T25 Alternative Engine Forum

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Most liked posts	Author	Posted	Liked	Forum
Injector thread broken off on cylinder head (engine). What now?	meeh85	11 Apr 2026, 10:44	Once this week	T25 Alternative Engine Forum
Injector thread broken off on cylinder head (engine). What now?	Aidan	10 Apr 2026, 18:29	Once this week	T25 Alternative Engine Forum

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Last post

Petrol Alternative Engines...

Last post by silverbullet « 06 Apr 2024, 16:09
Replies: 10
by HarryMann » 15 Oct 2005, 01:57

Subaru Engine Types and Options

The normally aspirated (NA) flat 4's weigh about the same as a WBX and after installation there's always a cleaner...

10 Replies

128629 Views

Last post by silverbullet
06 Apr 2024, 16:09
Diesel Alternative Engines..... Read before asking questions

Last post by sdelasal « 09 Aug 2008, 22:43
Replies: 18
by admin » 13 Oct 2005, 09:35
1

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VW are renowned for their diesels and those fitted as standard to the T25 do not do it justice. What can you replace them with to getting better...
18 Replies

196813 Views

Last post by sdelasal
09 Aug 2008, 22:43
2.0 MkIII golf GTI engine swap - wiring

Last post by Aidan « Yesterday, 07:34
Replies: 1
by MissSpentYouth » 10 Apr 2026, 20:02

Hi All,

Just doing some research into a 2.0 mkIII golf GTi engine swap into a T25.

The mechanical side seems well documented and appears...

1 Replies

165 Views

Last post by Aidan
Yesterday, 07:34
Injector thread broken off on cylinder head (engine). What now?

Last post by meeh85 « 12 Apr 2026, 16:35
Replies: 9
by meeh85 » 10 Apr 2026, 09:43

Hi.
Greetings from Norway. I will try to explain in english..... :) And thanks a lot for reading this !!!

I have a 1989 VW T3. It’s supposed to...

9 Replies

732 Views

Last post by meeh85
12 Apr 2026, 16:35
Black smoke on acceleration.

Last post by DarrenC90 « 11 Apr 2026, 19:10

by DarrenC90 » 11 Apr 2026, 19:10

Hi all, thanks for any help in advance.
So 1.9TD Aaz vanny. Replaced head gasket, valve stem seals, injector nozzles (pop tested to within 5bar or...

0 Replies

94 Views

Last post by DarrenC90
11 Apr 2026, 19:10
Headache trying to bleed my fuel pump

Last post by axeman « 06 Apr 2026, 16:54
Replies: 5
by aimlessrock » 05 Apr 2026, 07:39

I changed the fuel filter in my van (1.9 AEF diesel) and I just can’t get the van to now start.

Any tips on how to best bleed the pump?

Thanks

5 Replies

618 Views

Last post by axeman
06 Apr 2026, 16:54
Temp sensor retaining clip hell(p)

Last post by redsnapper « 04 Apr 2026, 19:41
Replies: 17
by redsnapper » 31 Mar 2026, 17:10
1

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Hi all,

Not posted on here for a long time but regular browser for solutions but can't find an answer to this and feel I am just being an idiot

1Y...
17 Replies

3619 Views

Last post by redsnapper
04 Apr 2026, 19:41
TSR engine conversions question

Last post by mrhutch « 27 Mar 2026, 15:48
Replies: 2
by Swordfish93 » 27 Mar 2026, 08:00

Has anyone used them recently? I see bad reviews from quite a few years ago and want to know if they have changed there ways or not

2 Replies

21820 Views

Last post by mrhutch
27 Mar 2026, 15:48
Which gearbox.

Last post by cobblers « 14 Mar 2026, 15:47
Replies: 5
by HappyCamper » 13 Mar 2026, 13:24

Hi, Anyone know what the best gearbox would be best to run with a golf agg engine. I'm presuming the original 1.6 diesel box will be too low gearing,...

5 Replies

27519 Views

Last post by cobblers
14 Mar 2026, 15:47
T25 Engine Swap HELP...

