Hi all,

I have a 96 850R wagon that I just bought that has a coolant leak at this lower fitting on the passenger side at the bottom of the radiator. It seems to be an engine oil line that removed easily once I pried the collar open.

So I see oil coming out the center where the line with the 0-ring was but there is antifreeze seeping out around the threads. It generally leaves a puddle when it sits but isn't losing much coolant.

Can someone tell me the procedure for removal before I put a socket on it and ruin a new radiator by trying to remove it wrong? It sure looks like there must be two sets of threads -inner for oil and outer for antifreeze but I can't see in the hole without removing the radiator.

Pic attached, many thanks.

The previous owner had been sold a new radiator some months ago so I'm sure the shop created the leak. Maybe they just forgot teflon tape?

 

The oil cooler is built into the end cap. On every radiator I've seen the "black" nut is permanently connected to the cooler and to the same nut above it. It is one piece and it is one piece with the endcap. If you try to tighten or loosen that black nut you will ruin the radiator. The brass fitting should unscrew from the black nut but you want to make sure you are holding the black nut stationary and the brass fitting is doing all the moving.
If you're leaking coolant it has to be coming from the joint between the black nut and the radiator and it should be covered under warranty if it's a new radiator. You can't turn the black nut to tighten it as it's built solidly into the endcap of the radiator. There isn't any way to use Teflon tape or anything else other than to maybe slap a gob of epoxy on it.

 

Thanks loads. The leak is coming from between the brass fitting and the black nut.
If I hold the black nut from moving I should be able to unscrew the brass one from it and put some teflon tape on the threads to cure it then, right?

 

If the leak is coming from where you describe, that means it would be mixing with oil, and you wouldn't be leaking coolant alone. Also you would have major engine problems.

It seems much more likely that it only appears this way, and as Frogs said, the coolant is coming from around the black nut and the radiator will have to be replaced.

 

Update: Stranger things have happened...
When I put a wrench on the black nut to secure it,it was already loose -as in turning with my fingers. I spun it counter clockwise out against the brass hex and exposed a washer that it trapped against the tank along with a bunch of brass threads that went through a larger hole in the tank wall that the black nut and washer covers up and seals. I shrugged and turned the black nut clockwise and tightened it more to crush the washer against the tank. This caused more brass threads to stick out than previously, so I know it is tighter against the tank than it was. The brass one never did turn and I pulled on it as hard as was prudent with a foot-long wrench.
Perhaps I was mistaken and the leak WAS between the black nut and tank. I'll report back after I get the suspension back together and test it.

 

If it's still under warranty and most have a lifetime you would be much better off just replacing it now before you're out somewhere and the joint blows out. I cringe just hearing you mention "more threads" as it sounds like the fitting is pulling through the radiator endcap. Maybe not, maybe you've tightened it and won't have a leak but it doesn't sound good.

 

Runs great-no leaks. The slow drip from that point when it sat is cured. The previous owner had the radiator installed and gave me nothing for paperwork. He gave me the shop name and said they would have all the records. Not really interested in asking them anything. They diagnosed his slow coolant loss after replacing the radiator, water pump and hoses as a head gasket leaking into the oil so he sold it to me.
After an oil change and running it some I see no evidence of a head gasket leak, just a slow loss of coolant and condensation in the dipstick tube that makes it look like water in the oil. I'm in a pretty nice 850R for not much money now. I just put axles, 1 wheel bearing and upper spring mounts in it. The rack leaks a little so I powerwashed it and will be looking for the leak in it next. The same shop told him he needed to put a rack in it so I'm skeptical.

When I say more threads I mean it now matches the other 3 lines. before it had 1-11/2 threads showing outside the black nut, now it has about 4 like the others do.