JTD 16V mjet EGR cleaning and thermostat replacement - Alfa Romeo Forum
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(Post Link) post #1 of 4 Old 03-06-08 Thread Starter
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JTD 16V mjet EGR cleaning and thermostat replacement

Hi guys,

Everyone with more than 100K Kms, JTDs... I feel your pain.

Search for "Hi alfistas", where I got my EGR fully out and cleaned it.
I was happy with a job well done, but my thermostat needed attention, and I knew that much soot didn't end at the EGR...

Yesterday, after the EGR cleaning, I got to words with the chief of an ALFA stealer. He told me to get the tools and back in, because the EGR stuck was half my problem... and anyway, I had to fit the new thermostat, so in I went.

Summary: take as much of the intake as you can, clean all up, get the thermo out... return home, reverse trip.

Sordid details:
Disconnect the inlet pipe over the battery.
Get rid of the battery (needed for going after the termo, and eases a lot of the rest). There's a 13 nut at the left of it, remove it, disconnect the minus (black, on the front) and isolate it, remove two screws in the upper fuse box, disconnect the plus terminal, out with the fuse box. Push the battery over the frontal fuse box (it's by a hair but it comes out).
Go to block's intake area.
Unscrew 3 allens to take out the first metal bend on the intake body (most likely you'll need pursuasion, but mind the butterfly). Now you'll be seeing a butterfly valve... Free one plastic support on the first metal bend (pliars job). Save it, clean it.
Unscrew another 3 allens (different size from the firsts) to take the butterfly body. I didn't try to disconnect the vacumm pipe (couldn't figure how, didn't need to remove it to work the piece).

Now you'll be shocked: In just under 2hours, I removed some 3 or 4 soup-spoons worth of oily soot! Some from the first bent, some from the butterfly, most from the first 4 centimeters in the block's intake.
The actual EGR intake was almost completely blocked, and there's a design explanation to it. ALFA guys didn't want to disrupte flow in a big way, so they forged two passes distributing the outlet gasses of the EGR in 2 opposite spots around the intake diameter... these passings are hollow channels in the block's intake (some 15mm inward), and they get a wall from the butterfly body (when attached).
With a 1cm tip screw-driver (so, a biggy) I spooned out loads of crud from here... it's evident that the EGR was not properly flowing, nor the engine burning right (due to thermo). Because the butterfly-body forms one of the channel walls I didn't spot the structure immedeately... only by spooning out the soot did the channels became apparent, and finally figured out how the EGR outlet gets into the intake (when I cleaned the EGR yesterday I was puzzled with some sort of maze... the channels).

That done, leave it hanging, go for the Thermo. Mine cost 100, plus three braces to replace the factory single-use.

Now, let's keep the floor as clean as possible ok? Get a bucket, and if at hand, a 1.5m flexible pipe of some 40mm (... e.g. a 40mm red tube used for protecting hot-water plex). Pass the flex-pipe from below the car, up she goes to near the thermo. Place the other end in the bucket...
The first tube I went for was the one that comes from the thermo, points back, then down to the exaust cooler pipe (lateral to the block). Get cloth to get the few ml from the thermo itself, but the big flow comes from this pipe that goes in the exaust-cooler. That one gave me ~1.5 to 2liters of paraflu (refrigerant liquid). Into the flex it goes... don't waste it.
Now, same op on the pipe from the radiator... another 200-400ml. Unfortunelety I forgot something because I still spilled some 100ml when the actual thermo came out the block... try "milking" the other radiator pipe (that goes into the water pump, the other side of block), and open the cap on the deposit (left wing).
Finally release the electrical temp-sensor plug (get it??? mess with the paraflu, when that's under control, mess with plugs...).
Take a 13mm screw from back-bottom of the thermo, at an awkard 45... it's holding a stand for a tube and wiring. The stand is blocking the actual thermo bolts.
At back-top, use the tube-tool or extender, in between the temp sensor and the main-pipe out, there's a 13m bolt to the block. Same at front-bottom, just below the radiator-in pipe. Behold a ****ed-up thermostat in your hand. Continuing, release the return-pipe on the thermo (The little one that goes up the block, in the deposit).

Fit the pipes with new braces onto the new thermo, make a cloth pass on the block's face, hand-screw the 13mm holding the thermo. Make a pass at all the braces, final-fit the 13mm on the thermo.

Return home: mount the awkard-angle stand on the thermo, mount the intake butterfly (mind the metal sealing), mount the bend (mind the metal sealing), get the battery in (connect the plus first (back)) , attach the stand of tubes and wiring on the proper holes, put the intake pipe back into the inlet.
Coffe-filter a funil and get the bucket of paraflu in again.

That's almost done... now the testing.
Ignition, wait 20 to 30 minutes idling, don't freak out with some vapour coming up the front, it's just paraflu evaporating from the turbo housing and the exaust recirculation piping... it'll take a while.
Get your fingers under all thermo pipes to make sure there's no drip.
Get engine temp to 80 (just idling with hood open and no cover, it's normal it will not get to full 90). No drips? hurray, put the engine cover in, go for a 10 min spin, see that the temp goes little past 90, then back to 80-85. Check for drips again.

Hurray, you saved 1h30 to 2h of service at ALFA stealer!
I can't say I recommend to everyone, but you don't really need to be extremely crafty either... It's a 3 out of 5 (a 5 is like changing valve seals and get it all back in again).

See you guys!
jpinto3912 is offline  
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Re: JTD 16V mjet EGR cleaning and thermostat replacement

Hi guys,

If the JTD is the same engine as the 1.9CDTI in the astra this maybe useful

How To: Clean EGR Valve 1.9 CDTi - Astra Sport and Astra Owners Club Forum

Astraman is offline  
(Post Link) post #3 of 4 Old 04-06-08 Thread Starter
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Re: JTD 16V mjet EGR cleaning and thermostat replacement

Yes, pics always help...

My word of advise is that cleaning the EGR is not a complete service... By the time the EGR gets stuck it's because huge build-ups are already clogging the EGR->intake passages.
And if all that is hapenning, it's likely due to cold-engine burning (a thermo stuck open), or a bad MAF telling "big flow" all the time.

Meaning, on the long-run you'll save $ or £ or € in gas and parts if you take out the complete intake+egr+thermo and fix it for the next 80Kmi (~130K Kms).
If you're still smoking, even when water is 90º, ask a shop to check real-time errors related to the MAF.

See you!

Last edited by jpinto3912; 05-06-08 at 08:46.
jpinto3912 is offline  
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Originally Posted by Astraman View Post
Hi guys,

If the JTD is the same engine as the 1.9CDTI in the astra this maybe useful

How To: Clean EGR Valve 1.9 CDTi - Astra Sport and Astra Owners Club Forum

Useful info, I am going to give mine a clean
Andrew Lusso is offline  

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16v , cleaning , egr , jtd , mjet , replacement , thermostat

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