Temperature sensors leaking

[Mike92STX]

I have a aluminum thermostat housing and I noticed coolant on the housing. I thought the bypass hose was bad, so I just replaced that and now it looks like the sensors are leaking. The housing is only a few months old so I'm wondering is there a fix or do I have to replace the sensors?

 

[sgtsandman]

I’m pretty sure they have an o-ring.

Replacing the o-ring should fix the problem. Look at the hole the sensor goes into and make sure it’s smooth. All it takes is a piece of dirt or a hair to cause a leak. So, even a scratch can cause a leak.

 

[Mike92STX]

I was trying to decide if I should replace O rings or the sensor. As I mentioned the whole housing is only about 4 months old. I was trying to figure out if there is a difference in the sensors. They are both the same color and because they came with the housing, I didn't look that close at them before it was installed. I'm also wondering if the O rings a special or can I put one from some that I have as long as they fit tight enough?
Thanks for your help.

 

[RonD]

Most likely O-rings but check rad cap, I think they were 16psi caps
If cap is holding 20psi you can get leaks

 

[sgtsandman]

I was trying to decide if I should replace O rings or the sensor. As I mentioned the whole housing is only about 4 months old. I was trying to figure out if there is a difference in the sensors. They are both the same color and because they came with the housing, I didn't look that close at them before it was installed. I'm also wondering if the O rings a special or can I put one from some that I have as long as they fit tight enough?
Thanks for your help.

I’m not sure on the sensors. Mine only has one and I reused it. Even though the housing is relatively new, the sensor could have been around a while when they put the kit together and the o-ring hardened up due to age and not being exposed to something to keep the rubber pliable.

I’ve also seen new o-rings with defects even though the rubber itself was in serviceable condition.

As far as just replacing the o-ring or the whole sensor, that will depend on cost and availability. How much is just the o-ring going to cost and is it readily available? If it’s only $0.10 but will take 3 months to get, a whole sensor with a new o-ring would make more sense even though it would cost more.

 

[Mike92STX]

I just looked at some O rings I have and the ones I have don't seem as thick as the ones on the sensor. I happen to have a couple of sensors I kept from the first time I changed the thermostat. I'm going to the local hardware store to see if they have some that are a better fit.
Ron, the radiator cap has a 11 stamped in the center, I'm assuming that is the PSI limit. Seems a little low to me. The radiator is new, and it came with the radiator.

 

[RonD]

Yes, 11psi would be wrong, but that's probably not what that 11 means, unless it has "psi" after it
14psi to 16psi are what most rad caps use on overflow systems
Degas systems can be different

If its 1.1 then that means about 15psi, which would be correct
This can mean metric or "bar" pressure so caps using this 1.1 can be sold world wide, and people know what it means, in the US we tend to use PSI

 

[Mike92STX]

Wow, I thought I saw a dot between the 1s, but I figured it was just a spot from manufacturing. As usual you are probably correct. I'll look closer in a little while when I replace the O rings.

 

[Mike92STX]

I finished it about 1 1/2 hours ago. When I started it up to check for leaks there was coolant gushing out around 1 of the sensors, so I shut the engine off and checked, I had not gotten the clip in right the sensor had come up, so the clip was underneath it. I corrected the error and tried to clean up some of the coolant, while it was running. It appears to not be leaking but I lost more coolant than I thought because when I moved the truck what I thought was melted snow had some coolant in it. Have to by some more coolant tomorrow and fill it and check for any leaks again.
Thanks again for the suggestions and help.

 

[DILLARD000]

For the ClipMounted TempSensors, have found OffBrand\NonOEM ones
often have cheap thinner springwire Clips compared to MotorCraft, that do not hold as tight.
Gotten in the habit of using a smear of RTV around the ORing\Threads on TempSesnors, to help prevent leaks.

 

[sgtsandman]

Yeah, those clips for the sensors can be a bit of a bugger to get in right. Glad you got the problem fixed.

 

[DILLARD000]

...looked at some O rings I have and the ones I have don't seem as thick as the ones on the sensor
...sensors I kept from the first time I changed the thermostat
...to the local hardware store to see if they have some that are a better fit
...cap has a 11 stamped in the center, I'm assuming that is the PSI limit. Seems a little low

Yep, cap rating stamp is 1.1 meaning BAR not PSI.
Every other country on the planet went metric 50yrs ago.
Common metric RadiatorCap ratings:
1.1bar = 16psi +\-2psi
1.2bar = 18psi +\-2psi
1.4bar = 20psi +\-2psi

 

[sgtsandman]

Yep, cap rating stamp is 1.1 meaning BAR not PSI.
Every other country on the planet went metric 50yrs ago.
Common metric RadiatorCap ratings:
1.1bar = 16psi +\-2psi
1.2bar = 18psi +\-2psi
1.4bar = 20psi +\-2psi

Funny thing is, not for everything. At least the Aussies still use psi for tires instead of Bar.

 

[DILLARD000]

Chaos rules!

 

[Jazzer]

Don’t get me started about Imperial Gallons……