Last post by Stesaw « 04 Mar 2026, 13:16
Replies: 27
by monsterVW1982 » 18 Apr 2011, 10:09
1

2
Hi all,

After a little bit of advise with selecting a new enginer, gearbox and a turbo for my van after the current engine give up the ghost on the...
27 Replies

69513 Views

Last post by Stesaw
04 Mar 2026, 13:16
oil pump/vacuum pump problem

Last post by Aidan « 02 Mar 2026, 18:55
Replies: 2
by morganite » 28 Feb 2026, 21:21

Hi, need some help please! AAZ conversion, lost the oil pressure because the new 2,000 ml 1.9td oil pump male tang was,nt reaching into the female...

2 Replies

12307 Views

Last post by Aidan
02 Mar 2026, 18:55
Coolant issues

Last post by BarnyE « 28 Feb 2026, 21:08
Replies: 5
by BarnyE » 28 Feb 2026, 13:59

Hi, I’ve been rebuilding my van for the last 12 months, it got delivered on a trailer and I’m almost ready for its first test.

But I’m having an...

5 Replies

13958 Views

Last post by BarnyE
28 Feb 2026, 21:08
AHU turbo question

Last post by hotpod « 27 Feb 2026, 15:46
Replies: 9
by hotpod » 12 Feb 2026, 10:56

I have an AHU engine with a KKK turbo which has a pipe from the compressor to the N75 and one from the N75 which goes back to the turbo to operate...

9 Replies

24404 Views

Last post by hotpod
27 Feb 2026, 15:46
Whining when accelerating

Last post by peteandnero « 25 Feb 2026, 16:43

by peteandnero » 25 Feb 2026, 16:43

Hi,
my AFN TDI conversion 5 speed Westfalia has recently developed a new sound. When accelerating in 4th or 5th there is a woooo type noise which...

0 Replies

20058 Views

Last post by peteandnero
25 Feb 2026, 16:43
1y identification

Last post by davidoft1 « 12 Feb 2026, 10:47
Replies: 9
by BarnyE » 08 Feb 2026, 10:16

I have a 1900 1y conversion in my van and want to do a belt change on it.
Unfortunately I don’t know the source of the engine. I’m looking at serial...

9 Replies

23602 Views

Last post by davidoft1
12 Feb 2026, 10:47
CS to AGG engine swaps

Last post by cobblers « 30 Jan 2026, 09:06
Replies: 2
by HappyCamper » 29 Jan 2026, 18:54

Hi, I was looking for info, on changing a CS diesel engine for an AGG. There seems to have been plenty done, but I can't see much info. I've tried...

2 Replies

17489 Views

Last post by cobblers
30 Jan 2026, 09:06
Which petrol engines.

Last post by axeman « 16 Jan 2026, 17:44
Replies: 9
by HappyCamper » 09 Jan 2026, 13:56

Hi, a few more questions on engine swaps. I've seen info on swapping from diesel to petrol. The good thing is I'm more comfortable working on petrol...

9 Replies

31909 Views

Last post by axeman
16 Jan 2026, 17:44
1.9 Tdi upgrade , issues , solutions

Last post by HappyCamper « 08 Jan 2026, 11:14
Replies: 10
by dcworm57 » 27 Nov 2025, 15:33

I’m considering 1.9 Tdi upgrade to my 1.6jx westy . It’s now on Brickwerks high lift kit and I’m told by various sources that 1.9 Tdi wont work on...

10 Replies

29284 Views

Last post by HappyCamper
08 Jan 2026, 11:14
Diesel Injection Pump.

Last post by lefty67 « 18 Nov 2025, 19:17
Replies: 1
by Burtybassett » 15 Nov 2025, 16:49

Hiya 👋

Does anyone know of anyone that would/can refurb a Diesel Injection Pump ?
1.9TDi - AHU Engine
Think it's a Bosch pump - 028 130 115 M...

1 Replies

20173 Views

Last post by lefty67
18 Nov 2025, 19:17
Re-mapping AHU TDI

Last post by ZsZ « 30 Oct 2025, 14:37
Replies: 14
by hotpod » 02 Sep 2025, 13:25

Is this possible?
When I put the engine in 12 years ago, I thought I could get it re mapped ( because it has an ECU) to suit pushing a Syncro Westy...

