Madbrick1995
New member
- Joined
- Jan 20, 2026
- Location
- Poland
I ser mine sugestion helped . I very happy you about your progress
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Diesel swap
- Thread starter Bilbo19
- Start date
nordmaschine
forced instruction
- Joined
- Feb 12, 2012
- Location
- The Balkans, BiH
Why m-TDI?
Immo-off on EDC15/16 is super easy, and it doesn't take much more wiring than a D24 to make it work. You can even keep cable accelerator pedal, put a potentiometer from Mk3 under the hood, hook up the kickdown cable to it and be on your way.
Madbrick1995
New member
- Joined
- Jan 20, 2026
- Location
- Poland
In my opinion stay in style of oldschool diesel what fits in 940 and 740
Yes I know, maybe in the future I will go to EDC, but at the time I started this project I was in a mood to keep it 100% mechanical, and as similar as possible to the original engine. Which I still find cool for the moment, but yes I eared about all the disagreement related to m-tdi pumps... Well, we'll see!
Yes thank you!
Well you were right, D24 and AAT/AEL sensors doesn't work the same way (I think D5252t work the same way as the D24, open circuit when pressure comes).
W signal and oil pressure light issues are resolved. I now have to change the PS pump, I know the V70II tdi pump works but I don't know yet if it fits on the bracket I have. I will solve it soon!
My m-tdi pump is done now, I will receive it next week, so maybe a first start coming soon!
The guy who built me this pump has already cranked it on a AEL engine (clic for video) :
42519212 by Bilbo 19, sur Flickr
Yes thank you!
Well you were right, D24 and AAT/AEL sensors doesn't work the same way (I think D5252t work the same way as the D24, open circuit when pressure comes).
W signal and oil pressure light issues are resolved. I now have to change the PS pump, I know the V70II tdi pump works but I don't know yet if it fits on the bracket I have. I will solve it soon!
My m-tdi pump is done now, I will receive it next week, so maybe a first start coming soon!
The guy who built me this pump has already cranked it on a AEL engine (clic for video) :
42519212 by Bilbo 19, sur FlickrYes didn't seen your post but I agree with that !
As the original 6 cylinders oil pan was previously shortened, the oil pipe relief on the pan interfered with the sway bar, I made two spacers 23,5mm thick in aluminum so I can have enough clearance (maybe I should have do more, if I swap for a bigger sway bar later?).
And also installed definitively this original oil cooler from D24tic :
And also installed definitively this original oil cooler from D24tic :
Fabricated an adaptation for coolant temp sensor with an old sensor I drilled and threaded to M10x100
I made the wires for glow plugs but I have to redo that cause I forgot the mechanical vacuum pump that will take place in the middle of the head...
I made the wires for glow plugs but I have to redo that cause I forgot the mechanical vacuum pump that will take place in the middle of the head...
Nice progress! Track your oil temps with that cooler, to be sure that the thermostat is working good!
If you still havent installed the mechanical vacuum pump, consider installing an electronic from some newer volvo. It can reduce the risk of camshaft breakage.
We installed one in my friends D24 245 after some bad quality oil bought in Ireland chewed up the lobe surface... Adjustable vacuum pressure switch (with hysteresis) and you are good to go. It does not build vacuum that quick as the mechanical one, but good enough for normal road use.
If you still havent installed the mechanical vacuum pump, consider installing an electronic from some newer volvo. It can reduce the risk of camshaft breakage.
We installed one in my friends D24 245 after some bad quality oil bought in Ireland chewed up the lobe surface... Adjustable vacuum pressure switch (with hysteresis) and you are good to go. It does not build vacuum that quick as the mechanical one, but good enough for normal road use.
Hey thank you! but I'm not sure to understand well what you just said?
Yep I know about that, I considered installing an electric one but I didn't found a proper V70 or XC90 at the junkyard to tear those parts apart.
I had no working pumps for TDIs but the one from my D24 fits perfectly and works well with no additional noise so I decided to go this way for the moment. Maybe I'll electric swap it in the future if I find those parts someday!
I'm really happy to be close off the "end" of this project, but a bit anxious too if something go wrong
The thermostat in the stock wahler plate can go bad over time (most of them already 30y+), so it is a good idea to install an oil temp gauge to see the actual oil temperatures. A partially stuck open tstat will overcool the engine in normal usage, and the cooling wont be effective at higher loads either. A stuck close tstat will let it warm up nicely, but the radiator wont have any actual cooling effect.
