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Retro Fit 2.1 oil cooler to early van

Posted: 15 Mar 2026, 22:35
by Robsey
Hi All,

You are bound to ask, but yes I still haven't fully plumbed in my 2.1 wbx into my 1983 van.

I have read a few posts where people have retrofitted the oil cooler despite having the early cooling system in the van.

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So a very simple question.
Has anyone got pictures or advice on how to achieve this?

I assume that I will need a later thermostat housing to plumb into

I am sure with some thought I could suss it out, but why re-invent the wheel if others have done it successfully already?

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Re: Retro Fit 2.1 oil cooler to early van

Posted: 19 Mar 2026, 07:25
by silverbullet
You will need to find a way to bleed off a small amount of coolant from the pump to the interwarmer (it also helps to warm the oil before the thermostat opens, helping the engine get up to operating temp faster for better emissions)
Not a problem with the late pump because it has such a feature, however no use to you with the early system...
The coolant then has to return to the "cold" side of the system, essentially creating a small circuit running parallel to the main coolant flow, much the same as the heater.
On the late system, this is via a spigot on the engine side of the thermostat housing which has a restricted bore, about 6mm or so.
In truth, the flow path is probably the other way round: coolant bleeds off from the stat housing, through the interwarmer and is drawn back into the pump.
HTH?

Re: Retro Fit 2.1 oil cooler to early van

Posted: 19 Mar 2026, 14:03
by Robsey
Thank you dear chap for your in-depth reply.

I have a later type thermostat housing on my desk at work.
I have a few ideas to play with,
Possibly fitting the later thermostat housing, but with the thermostat removed.
More or less acting as a distribution / junction point for the various pipes.

I am making up a GW / DH style cross engine pipe, so can potentially add the necessary additional take-off spigot as I go along.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 22 Apr 2026, 18:51
by silverbullet
I've got a couple of so-so used syncro type (cast alloy) thermostat housings that you could use as a bypass manifold for small pipes, obviously you'll need to blank off the top where the thermostat housing bonnet fits and also the main coolant outlet.
But it could solve a few problems in one hit.

Strangely enough I am reading through my VAG Service wokshop manual for the DH/GW as that also applies to my early wbx6. It uses a Digijet variant that has a DJ type advance/retard dissy, an early style two-switch type throttle body and also lambda control.

But the idle valve is the later electrical servomotor type, not the early bimetallic spring disc valve one.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 22 Apr 2026, 19:56
by ajsimmo
I solved this problem by fitting a Laminova in-line oil cooler into the big coolant hose under the coil. Oil feed was via a sandwich plate under the filter. The owner reported great results, with nice stable oil temps in all conditions.

viewtopic.php?p=8229534#p8229534

E D I T: linky now worky

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Re: Retro Fit 2.1 oil cooler to early van

Posted: 22 Apr 2026, 20:44
by Robsey
I am sort of getting there with this.
Managed to hook-up the oil cooler and fit the plastic thermostat housing.

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I am going to link the big stub on the plastic thermostat housing to the free flowing stub of the alloy thermostat housing.
And then omit the thermostat controlled stub, by fitting a blanking plate instead.

Pipe connected to the wrong stub...
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Both radiator feed and return pipes are more or less sorted too. Just need to cut down the main pipes to stop short of the firewall.
Then I can fit the hoses.
All thermostat and distribution tower hoses received from Holmfirth ready for fitting.
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What slightly confuses me is the routing of the return pipe to the heater matrix (heat exchanger).

I can see where it exits the metal pipe to the thermostat, but no idea of it's routing back to the hose at the firewall.

But overall... it is starting to make sense.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 23 Apr 2026, 06:51
by silverbullet
Seems like an awful lot of effort to end up with a mongrel coolant system that may or may not work properly? Remind me why you didn't just convert it to the later coolant system and be done with it?
If you connect the two thermostat housings together 1. Its another long hose to let you down and more importantly 2. Will this not create a large bore bypass loop across the LH head, causing coolant stagnation?

Re: Retro Fit 2.1 oil cooler to early van

Posted: 23 Apr 2026, 12:02
by Robsey
I presume you are right.

Time to wind my neck in, and do it properly.
I have about 75% of the later system installed now anyway.

A few hoses across the pulley end of the engine,
Water pump and bleed rail, and we are probsbly there.

In the interest of trying to cut financial corners, I have probably spent double by faffing about.

Sometimes I over think and over complicate things.
This is one of those times.

UPDATE:-
I have ordered the remainder of the water pipes and pump from Brickwerks,
And the bleed rail from Heritage.

One thing I cannot find is the later type expansion tank holder that sits on the heat shield.
The one that came in my engine in 2012 was very flaky with rust.
I will put a wanted thread up.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 29 Apr 2026, 14:15
by MatikoT31.6TD89
Hi silverbullet,
I am pretty new to the forum and trying to restore my family T3 1.6TD JX Transporter which sits in Rome, in order to drive it back to London...as a thriumpant ride!
But before that happen I'll need to restore this famous JX engine!

Would you mind sharing the JX service manual as it seems a perfectstarting point.

Thank you

Max

Re: Retro Fit 2.1 oil cooler to early van

Posted: 30 Apr 2026, 06:24
by silverbullet
You need to go to the syncrosport website and look at the manual archive there.

Its not my site.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 04 May 2026, 22:43
by Robsey
Back on Topic, as they say...

I have ordered and fitted most of the later pipe work to the van.

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What a total pig to get at a lot of the nuts...
VW really did not make it easy to work on these vans with everything packed so close together.

Universal joint on a 1/4" drive socket was the only way to get at many of the nuts and bolts.

One thing I did find was the refusal of the steel pipe to bolt onto the water pump...
The pump was very slightly out on hole pitch compared to the original metal pipe.
Ended up opening up the mounting holes on the steel pipe to 9.5mm diameter.
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Being a complete baffoon, I have ordered the wrong bleed rail.

I have ordered the rail for the pick-up , not for a van.
Have I given myself another headache.?

Re: Retro Fit 2.1 oil cooler to early van

Posted: 05 May 2026, 12:20
by silverbullet
Send it back. The pickup truck has a much smaller top hatch aperture and the bleed rail follows its perimeter.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 05 May 2026, 22:11
by Robsey
I have emailed Heritage...

We shall see what happens.

Re: Retro Fit 2.1 oil cooler to early van

Posted: 07 May 2026, 20:33
by ajsimmo
https://brickwerks.co.uk/product/coolan ... stainless/

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Re: Retro Fit 2.1 oil cooler to early van

Posted: 07 May 2026, 23:10
by Robsey
Thanks for the link dear chap...

Much appreciated..