I have a small seeping coolant leak in my '75 L48 that appears to be coming from the thermostat housing housing gasket. My manual says to empty the coolant prior to replacing the thermostat but I'm wondering if I need to do that? Looks like I can just remove the hose and hold it up, remove the housing and replace the gasket - anybody in the know out there? thanks!

 

I know on my '73 coolant come out all over the intake when I replaced my thermostat. I'm going to be lowering the coolant level some as I'm getting ready to do it again because I put gasket sealer on it and that was not used originally and NCRS judges didn't like that so i'm fixing it.
I hope that helps.

Good luck

 

You only need to drain about 1/2 gallon of coolant to get the fluid level below the inlet housing. Just remove the radiator cap (or o'flow tank cap) and open the radiator petcock for a couple of minutes [or so]. You also need to put some Permatex #2 sealant on the threads of the inlet housing bolts so that they can't weep any coolant up the threads. If you have a chrome housing, use some 250 grit sandpaper to scuff-up the gasket surface a bit. You want a 'random' sanding pattern...don't just stroke the part over the sandpaper in one direction.

 

Thank-you! One more question - the last time I changed the coolant the drain **** separated from the rad and has been repaired with a somewhat permanent, un-openable fix. To drain some fluid would it be easier to undo the lower rad hose from the rad or siphon some coolant with a vacuum from the rad itself? Or is there a better method? I hadn't planned on having to drain coolant so soon ...

 

It would be easier to buy a $5 syphon pump (bulb operated) at a local parts store and 'suck' enough fluid out to reduce the fluid head height. The lower rad hose is a 'bugger' to get loose...and when you do, it will dump a lot of fluid.

 

Thanks a lot for the advice - i thought that looked a bit gnarly to get at!

 

Heck I can't even get to the screw on my lower rad hose to get a screwdriver in it, they must have put that thing together before they assembled the damn car

 

You aren't kidding!!!

 

Remove the heater hose at the water pump and enough coolant will drain to remove the T-Stat housing without making too much of a mess.