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Loctite on engine sensors?

dwranda

Well Known Member
I just received my sensor kit from Dynon and am wondering if the CHT sensors, oil temp sensor, Kavlico sensors, and I guess pretty much anything that threads onto the engine is OK to use loctite. I've used it on the steel fittings for oil lines but am wondering about sensors. Thanks!
 
If you’re talking about LocTite 565, then yes - you can use that on sensor pipe threads. If you’re talking about generic “LocTite” (blue, red, or green) to keep things from backing out - no, you don’t use that on pipe fittings. Van’s Section 5 (part 5.27) calls out Tite-Seal, Permatex #2, or LocTite 565. Make sure to use one of those and you’ll be good.
 
Thanks Paul. I've been using Loctite 567. That's fine right?

Looking at the specs on the LocTite web site, 567 looks better in regards to temperature than 565, with all other features pretty much the same, so unless there is some undocumented difference, I don't know why it wouldn’t be an allowable substitute.
 
I just received my sensor kit from Dynon and am wondering if the CHT sensors, oil temp sensor, Kavlico sensors, and I guess pretty much anything that threads onto the engine is OK to use loctite. I've used it on the steel fittings for oil lines but am wondering about sensors. Thanks!

You need to look at the Van’s firewall forward plans to see how the sensors should be mounted. The only sensor mounted directly to the engine is the oil temperature which has a straight thread with a crush seal and should be safety wired. The remaining sensors are supposed to be mounted to a firewall manifold connected to the engine with hoses. It’s a good idea to keep the pressure sensors isolated from engine vibration.

Skylor
 
However, there *are* parts of the sensor "assembly" that do get mounted on the engine for other things...the restrictor fittings or NPT fittings, etc., for MAP, Oil Pressure, Fuel Pressure. Same question probably applies to those. (I don't recall what I used, though...but 800 hours with no problems, knock on wood :) ).
 
However, there *are* parts of the sensor "assembly" that do get mounted on the engine for other things...the restrictor fittings or NPT fittings, etc., for MAP, Oil Pressure, Fuel Pressure. Same question probably applies to those. (I don't recall what I used, though...but 800 hours with no problems, knock on wood :) ).

For those, see post #2...

No thread-locking compound needed on pipe threads, only sealant.

The fuel pressure, oil pressure, and manifold pressure fittings at the engine should be Vans's pipe to AN restrictor fittings VA-128. This is a 45 degree fitting which can't unscrew itself if there is a hose attached!

Skylor
 
However, there *are* parts of the sensor "assembly" that do get mounted on the engine for other things...the restrictor fittings or NPT fittings, etc., for MAP, Oil Pressure, Fuel Pressure. Same question probably applies to those. (I don't recall what I used, though...but 800 hours with no problems, knock on wood :) ).

For those, see post #2...

No thread-locking compound needed on pipe threads, only sealant.

The fuel pressure, oil pressure, and manifold pressure fittings at the engine should be Vans's pipe to AN restrictor fittings VA-128. This is a 45 degree fitting which can't unscrew itself if there is a hose attached!

Skylor
 
You need to look at the Van’s firewall forward plans to see how the sensors should be mounted. The only sensor mounted directly to the engine is the oil temperature which has a straight thread with a crush seal and should be safety wired. The remaining sensors are supposed to be mounted to a firewall manifold connected to the engine with hoses. It’s a good idea to keep the pressure sensors isolated from engine vibration.

Skylor

I have the manifold where the kavlico sensors are connected to the engine with hoses. The sensors in the kit that got me thinking about this were the cht that screw in.
 
I have the manifold where the kavlico sensors are connected to the engine with hoses. The sensors in the kit that got me thinking about this were the cht that screw in.

For the CHT probe collars, nothing on the threads is needed except perhaps a touch of anti-seize compound. These are not safety critical and just don't seem to have an issue with loosening up.

SKylor
 
Nothing escapes from where the CHT probes go. If you only had one CHT, the other three cylinders would be fine, so there's no need to seal or lock those. I recently changed the bayonet adapters that came with my old Blue Mountain system for the non-bayonet probes that came with the G3X and was glad I had used anti-seize because a couple of them were a bit difficult to remove. The new probes are showing no inclination to move.
 
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