You can also check the pan and the radiator with a laser thermometer or hand touch. Tstat opens around 75cels.
You will love it!
I found myself also thinking this throughout the project. But once you have all the parts thought out and fabricated, even if you encounter some problems, just source another engine and bolt over all the stuff in a weekend!
Yeah you're right, it's reassuring to have all the mods done! And also to have nothing modified on the shell, so if something goes very wrong I can just source a good D24tic and bolt it right in.
So for the thermostat thing, if I understand well the thermostat is in the plate I sourced from a D24tic, between the block and oil filter?
Part n°1 :
I didn't knew that, but the oil temp is monitored on the original AAT/AEL block, so can I just wire the sensor to an oil temp gauge I find somewhere?
And what if the thermostat is stuck? Can I just part it out an clean it or something?7
Is that's why you chose the water/oil exchanger instead?
Thanks a lot for having noticed that to me!
So for the thermostat thing, if I understand well the thermostat is in the plate I sourced from a D24tic, between the block and oil filter?
Part n°1 :
I didn't knew that, but the oil temp is monitored on the original AAT/AEL block, so can I just wire the sensor to an oil temp gauge I find somewhere?
And what if the thermostat is stuck? Can I just part it out an clean it or something?7
Is that's why you chose the water/oil exchanger instead?
Thanks a lot for having noticed that to me!
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1995 Volvo 940 LPT project, from daily to semi-sleeper build
Greetings, Been lurking on this forum for quite some time now but never really contributed so I figured I make an thread which could be helpful/entertaining to some people. I own a 1995 Volvo 940 2.3 LPT sedan for about 5 years now. Its been my daily and over the years I added some stuff and...
turbobricks.com
Some info here. It's for a redblock but I'm assuming probably maybe the sandwich plate is the same part?
nordmaschine
forced instruction
- Joined
- Feb 12, 2012
- Location
- The Balkans, BiH
If the thermostat is stuck, wax element inside it has internally failed, the spring has become too weak, or something like that and there is nothing you can do about it. Oroginal is made by Wahler and NLA/was not even sold separately IIRC, but you can replace it with an aftermarket clone.
It is in the part "1" in your diagram, as pictured side facing front, there is a circlip that retains it.
It looks something like this:
Worst case scenario, you can cut it up and completely disable it and put an inline thermostat from one of those fancy ebay stores, something like this:
Either way, it is important that you have working thermostat in there, because too cold oil kills those things fast, and overheated oil is no good either.
I like your progres, you are almost there, keep it up!
It is in the part "1" in your diagram, as pictured side facing front, there is a circlip that retains it.
It looks something like this:
Worst case scenario, you can cut it up and completely disable it and put an inline thermostat from one of those fancy ebay stores, something like this:
Either way, it is important that you have working thermostat in there, because too cold oil kills those things fast, and overheated oil is no good either.
I like your progres, you are almost there, keep it up!
I had to change my plans on PS pump bracket. I installed a 850 pump and bracket (with the reservoir on the pump), but it was interfering with the hood. So I had to change for a V70II pump and bracket, witch doesn't interfere even if the pulley is very close to the hood.
PS hose was too short with the V70II setup, so I just took a banjo form an Audi PS hose and welded it very carefully on the original hose.
I mig welded that cause I don't have an other welding method available, but let me know if someone think this is a too risky?
I mig welded that cause I don't have an other welding method available, but let me know if someone think this is a too risky?
Great updates, very nice work and looks almost ready to run!
If my memory is correct, the sway bar from a V6 700 series has a deeper drop section that may be a good solution to the interference with your oil pan. Although I imagine using the spacers to block it down is also fine. V6 700 series are unfortunately rare here in the US, underappreciated and limited sales, but I believe they were more common in Europe where people have a better taste for refined machinery
, so you may be able to find one of those V6 bars without too much trouble.
I probably would have used a compression fitting on the power steering connection, but if the weld holds up, nothing wrong with that method as far as I can see.
Great input from @petiww and @nordmaschine here on the oil cooler tstat and vacuum pump decisions. I personally prefer the original style mechanical vac pump as a simple solution but electric pumps definitely work well, especially if you ever start having problems with the mechanical setup. I would add a large vacuum reservoir if you go that route though, since most electric pumps cannot recover as fast as the mechanical unit can, and you don't want to run out of brake assist if you need to do two hard stops close together.
