When is a freeze plug not a freeze plug?
 

Hello all. I've got a 2002 T&C 3.8 leaking antifreeze from the back of the block. Looks similar to a freeze plug but has a sensor mounted in it. The temp sensor is up on the thermostat housing so what is this? And how do I fix it? I can wiggle it and see that it's loose. Any thoughts or ideas?
Tom

As you have an obvious leak, and the core-plug (that's what the UK calls them) is obviously loose, I would try the following which costs nothing. Forget putting anything in the coolant that claims to "seal leaks". Even the ones that work don't work for long.

Drain and save the coolant so it is below the level of the core/freeze plug. Wait until the area is dry, or help it along with a blowlamp/paint stripper gun.

When bone dry, scrape away as much of the crud around the plug's joint with a suitable tool like an old sharpened screwdriver. Then get the smallest wire brush and give it a good brushing to make a good surface.

Next procedure is split two ways --

1) Get some normal car body filler and fill the joint leaving it thick and proud, pressing it well into the joint. If you can leave it 24 hours, good. If you can't, gentle heat with a heat gun or hair dryer will accelerate the setting of the epoxy in the resin.

2) Go to a plumber and get some of the special "epoxy putty" they use to cure leaks around the home heating system etc. This stuff is special in that it is intended for "wet-repairs". When you get it, there are two 'columns' of stiffish putty that you have to knead together by hand. Your job will only require about one inch of each. Follow the instructions exactly here. This stuff is truly amazing -- I repaired a leaking hot water cylinder in my house with it well over a year ago, (there were dozens of pin-hole leaks around the electric heater boss) saving me many hundreds of pounds and having to demolish a wall to get the cylinder out. It's still working great.

Your cooling system pressurizes to about 15lbs. above atmospheric in a car, and the above stuff should stand that easily. But be fussy about doing a good careful job as outlined in the instructions. It cost me £2:50, that's around $3:50.

A cheap way out of the problem?

Leedsman.

p.s. Get a quote from a service station for a "normal" repair, deduct the 'plumbing way' of doing it -- then send me half the balance...lol.