14 Replies

43881 Views

Last post by ZsZ
30 Oct 2025, 14:37
Coolant Type for Subaru EJ20 Engine Conversion

Last post by Basilakios « 24 Sep 2025, 12:13
Replies: 7
by Basilakios » 17 Sep 2025, 11:45

Another week and another new problem to deal with.

I've not had this T25 campervan for long and barely driven it anywhere due to an ongoing issue...

7 Replies

38655 Views

Last post by Basilakios
24 Sep 2025, 12:13
AAZ diesel pump leak

Last post by Al Housman « 13 Sep 2025, 20:28
Replies: 5
by Al Housman » 13 Sep 2025, 14:58

The truck is finally going after being stood for about 2 years and sounds really good.

There is however a steady leak from under the diesel pump. I...

5 Replies

32969 Views

Last post by Al Housman
13 Sep 2025, 20:28
AFN TDI Obd scanner

Last post by Robsey « 07 Sep 2025, 20:53
Replies: 3
by fh9977 » 04 Sep 2025, 12:31

Hi, would anyone be able to recommend an OBD device I can connect to the port of an ATF TDI engine to read live data? Is it possible to have a...

3 Replies

32011 Views

Last post by Robsey
07 Sep 2025, 20:53
Retro fit engine from a Golf GTI to a 1.9

Last post by Ukjamie82 « 04 Sep 2025, 13:00
Replies: 5
by Ukjamie82 » 02 Sep 2025, 06:09

Good morning all

I am in the throws of retro fitting a 1.9 water cooled engine from a 1.8 Golf GTI , reason , ecu failed and could not find a...

5 Replies

33668 Views

Last post by Ukjamie82
04 Sep 2025, 13:00
T25 legacy conversion wiring loom issue

Last post by ManicGTI « 03 Sep 2025, 21:13
Replies: 2
by Paul1981 » 27 Aug 2025, 20:37

Hi everyone
Please can anyone advice me on where i can source a wiring diagram for a 3 pin ECU connection from a Subaru Legacy. I’m not sure what...

2 Replies

31703 Views

Last post by ManicGTI
03 Sep 2025, 21:13
Help! Timing belt creeping off cog

Last post by colinthefox « 30 Aug 2025, 18:48
Replies: 8
by sopranolady » 26 May 2016, 09:36

Hi, apologies if this is the wrong category for the post, I'm looking for urgent advice, having hit a snag with our engine fitting project.

Our 1990...

8 Replies

38584 Views

Last post by colinthefox
30 Aug 2025, 18:48
Throttle Potentiometer Issue

Last post by TwinTurbo « 16 Aug 2025, 12:36
Replies: 6
by Nistorph » 21 Jul 2025, 20:40

Hi,

I’m looking for some guidance please.

I have a T25 fitted with a 1.9 AHU TDI lump. It now, with increased frequency, reverts to some sort of...

6 Replies

642392 Views

Last post by TwinTurbo
16 Aug 2025, 12:36
Part Identification

Last post by Oldiebut goodie « 13 Aug 2025, 14:01
Replies: 7
by Bison535 » 13 Aug 2025, 10:13

Early Bay T2 with petrol engine 1.6 has difficulty in running and suspect a ‘sensor’ fault!?! Have removed this Sensor Unit but cannot identify which...

7 Replies

35960 Views

Last post by Oldiebut goodie
13 Aug 2025, 14:01
Glow plugs T3 tdi

Last post by Simon Baxter « 11 Aug 2025, 13:10
Replies: 3
by Kougar38s » 24 Jul 2025, 10:56

Hi all, I'm a new member and a new owner of a 1989 T3 tdi 1.6.
I wonder if any one can help with a problem I'm having. Its only just started. The...

3 Replies

35236 Views

Last post by Simon Baxter
11 Aug 2025, 13:10
1.9DG to diesel swap.

Last post by DavidS « 10 Aug 2025, 21:37

by DavidS » 10 Aug 2025, 21:37

I used to own a T25 with a 1.7KY engine which not obviously not quick, but it was very reliable and pretty economical. I had planned to put a 1Y in...

