Changeing water temp sensor question

[flathead 39]

Engine is 8ba in a 39 deluxe. I'm changing over to electronic gauges and need to change out the water temp sensor. Do I need to drain the radiator? Thanks.

[Zeke5180]

Flathead,

In my 37 when I changed to the electronic gauges, I drained the radiator otherwise you'll have antifreeze coming out once you remove the old sensor. I had just loosened the sensor and the antifreeze started leaking out. My upper hose runs to the center of the head with the temp sensor just next to that. Not sure of the arrangement on the 8ba.

How's the installation on the new gauges going?

John

John

[Mart]

You need to drain it enough for the coolant level to be below the sensor opening. You don't need to drain it all. Knowing when you've taken enough out is the trick.

[big job]

I have never drained it have everything ready remove with one hand replace with the other hand so your fingers get wet and the coolant loss is 'paper towels' I do it all the
time.....

[19Fordy]

It takes very little effort to drain the rad level below the sensor level and doesn't
ruin your day if something goes wrong with the install.

[flathead 39]

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Thanks for the info.. I was hoping not to have to drain it..

Originally Posted by Zeke5180

..

How's the installation on the new gauges going?

John

John

It's been a challenge but the only real problem was mounting the oil pressure gauge, photo to follow..

[flathead 39]

Originally Posted by big job

I have never drained it have everything ready remove with one hand replace with the other hand so your fingers get wet and the coolant loss is 'paper towels' I do it all the
time.....

...Except if you have a hand full of adapters for the new sensor and it will take 2 of them to fit and you wont have a clue as to which ones you need until you remove the old one. Yea I considered that option too...

[flathead 39]

Spent more time on this thqan anything else..so far.

[Zeke5180]

Flathead,

Will that affect your oil pressure reading? Just wondering.

John

[fortyonerag]

I installed an aftermarket oil and temp gauge. What I found was the new temp sender unit was considerably smaller that the stock unit and after the adaptor around it, I'm not sure it even gets wet!

It will register only after the engine gets really warm - long after the stock guage is registering. I have checked the unit and it is working correctly, but I think the sensor is residing in an air bubble - its very short. I'm not running thermostats, so that might also be a factor.

I was thinking of mounting something on the electronic sensor to extend its reach, but I'm a bit leery that anything I fit onto it to extend its reach might fall into the water jacket.

[flatford8]

Seems to me there’d be some vibration way there..... maybe not...... Mark

[19Fordy]

When I installed the same oil pressure "piping" set up on my 8BA it did not effect the oil pressure reading.

[flathead 39]

Well, it shouldn't be long before I find out.?!

[aussie merc]

to fortyonerag if your worried about an air lock around the sender either back out the sender till a small amount of coolant appears or drain the coolant down till you can remove the sender then slowly top up till the coolant appears in the hole and then reassemble the sender into the engine

[fortyonerag]

^^^^^I'll try it out. Many thanks.

[flathead 39]

Me too, thanks!

[BobR35]

If it's not too late on this topic, I just installed two new temp gauges and did not drain the fluid. Had everything ready and put a finger over the hole in between the change. Lost a couple drops of fluid, that's all. Everything went well.

[big job]

Originally Posted by flathead 39

...Except if you have a hand full of adapters for the new sensor and it will take 2 of them to fit and you wont have a clue as to which ones you need until you remove the old one. Yea I considered that option too...

I should have said you need to know what size you need first its just a standard pipe tread. You can tell with just one look. I do it this way cause I never got along with drain pans for coolant or even oil.

[flathead 39]

Originally Posted by Zeke5180

Flathead,

Will that affect your oil pressure reading? Just wondering.

John

The pressure reading was good until.. climbing a 6% grade on the freeway I noticed the gauge read 0! After much scratching of the head & advice from all sides, including my son (a retired Merchant Marine Engineer) who suggested I use the tried & true nylon tube with a couple coils. Simple Huh?. Anyway finally made the change today and tested on a nearby mountain pass. No more problem.