Coolant loss

[deafen]

I've recently started losing an amazing amount of coolant -- 1/2 gallon (2 litres) or more per day. It's not going into the oil, and it's not leaking onto the ground when parked. Obviously, this makes driving a bit of an adventure; if I drive for too long, I start overheating as I lose coolant.

In another thread, I saw it mentioned that a bad radiator cap could allow the coolant to boil, causing coolant loss. If this is the case, would I see steam from under the hood at highway speeds? Would the temp gauge have to read higher than the 212 deg. line?

[Left Coast]

Hi, new member...but an old driver. I've recently joined this exclusive group after coming into a very nice '72 250C.

With respect to your coolant problem, if it is not going into the oil, not leaking out when parked, and not steaming up the passenger compartment, it probably is leaking out while you drive. Water pump failures will do that. Could be a hose too, or the radiator. Since I've always driven "vintage" vehicles, I've had the opportunity to see all of the above. There should be plenty of moisture around the engine under the hood, although I once had a radiator leak on the front side. Looked like the car was peeing onto the ground when I noticed it after a 30 mile drive. Not likely that you are boiling off a half gallon and not seeing steam, and yes temp would have to be higher than 212. Boiling point of coolant under pressure should be somewhere near 240.

HTH

[deafen]

Looks like it's the radiator. When the engine is running, it's got a drip at the top seam. Guess I'll try some bars-leak, and then off to the radiator shop if that doesn't work.

[230/8]

Deafen:

I would not advise Bars Leak. It works well in the newer air/mix style of heater systems that do not have water valves in the system. Hot water continuously circulates in these systems and temps are varied by mixing cold air and hot air. Our MBs actually have a water valve which controsl the coolant flow through the heater core. The Bars Leak can plug the valve. This will create more problems for you.

Just loosen the radiator cap to reduce system pressure. This may keep coolant from ejecting past the radiator seam. A radiator shop should be able to repair a leaking tank seam so long as the radiator/tank combo is still in reasonable shape.

230/8

[leenart]

If your up to it, get a torch and repair it yourself. Pull the radiator, wirebrush the leak and then solder the leak. I wouldn't use any of those repair kits you pour into the radiator or any other fillport. I have done repairs to my radiator by soldering and never had it fail

[Tomguy]

I MANUALLY repaired the leak on my old radiator, and it held amazingly well until the rad just cracked. Using a blowtorch, solder, and flux.

DO NOT USE STOP LEAK PRODUCTS. It WILL clog the heater core and valves. I took an AMAZINGLY LARGE amount of it out of my heater valves and core. It will make your car worse! Either repair the rad, or have a professional do it. You don't want to plug your heater valves.

[mzsmbs]

must agree with everyone here.. don't put that crap in there.. at best use pepper but i'd just try to get the rad fixed asap..

[deafen]

Okay, I hear you loud and clear. Unfortunately, I already put about a 1/3 dose of Bar's Leaks in before I read your replies! I had a little sitting around and figured it couldn't hurt.

I think it helped some, because I didn't lose near as much coolant today. With any luck, I haven't done any permanent damage.

I have a torch setup that I use for sweating copper plumbing; is that going to be hot enough for this kind of soldering?

[mzsmbs]

shoud be fine..

[Tomguy]

Originally Posted by deafen

Okay, I hear you loud and clear. Unfortunately, I already put about a 1/3 dose of Bar's Leaks in before I read your replies! I had a little sitting around and figured it couldn't hurt.

I think it helped some, because I didn't lose near as much coolant today. With any luck, I haven't done any permanent damage.

I have a torch setup that I use for sweating copper plumbing; is that going to be hot enough for this kind of soldering?

It was for me. What I did was I redid the ENTIRE top seam. Once I started soldering, the further I went along, the more I noticed the whole old seam was bad.

Take all the old solder from the seam out (torch + solder sucker or just a metal tube and lung pressure ). Wire-brush and sand any paint or corrosion out of the way, if needed. Clean it well with acetone. Then apply a generous amount of flux and solder as you go along, heating the metal (not the solder), allow the solder to flow into the seam. It will use a lot of solder (1/2 to 3/4 of a roll). When done, do a leak test, locate any leaks and resolder those areas.

[230/8]

You will need to use a tip that gives you the smallest and most concentrated flame. You want the heat at the seam, not on the tank top or the core where the tubes are soldered to the tank header. You could loosen the tube joints and create many more leaks if you are not very careful. Easy does it...

230/8