0 Replies

49154 Views

Last post by DavidS
10 Aug 2025, 21:37
Cosworth 2.9litre in my Crewwy

Last post by dickspanner « 07 Aug 2025, 19:53
Replies: 302
by dickspanner » 04 Jul 2006, 15:56
1

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17

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19

20

21
Hi folks

Not been on for a while but have just farmed through all V6 threads again.

I have gone and done it, I have bought the Granada Cosworth...
302 Replies

338108 Views

Last post by dickspanner
07 Aug 2025, 19:53
1.6d to 1y the definitive guide

Last post by JonathanUSSF « 30 Jul 2025, 10:50
Replies: 103
by weldore » 15 Aug 2012, 16:05
1

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6

7
theres been a few people over the years gone this route including myself and have had to ask questions or trawl through the alt forum for answers and...
103 Replies

734417 Views

Last post by JonathanUSSF
30 Jul 2025, 10:50
Power steering pump

Last post by Aidan « 27 Jul 2025, 09:14
Replies: 2
by paradox » 26 Jul 2025, 16:09

I’ve a 1.9 TDi Passat engine in my van
Despite fitting a new belt and making sure it’s tensioned correctly
It slips the belt and squeals at full...

2 Replies

359040 Views

Last post by Aidan
27 Jul 2025, 09:14
1.9d 1Y exhaust.

Last post by BarnyE « 26 Jul 2025, 18:37

by BarnyE » 26 Jul 2025, 18:37

Hey all, been reading up on this and I’ve got myself more confused than ever.

So long story short inherited someone else’s bodge of a conversion....

0 Replies

370895 Views

Last post by BarnyE
26 Jul 2025, 18:37
AAZ VS Air cooled

Last post by dcworm57 « 16 Jul 2025, 05:12
Replies: 6
by davegeezzer008 » 27 Jun 2025, 19:58

Im having problems getting my AAZ pump rebuilt as bosch don't make many parts for the VE pump any more, so I'm just thinking ahead about my options...

6 Replies

159524 Views

Last post by dcworm57
16 Jul 2025, 05:12
Engine swop question

Last post by colinthefox « 11 Jul 2025, 21:08
Replies: 1
by aimlessrock » 11 Jul 2025, 19:43

Hi,

I was looking at the engine in my t25 and noticed that someone has tipped the letters AEF on it.

It looks different to the pictures of the...

1 Replies

33787 Views

Last post by colinthefox
11 Jul 2025, 21:08
AAZ upgrade turbo and realistic power

Last post by syncroandy « 08 Jul 2025, 14:55
Replies: 1
by TommyJenko » 21 Jun 2025, 16:40

Hi guys I have a AAZ in bits that came with my van, I was going to rebuild it but looking at the turbo it’s a kkk-k03 which seems a bit small for the...

1 Replies

34281 Views

Last post by syncroandy
08 Jul 2025, 14:55
1.8T Sump Bolt Access

Last post by Vaughanylive « 06 Jul 2025, 07:43

by Vaughanylive » 06 Jul 2025, 07:43

I’ve got a 1.8T converted Syncro (AUM stamped block, but cable throttle) with a custom mild-steel sump made by whoever did the conversion. The paint...

0 Replies

53764 Views

Last post by Vaughanylive
06 Jul 2025, 07:43
AHU TDI Vibration Damper Pulley testing

Last post by hotpod « 28 Jun 2025, 08:52
Replies: 8
by hotpod » 31 Mar 2025, 15:29

Does anyone know how to test if the vibration damper pulley ( harmonic balancer) on the crank shaft is in good shape?
Mine drives the ribbed...

8 Replies

42440 Views

Last post by hotpod
28 Jun 2025, 08:52
AGG seized - Oil starvation on steep inclines?

