BLUF: Has anyone changed the engine coolant temperature sensor on their R53? It seems super stiff to screw in, so much so that I'm worried I'll damage the threads on the cylinder head. How hard should it be?

DETAIL: I broke the connector casing on mine and removed the sensor. It was *really* hard to get out: both hard to access (had to get a special deep socket) and took a *lot* of force to crack it before I could unscrew the thing. But, eventually, out it came. My issue comes in trying to install a replacement. It's a pretty standard part, can be had for $20 at Autozone or O'Reilly's. But the new one only seems to screw in about half the threads before it gets to be really quite difficult to turn, to the point where I'm worried about stripping the threads on the cylinder head. The new ECT does have a rubber sort of coating on the threads to prevent leakage, so it makes sense that it's stiff but I'm just really concerned about damaging the cylinder head that I haven't had the courage to screw the thing in fully. I removed the new unit and bought yet another because the rubber thread coating was removed by my efforts.

 

I’ve left mine alone - it is in a tight place. You might need to remove thermostat housing to get clear sight - I don’t think it is ‘required’ to do it, but it is a blind job.

 

Yeah, sadly I don't have that option. The one I had was busted. I can get to it with a long 19mm socket. It's more that I don't have a feel for how tight it should be when it goes on.

 

Can you tell from the new one that you took back out, how much engaged? How much thread sealant was in contact? I think if 2/3 of the thread is engaged in the head, you should be ok

 

chase (harbor fright has a good kit) the threads and go with the new sensor

 

Maybe about 3/4 of the threads went in. At least, that's the amount of the rubber stuff on the sensor that was missing when I took it back out.

 

That's a good idea. I had to ask chatGPT what chasing a thread meant! Looking for the kit on Harbor Freight now. They only seem to have tap and die sets. I'll post a link here for posterity when I find it.

 

Using the proper "tap" / thread pitch is equivalent to "chasing the threads"
Use care.

Best of luck.

 

Go to a good auto part store - find a nut that is the same thread pitch - test fit with the new sensor, then practice with a tap. There will be a bit of metal that comes off, and will fall into the head. This is in the water jacket, so it should not be an issue.

 

I ended up getting this kit: https://www.harborfreight.com/carbon...ece-62832.html

Still to do the work yet. Fingers crossed!

 

I' have the same tap & die kit. It will work just fine.

 

i have to disagree on that one. with the tap and die, you're going to remove material. thread repairs don't cut. they aren't even sharp.

OP, you can probably get a "thread repair" kit from your local parts store as a free rental. i know the ones around me have them.

 

I think thats the one I bought as well

 

this looks like a good option. Maybe better. I've not tried it

 

$22 on amazon. just need to verify the thread pitch

 

that link isn't working for me, but there are a ton available on amazon straight outta china. i also work on some old american cars, so i need both metric and SAE. i'm pretty sure the kit that i have is kastar/lang 971. but really, my point was to use a thread repair vs tap. selecting the brand ... i'll leave that to you.

https://www.zoro.com/lang-tools-frac...B&gclsrc=aw.ds