As for oil cooler, agree that control of oil temp is critical on this engine, especially since the piston cooling jets add an enormous amount of heat to the engine oil on the direct injected TDI engine (even more so than a gasser or prechamber diesel, thanks to the combustion bowl in the piston that adds heat-absorbing surface area). If the oil cooler is not working correctly, you'll have overheated oil AND overheated pistons. I have seen what happens when TDI pistons overheat and it's not pretty, cylinder scoring etc.
VW/Audi standard solution to this is an oil-to-coolant heat exchanger. Then you no longer need to care about the thermostat in the oil-to-air sandwich plate: the coolant temp, regulated by the coolant thermostat, does all the work for you. Also helps warm the engine oil up more quickly from cold, working in reverse. A better and more controllable system all around, and certainly the industry standard approach nowadays. Factory D24T uses the coolant-based exchanger, although the D24TIC does not, using Volvo redblock-style plate that you have now. Factory TDI engines to my knowledge all use the coolant-based exchanger. There are different sizes of the coolant-type sandwich plate, including larger-capacity ones on PD130 TDI and later TDI 4cyl engines. Personally I would probably go that route. It also reduces plumbing complexity, no external oil cooler hoses, and means you can have one less heat exchanger core up in the cooling stack. But the other choices mentioned above are all good solutions too.
My only other comment is to be a little careful about your placement of that temperature gauge probe in the outlet for the upper radiator hose. That will work as long as the thermostat is open, but may not read accurately if the tstat is closed OR if it's failed shut and risking engine overheat. It's probably close enough to the main cylinder head water passages that it will always give you some useful information. But personally I would be more confident in its readings if it had its probe located in a coolant passage that sees constant flow regardless of thermostat position, such as the heater circuit (provided you don't have a heater control valve), oil cooler circuit if you had one, etc. The late D24T engines had it located in the return from the cold start thermostat circuit. You could build a small diameter bypass from the upper radiator hose outlet to mimic that setup, even though your IP doesn't have that feature (and won't need it with direct injection).
Cheers!
If my memory is correct, the sway bar from a V6 700 series has a deeper drop section that may be a good solution to the interference with your oil pan. Although I imagine using the spacers to block it down is also fine. V6 700 series are unfortunately rare here in the US, underappreciated and limited sales, but I believe they were more common in Europe where people have a better taste for refined machinery
, so you may be able to find one of those V6 bars without too much trouble.I probably would have used a compression fitting on the power steering connection, but if the weld holds up, nothing wrong with that method as far as I can see.
Great input from @petiww and @nordmaschine here on the oil cooler tstat and vacuum pump decisions. I personally prefer the original style mechanical vac pump as a simple solution but electric pumps definitely work well, especially if you ever start having problems with the mechanical setup. I would add a large vacuum reservoir if you go that route though, since most electric pumps cannot recover as fast as the mechanical unit can, and you don't want to run out of brake assist if you need to do two hard stops close together.
As for oil cooler, agree that control of oil temp is critical on this engine, especially since the piston cooling jets add an enormous amount of heat to the engine oil on the direct injected TDI engine (even more so than a gasser or prechamber diesel, thanks to the combustion bowl in the piston that adds heat-absorbing surface area). If the oil cooler is not working correctly, you'll have overheated oil AND overheated pistons. I have seen what happens when TDI pistons overheat and it's not pretty, cylinder scoring etc.
VW/Audi standard solution to this is an oil-to-coolant heat exchanger. Then you no longer need to care about the thermostat in the oil-to-air sandwich plate: the coolant temp, regulated by the coolant thermostat, does all the work for you. Also helps warm the engine oil up more quickly from cold, working in reverse. A better and more controllable system all around, and certainly the industry standard approach nowadays. Factory D24T uses the coolant-based exchanger, although the D24TIC does not, using Volvo redblock-style plate that you have now. Factory TDI engines to my knowledge all use the coolant-based exchanger. There are different sizes of the coolant-type sandwich plate, including larger-capacity ones on PD130 TDI and later TDI 4cyl engines. Personally I would probably go that route. It also reduces plumbing complexity, no external oil cooler hoses, and means you can have one less heat exchanger core up in the cooling stack. But the other choices mentioned above are all good solutions too.
