: Has anyone ever replaced freeze plugs Before?



Caddy75
04-24-09, 09:01 PM
Hello everybody, while my '76 FWB was gettng its 6 monthly safety inspection the garage found that there is a corroded freeze/expansion plug near the starter,and traces of coolant could be seen dripping from the starter. Apparently this plug could blow out at any moment which would result in all the coolant escaping. So the starter motor has to be removed and the plug replaced. I've searched the forum and other websites but I seem to keep finding conflicting info on the diameter of these plugs,does anyone know waht the correct diameter is for this freeze plug by the starter

Also given that my engine has been losing coolant at a very slow rate (I filled it to the full mark on JAN1 and now its still slightly above the ADD mark when cold) surely this would be the only plug to be leaking? I understand that there are plugs at the back of the engine and that the whole engine would have to be removed just to get at those ones?
What I also don;t get is how this could become such a problem in just 6 months, I';ve done 1500 miles in that time and its always garaged and has usually been driven when its been a warm day

jayoldschool
04-24-09, 09:20 PM
I have never heard of a freeze plug blowing out. Has anyone else?

Three options:
- clean the area around that plug and try to use sealer on it
- use some Bar's Leak Seal
- knock out that plug and put in a new one

You don't have to take out the engine to do the rear plugs, but you do have to drop the trans and take the flexplate off. I wouldn't worry about it if they are not leaking. You can check by taking off the inspection cover on the trans...

dirt_cheap_fleetwood
04-24-09, 09:36 PM
You can knock out the plug and replace it with a new one or you can replace it with an electric engine block heater for ultimate cold weather starting ability. :)

cadillac_al
04-25-09, 08:44 AM
The freeze plug may not "blow out" but if it is rusted it could get a severe leak at any time. I seem to remember somebody posting that they had a vey hard time finding freeze plugs for the 500 Caddy and I couldn't understand why. It should be a common size but who knows. You can't ignore it though.

01devilledts
04-25-09, 01:32 PM
when I got my 68 SDV home after I purchased it, I noticed that the rear freeze plug on the passenger side was missing, the auto parts store had an assortment of metric and standard size brass and galvanized steel ones. so I measured the hole and went an picked up a brass one for like $1.38 or something like that. Cleaned up the surface of the block where the new plug would go into, put some black RTV silicone on there, found a socket that was just a tiny bit smaller than the plug and then hammered the plug back in. After that I haven't had any problems since.

VortecCaddy
04-25-09, 02:26 PM
Just replace the plug. Not sure how much room you have to get to it but I dont see it being to had of a job.

Caddy75
05-03-09, 03:52 PM
Well I've just replaced the plug. Fortunately only plug was corroded, I could see 3 on each side of the block, and there appear to be none at the rear of the engine, ar at least no apparent coolant leaks at the back or from the bellhousing. Replacing the one plug appears to have solved the problem. For those who want to knowe the size of freeze plugs on a '76 FWB they are 1 3/4 inches diameter.