Series 3 200 Tdi

A couple of questions about fitting a 200 Tdi in a '79 88" Series III. I have an engine sourced and was wondering which Intercooler is the handiest to fit. The engine is from a '94 Disco, and I've asked him to throw in the Intercooler but he also has a couple of 300 Tdi 'coolers knocking about the yard so would one of them be any better? My own rad looks quite good and I'm hoping to be able to use it in the conversion. The Disco one is not the best so what should I do about an Oil Cooler, am I as well to try and fit the Disco Rad or try fit a standalone Oil Cooler?. Thanks in advance.....

There is little difference between disco and defender intercooler so chose the best
I would fit the whole disco frame with a new rad,keeping the system standard 200 disco means future replacement of any part or hose is simpler.

Ok, that makes sense alright.....

There is no single or right answer here. A lot will depend on what you are doing and want to achieve and how much money/effort you want to put in.


You are probably better off using a proper Tdi rad. While a Tdi can run cool. If you work it hard the series one may not be up to it. And the oil cooler is pretty important and easy to plumb with standard bits.


A new Disco rad isn’t that pricey. But you’ll need to fab up a bracket to support it.


Either way, you can’t fit a stock intercooler in the stock location on Series as the steering relay will be in the way.


If you plan on a Defender style front/grill then you may have room to do this. Or something else.


Putting a stock intercooler in front of the rad is difficult as the outlets on the intercooler are in the wrong place. You can get these adapted, but it’s expensive.


You might be able to adapt a TD5 or TDCi intercooler or an aftermarket one easier. Or not run an intercooler at all.

theres no right or wrong way people have done it a few different ways still i've still got the original 2.25 rad in mine with a 300tdi intercooler and turbo and external oil cooler

I have fitted an aftermarket performance inter cooler 300 tdi copy but thicker not fitted for performance but for routing the intercooler pipes better as the necks on the intercooler are at better angles which makes routing the pipes better.

You dont have to fit as a TDI you know...simpler to fit as a DI engine...just in case you dont know.

nickjaxe said:

You dont have to fit as a TDI you know...simpler to fit as a DI engine...just in case you dont know.

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Not fitting the turbo is hardly any less work tbh. And I simply can’t see the point in a low compression diesel with no turbo. You’d be lucky to be making more power than a stock 2.25 petrol and not have the fat torque curve of a Tdi.

Not trying to rain on your parade. But it would be a completely worthless conversion IMO.

300bhp/ton said:

Not fitting the turbo is hardly any less work tbh. And I simply can’t see the point in a low compression diesel with no turbo. You’d be lucky to be making more power than a stock 2.25 petrol and not have the fat torque curve of a Tdi.

Not trying to rain on your parade. But it would be a completely worthless conversion IMO.

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Far from completely worthless. A Di conversion is a good match for Series running gear, obviously not the same as running with a turbo but a sensible improvement on 2.25 petrol bhp with added diesel low down grunt.

It'd blow a 2.25 oil burner out the window.

Main downside it its a very noisy lump with no turbo.

I've had all 3, 2 1/4 diesel, petrol and 200Di in Series as daily drivers.

Had a 200di in mine for the best part of 10 years...cant say its noisy...quiter that the old 2.25 it replaces...maybe me having 3.5 diffs helps with the noise.

A very unstressed economical engine...stll going strong.

You’d probably be better off with a 2.5 Nad. The indirect injection is smoother and quieter than the direct injection engines. And you’ll have about the same power as “Di”.

Also you don’t get the low end grunt with a diesel when it has no turbo.

Only prob the 2.5 nad is a ****e motor....no better than the feeble 2.25d.

300bhp/ton said:

You’d probably be better off with a 2.5 Nad. The indirect injection is smoother and quieter than the direct injection engines. And you’ll have about the same power as “Di”.

Also you don’t get the low end grunt with a diesel when it has no turbo.

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Largely I agree but good 12Js are hard to come by.

If you think a 2.5 non turbo diesel has no low end grunt I don't recommend driving a 10H

nickjaxe said:

Only prob the 2.5 nad is a ****e motor....no better than the feeble 2.25d.

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I'd like a 17H in me ambulance though

nickjaxe said:

Only prob the 2.5 nad is a ****e motor....no better than the feeble 2.25d.

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Not sure what you mean. They share a common block, but it’s the same block that the Tdi’s use too. Obviously there are differences between them all. But they are more similar than not across all of them.

nickjaxe said:

Had a 200di in mine for the best part of 10 years...cant say its noisy...quiter that the old 2.25 it replaces...maybe me having 3.5 diffs helps with the noise.

A very unstressed economical engine...stll going strong.

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The Tdi is more noisy. Lots of info on the web. If you took an old neglected 2.25 out and replaced it with a 200 and new mounts and such. Then yes it may appear quieter. But it is only appearance.

Just like the 2.5 TD 19J is also smoother and quieter than a Tdi.


The real benefit of the Tdi’s are the turbo bit. And the ability to take the boost. In n/a form you get neither of these benefits.


I’m not saying it isn’t a good motor still. Just a lot of effort for little gain.


We know a 2.5 NAD makes 67hp. And a 2.5 TD 89hp. That’s a 22hp gain. A Tdi is intercooled and runs more boost and iirc the static CR is lower. So it is reasonable to assume a Tdi makes in excess of 22hp more than it would n/a.


107hp for a Defender 200Tdi minus say 30hp (but maybe more) is 77hp. A stock 2.25 petrol in good order makes 72hp and will be a heck of a lot more refined and quieter than the diesel.


I admit finding a NaD these days might be more difficult. And maybe you are making almost 10hp more. But it seems a lot of work and money to get what actually is a less refined engine and only 10hp on top.


Mpg wise. A turbo variant is unlikely to be any worse on fuel really. Hence why all modern cars striving for good mpg are turbocharged. And mpg only really matters if you are doing big mileage in a Series. Which most people probably aren’t.


I suspect for refinement a 2.5 petrol from a 90 would probably be quite a nice setup.


I’m not knocking your vehicle. But you may want to consider fitting a turbo. It will make a bigger difference than it did going from a 2.25 to what you have now.


As for tall gearing. 3.54 diffs and stock Series gearing otherwise does indeed make it taller. But tbh without a turbo probably a little too tall for some uses and at certain times. I bet you struggle to make much use of 4th gear under 40mph. And then only on the flat or downhill sections.