My only other comment is to be a little careful about your placement of that temperature gauge probe in the outlet for the upper radiator hose. That will work as long as the thermostat is open, but may not read accurately if the tstat is closed OR if it's failed shut and risking engine overheat. It's probably close enough to the main cylinder head water passages that it will always give you some useful information. But personally I would be more confident in its readings if it had its probe located in a coolant passage that sees constant flow regardless of thermostat position, such as the heater circuit (provided you don't have a heater control valve), oil cooler circuit if you had one, etc. The late D24T engines had it located in the return from the cold start thermostat circuit. You could build a small diameter bypass from the upper radiator hose outlet to mimic that setup, even though your IP doesn't have that feature (and won't need it with direct injection).
Cheers!
Here's an example of the oil-to-coolant exchanger I would probably give strong consideration to. This one is listed as an upgrade for modified 4-cylinder TDI engines. For a 5-cylinder M-TDI I imagine it would work well. Could always install a sending unit and gauge to monitor oil temps too.
Depending on the thickness of the redblock style oil-to-air sandwich plate, you might also need the corresponding longer nipple to install this on the oil filter mount if you were to end up going this route.
Part number 028117021E
Depending on the thickness of the redblock style oil-to-air sandwich plate, you might also need the corresponding longer nipple to install this on the oil filter mount if you were to end up going this route.
Part number 028117021E
Well thank you for the kind words, and thank you for the 760 sway bar advice, I didn't knew it. I think it could be findable but V6 are not so common here either.
Yes It's good I been advised on this oil cooling issue! I know about those TDI water/oil cooler exchanger and I have one or two in my stock of parts. I went to the original D24 oil/air cooler mostly for "plug & play" reasons, and if I can keep it that way I prefer. But I know @petiww chose the other option and I understand why now.
I think I'll first try to read the oil temp with a gauge and if it's okay I'll let it like that and keep an eye on it. If it's not okay I'll see...
Do you think it's dangerous to drive that thing since I don't know about the oil temp yet?
About water temp sensor, I don't know if I understand well your point of view. To me it works great that way, it is the original position on a D24 and on a AAT/AEL engine for temp sensor, at it seems to work well in every situation. But maybe you're right, I know that on the 1.9tdi A6 C4 it was located on a heater hose. But I do have a heater control valve...
Anyway, engine bay is almost finished. I fixed a few last annoying details.
I had to buy a new alternator pulley since my alternator come from a 850, and pulleys were smaller at the times. now I have a full V70II setup, with a tight serpentine belt, and bigger pulley will help for more accurate RPM signal on cluster.
I bought a 90° elbow for upper cooling hoses, hoses come from and audi 80 I think.
And head to heater hose interfered with the shed so I had to buy a short silicon reduction elbow (22mm to 16mm IIRC) and a 16mm junction to fit the original heater hose.
Still have to connect the breather to the air intake, I have to find an aesthetic and practical solution for it. For now it is just pointed on the floor...
Yes It's good I been advised on this oil cooling issue! I know about those TDI water/oil cooler exchanger and I have one or two in my stock of parts. I went to the original D24 oil/air cooler mostly for "plug & play" reasons, and if I can keep it that way I prefer. But I know @petiww chose the other option and I understand why now.
I think I'll first try to read the oil temp with a gauge and if it's okay I'll let it like that and keep an eye on it. If it's not okay I'll see...
Do you think it's dangerous to drive that thing since I don't know about the oil temp yet?
About water temp sensor, I don't know if I understand well your point of view. To me it works great that way, it is the original position on a D24 and on a AAT/AEL engine for temp sensor, at it seems to work well in every situation. But maybe you're right, I know that on the 1.9tdi A6 C4 it was located on a heater hose. But I do have a heater control valve...
Anyway, engine bay is almost finished. I fixed a few last annoying details.
I had to buy a new alternator pulley since my alternator come from a 850, and pulleys were smaller at the times. now I have a full V70II setup, with a tight serpentine belt, and bigger pulley will help for more accurate RPM signal on cluster.
I bought a 90° elbow for upper cooling hoses, hoses come from and audi 80 I think.
And head to heater hose interfered with the shed so I had to buy a short silicon reduction elbow (22mm to 16mm IIRC) and a 16mm junction to fit the original heater hose.
Still have to connect the breather to the air intake, I have to find an aesthetic and practical solution for it. For now it is just pointed on the floor...