definitely an improvement.
I might be tempted to fit an additional heater in the back of the station wagon now.

 

[paul123]

a quick question about the plumbing one connection is in the head to heater pipe where does the other go ?

 

[Series 1 2 & 3]

a quick question about the plumbing one connection is in the head to heater pipe where does the other go ?

Sorry, neither my description nor the photos make it very clear.
The connection you refer to is partly obscured by the large flexible air intake pipe and the butterfly valve section of the manifold.
A rubber pipe runs from the top of the preheater forward over the manifold to a copper pipe coming from the pipework where the heater tap used to be.




If you look carefully at the picture of that pipework you can see a pipe running across the top of the rocker cover and also just see a hose clip where the rubber and copper pipes join directly under the flexible pipe.
It is not obvious but there are 2 tee pieces in the pipework.


Effectively the cab heater and cylinder block are fed with heated coolant in parallel with one another.

This is the recommended way of fitting the preheater.

 

[Extreedoc]

Always wanted one of those, thought they were too expensive and difficult to source. That one of yours at that price make it all worth a punt. I could switch over to veg oil a lot quicker and soon get my money back.

 

[alisterg]

Yep. like Extreedoc over the years I've looked yearningly at the engine heaters from Kenlow, Eberspacher or Webasto, but always thought they were too expensive to justify.

Seeing yours made me take another look, and it seems there are a number of cheaper - but no less capable - alternatives available now, which really make it a viable solution, so thank you very much for posting yours.

I came across this company, who have a presence on Ebay, as well as their own site:

https://www.t7design.co.uk/products/heating/engine-heaters-240v.html

and they sell both the heaters and all the necessary hoses, cables, connectors and whatnot that you could possibly need to install one.

I have no connection to the company at all, by the way, but the fact that it is a UK company with a shop and a phone number is very reassuring to me, rather than buying from an unknown on Ebay.

I will be looking at this seriously in the New Year once my bank balance has recovered from the festive season...

Al.

 

[paul123]

thanks for that the instructions are not too good

 

[Richie_asg1]

I particularly like "Reduce the cost of fuel consumption and winter warm library"

I fitted one of the Kenlowe box types a few years ago to another vehicle, and used 240V 32A blue hook-up style connectors. There is one type that is a fixed plug on a baseplate. (This one) I fitted that to the front apron with wires in flexi conduit back to about the same position as yours. They should come with a grey waterproof cover or at least mine did.
It worked brilliantly except when the snow came and I had to park nearer the road....and I didn't have a cable long enough!

I did wonder if that style had a pump and is good to know it has, although 1.5mmsq cable for 3kw is a bit on the small side. It will warm up. The kenlowe ones suffered with the pumps seizing up.

Certainly worth a go at that price,

 

[Series 1 2 & 3]

thanks for that the instructions are not too good

I took a better photo of the pipework today.

 

[Series 1 2 & 3]

I particularly like "Reduce the cost of fuel consumption and winter warm library"

Yes, the English translation of many items from abroad often leave me quite puzzled.

I did wonder if that style had a pump and is good to know it has, although 1.5mmsq cable for 3kw is a bit on the small side. It will warm up.

The cable is slightly warm after 25 minutes or so but nothing to worry about.
It is the same type of cable that is fitted to immersion heaters.

The kenlowe ones suffered with the pumps seizing up.

Certainly worth a go at that price,

I am using a 50/50 mix of antifreeze to minimise corrosion.
Unfortunately it is my experience that the cost of an item does not have much relationship with quality these days.

I wanted to spend as little as possible and fit it with minimum change to the original set up of the vehicle so that the whole process could be completely reversed if it doesn't work out as planned.

 

[Richie_asg1]

I was just thinking it could be a cheap solution to a campervan conversion using wet type radiators. Should be safer than open type heaters and is very compact.

Goodness knows why they give small T pieces - unless everything is that size on most cars new. Would be better just to buy the unit if possible as the extras sound useless.

 

[Extreedoc]

Just ordered one.

 

[Series 1 2 & 3]

I've just fitted another preheater to my S3 with the 200tdi engine and gearbox fitted.

Almost exactly the same installation, perhaps slightly easier as there was no tap to remove.

It took about 2 hours to do including making up the pipe work.

It works well I'm pleased to say.

TBH I'm surprised they do work so well.

I'd have thought that feeding the engine and heater matrix in parallel with one another would have resulted in the heater getting the lion's share of the heat and the block

staying cold, but it doesn't.

Originally I intended to feed the preheater via the engine drain plug hole in the block but thought I'd try the recommended method of fitting first.

 

[Extreedoc]

Mine arrived this morning, looks good so far but instructions in Russian!! I think I'm going to be grateful to Series 1 2 & 3 for his descriptions. I hope the voltage is right.

 

[Series 1 2 & 3]

Mine arrived this morning, looks good so far but instructions in Russian!! I think I'm going to be grateful to Series 1 2 & 3 for his descriptions. I hope the voltage is right.

Perhaps the easiest thing to get wrong is which way up it should go.
The flow arrows near the input and output of the preheater should be pointing upwards.