New replacement thermal bulb for AAV available

(John) #21

Almost there… will try to assemble the AAV today and will do some benchtesting.

(Aristides Balanos) #22

Looks nice John!

An extra idea:
When I rebuild my AAV, albeit with a normal 50° thermostat, I’ve put a screw and spring on the plunger so it could be very easily adjusted.
I also made a conical recess at the bottom of the screw so the pointy shaft would stay in place.
Worked very well.





(John) #23

Great idea! Although I might be a bit worried about the bolt and spring flying into the intake… did you fabricate new piston or reused the old one?

(Aristides Balanos) #24

It’s been there for more than ten years and it hasn’t move. The spring has to be quite hard though to insure that.
I reused the old piston, but fabricated and inserted the central part to give it some extra thread towards the inside of the piston for more adjustability (you can see it in the middle photo).


(John) #25

Finally finished assembling AAV!

Bench-tested AAV and al looks good. AAV fully close at ~65c.
Last step is to test in on the car.

(Paul M. Novak) #26

Very impressive. Well done. I hope it operates in the car as well as it looks.


(John) #27

Thans Paul! After all the effort I hope so too :)))

(John) #28

I have made few extra adapters so thermal bulb can be easily replaced with new replacement, so if anyone will dare to take on this project, I will be happy to supply the necessary parts :wink:

(chris gruchawka 1988 XJ-SC) #29

John, I’ll PM you.

(Wayne Canter) #30

I’m interested sending pm

(John) #31

Also made few extra cylinders for the valve as I managed to brake mine while pressing out…

Any air hole shape on the side can be milled out upon request :wink:

(John) #32

Just received one stuck AAV for rebuilding

Will take a lot of pictures during rebuild and will make a separate thread with detailed write-up :wink:

(Tom Moore) #33

Just tracked the Mercedes Benz number 001 203 95 75 (Bosch F026 T03 028) in Rock Auto. It appears they have the bulb unit for $16.50 USD Its a MAHLE/CLEVITE. TX10330.

(Robert King) #34

I am interested also- how are you sealing the bulb? How much are you thinking?

(John) #35

I’m using some sealant and o-ring. Here are some pictures:

(Robert King) #36

I am sure that is more than sufficient; I admire your workmanship.

(John) #37

Another small upgrade for AAV. Stainless steel piston.
Old vs. New:

(Dr.Quail/ Jon Wallace) #38

Was supplying new thermal motors with my AAV reman service a couple of years ago, SNG Barrat now supplies newly manufactured units here in the states.(Mfg. In Germany fits all V12 engines just slight different warm up patterns for different engine ECU maps) …so…
You don’t have to be so destructive to the units in disassembly if you are diplomatic…all removed pieces are easily reused if politely disassembled. Best, JW

(John) #39

I know and I don’t have such intention to be destructive :wink: My only goal is to improve and make parts better when I rebuild them :wink:
I know that new AAV is available, but with a price tag of 200-300eur I’m still in favour of rebuilding my old one :wink:

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #40

Nice! Any thoughts on coatings or linings to help keep this piston slippery in the cylinder?