How To Rebuild a Heater Valve

I have gone through a few heater valves. guts break, replace whole valve with another used valve, repeat. enough.

this time i bought a rebuild kit from BLUNTTECH. why buy a new valve when the brass part does not wear out, the kit includes EVERYTHING but the brass shell. rebuild is a VERY simple process.

so what do you need for this job?

old valve

rebuild kit

flat blade screwdriver

phillips head screw driver

7mm wrench

small pick

brass cleaner

dremel with wire wheel

NOTE - this is just the rebuild of the later "big" heater valves and does not include the removal or install of a valve.

the kit and the broken valve


remove two screw with flat blade, take cover off.



now use 7mm wrench to unbolt control arm from back


remove broken guts


old and new guts. new looks much stronger.


very important part here. main reason these valve fail (at least from all the ones i have taken apart) is that the inside of the valve corrodes in one spot becoming rough. particulary true if the valve sits in one open or closed position for a long time. the plastic guts then hang up on the corroded area of the shell and break.

clean the inside of the brass shell until nice smooth and shiny. i used some 600grit and a dremel wire wheel to do this, then polished with metal polish like ibis or brasso.


now assemble the guts



don't forget the o-ring on shaft


i used a little teflon grease on all the parts.





now grab the cover. remove old o-ring with pick


same cleaning and polish rule applies to cover


install new o-ring


okay now put cover on the valve. note the position and alignment of the guts and the arrow on the cover.


use the new screws and lock rings to assemble (new parts are phillips heads)


put the control arm back on with 7mm wrench. don't forget the little washer.


note position of arm and open/closed valve. we are looking at the HEATER end of the valve in these picks.





DONE! :)

bagged up and ready for install at a later date.


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Thanks for your latest two articles.  Although I am not in need of either at the moment, I appreciate the effort, attention to detail, and article/photo quality.  I am sure I will need these some day.  My only constructive criticism... too clean.  You make my car feel dirty.  Lay it off would ya?

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Great help! do you have a part number for the rebuild kit?  I've tried to look it up on BLUNTTECH and cant find it.



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When I rebuilt my heater valves using this kit, I replaced the seals with different ones:


I ordered the new seals from:


I ordered seals made of V75 Viton after reading about that material's properties on the store's website.


The small seal is 2mm x 8mm V75 Viton O-ring Black  Model: V2.00X008 -- (2mm thick, 8mm inner diameter)


The large seal is 1.5mm x 31mm V75 Viton O-ring Black Model: V1.50X31 -- (1.5mm thick, 31mm inner diameter)


I believe that the smaller seal in the Blunt kit is 1mm x 8mm -- (1mm thick, 8mm inner diameter, not sure of the material it's made of)

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