Last post by silverbullet « 20 Jun 2025, 06:42
Replies: 15
by Hansa » 04 May 2025, 10:24
1

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Not quite the first post I planned to make, but 2k miles after buying an AGG engined '86 Syncro, it stalled as I pulled into my garage. 30 minutes of...
15 Replies

54419 Views

Last post by silverbullet
20 Jun 2025, 06:42
TDI annoying pause when pulling away

Last post by syncroandy « 15 Jun 2025, 16:14
Replies: 9
by hotpod » 06 Jun 2025, 09:22

1997 AHU ETDI
The question is: When I first pull away in the van, it starts moving then has an annoying momentary drop in revs after which it is...

9 Replies

38964 Views

Last post by syncroandy
15 Jun 2025, 16:14
Subaru ej20 engine swap education wiring

Last post by R0B « 15 Jun 2025, 09:39
Replies: 3
by Mansfldfox » 12 Jun 2025, 16:09

Hi I have a 1984 t25 campervan which I have fitted a Subaru ej20 non turbo engine I need help with the wiring of the Ecu i have both the Subaru and...

3 Replies

33156 Views

Last post by R0B
15 Jun 2025, 09:39
Alternator/water pump drive belt - adjustment

Last post by Lio « 12 Jun 2025, 17:21
Replies: 8
by Bison535 » 04 Oct 2024, 02:27

Hi 80-90 guys
There always seems a need to make adjustment to the tension of my drive vee belt ! Once I hear a squeal I know it needs adjustment...

8 Replies

73003 Views

Last post by Lio
12 Jun 2025, 17:21
Oil Capacity (Diesel 1Y Engine)

Last post by The Hairy Camper « 10 Jun 2025, 15:54
Replies: 2
by The Hairy Camper » 10 Jun 2025, 15:40

Just replaced a leaky sump gasket/baffle plate. Drained all the oil, replaced oil filter, and refilled with 4.5L of 15W40 oil. However, the dipstick...

2 Replies

32363 Views

Last post by The Hairy Camper
10 Jun 2025, 15:54
1z tdi ecu

Last post by bundyboy « 10 Jun 2025, 08:34
Replies: 5
by Wallace748 » 14 Oct 2015, 19:03

Hi, I'm running a 93/94 1z tdi with the 68 pin ecu. Struggling to get coms via diagnostic plug( it's the old two pin type) anyone help me out with...

5 Replies

31694 Views

Last post by bundyboy
10 Jun 2025, 08:34
4 digit pin code for AHU ECU Login?

Last post by hotpod « 30 May 2025, 07:47
Replies: 4
by hotpod » 29 May 2025, 08:20

Does anyone know a way to find the 4 digit pin that VCDS requires to be able to do things like add new keys?
I've been reading a lot of forums but...

4 Replies

28638 Views

Last post by hotpod
30 May 2025, 07:47
1Y coolant pipes/system

Last post by colinthefox « 21 May 2025, 20:34
Replies: 15
by BarnyE » 30 Mar 2025, 14:20
1

2
Hi all, my van has had a 1Y engine swap in the past. Whoever swapped it seemed to have ran out of enthusiasm once the got to the coolant system and...
15 Replies

57305 Views

Last post by colinthefox
21 May 2025, 20:34
Subaru Engine Identification Needed

Last post by Basilakios « 20 May 2025, 16:25
Replies: 5
by Basilakios » 19 May 2025, 21:41

Hi!
I've very recently bought a new (to me) T25 which has a Subaru engine. I wasn't especially looking for one with a Subaru engine but it drove...

5 Replies

35314 Views

Last post by Basilakios
20 May 2025, 16:25
1.8T Wiring/Fault Codes

Last post by Splurt « 17 May 2025, 10:54
Replies: 17
by Vaughanylive » 29 Apr 2025, 18:44
1

2
I’ve got a T25 Syncro with a 1.8T conversion (AGU) which seems to be running ok but out of curiosity I plugged it into my VCDS Lite which is showing...
17 Replies

61190 Views

Last post by Splurt
17 May 2025, 10:54
AHU immobiliser stuck on. Help please

Last post by hotpod « 14 May 2025, 09:27
Replies: 6
by hotpod » 03 May 2025, 09:41

1997 VW Golf AHU tdi in a T3 van. Installed in 2014

I went to leave work the other evening and the van started for a second and then died. I am...

6 Replies

38491 Views

Last post by hotpod
14 May 2025, 09:27

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