Unforeseen consequence

[Robert Brennan]

TC 7794 EXU is nearing completion, now wearing new paint and (FTFU restored) proper bumpers, but in my attempt to achieve a better bonnet to cowling fit, I tightened the near-side stay bar without first removing, or at least loosening, the top radiator hose that connects to the flange on the bottom of the radiator shelf. After congratulating myself on the good fit of the bonnet, I noticed a small green puddle on the garage floor.
It seems that the hose cracked the radiator shelf flange, and I'm wondering how to fix it. I know the hose will have to come off; it is almost due for replacement, anyway. What I don't know is if the radiator has to come out to repair the crack, or if it can be properly repaired in place. Because you're working upside down, soldering looks tricky. Are there other products offering long term duration?
If the radiator is not removed, is it possible to install the top radiator hose? And if it is removed, what other parts can I expect to replace?
I always appreciate hearing from owners who share their solutions to the many questions I have had over the past years. You are a great resource.
Bob Brennan
S. Freeport, ME

[Gene Gillam]

Bite the bullet Bob, remove the radiator and have it checked and fixed properly. You can have it off in an hour and a good shop can have it back to you, cleaned, repaired and repainted in a couple more. You won't regret the time spent.

[Steve Simmons]

I agree, it's quite easy to remove and I prefer to fix it with solder than to dump aluminum powder in the entire cooling system. That stuff has to eventually deposit somewhere. Removing the bonnet is the hardest part of the job. Once it is removed and the radiator drained, the rest takes about ten minutes. To remove radiator...

• 1. Prep: Remove the bonnet, drain the radiator, and remove temp sensor (if installed).
  2. Remove the two nuts on the bottom of the radiator. Good time to replace the little rubber pads before reassembly.
  3. Remove the two bolts connecting the headlamps to the radiator
  4. Remove the two radiator stays. I like to completely remove them to avoid the stays flopping around.
  5. Pull the lower hose off the elbow. I like to keep it connected to the radiator, easier to reach the top clamp than the bottom one when removing and reinstalling the radiator.
  6. Loosen the top hose.
  7. Lift the radiator out, taking care not to hit the headlamps or paintwork on the apron. If the top hose is sticky, work it back and forth to break loose before pulling radiator.

As the Hanes manual says, "installation is the reverse of removal". I always refill with plain water for the road test, then put a splash of anti-freeze in once I know everything is working and leak-free. If you remove the grill shell (8 screws I believe), there may be some adjusting after reinstalling it.

Good luck!

[Robert Brennan]

Thanks to Bob Stein for his suggestion of ALUMASEAL- there were many happy customers on Amazon, but Sandy Sanders observation tipped the scales in favor of Gene Gillman's advice to "bite the bullet".
Ross's suggestion that its not too big a job to remove the radiator proved correct, especially with Steve Simmon's numbered steps. "Boiling out" proved impossible at the radiator shops I contacted in environmentally correct southern Maine. I had to settle for a "deep and prolonged" flush.
So tomorrow, I pick it up, soldered and cleaned- estimated repair cost of $150. It seemed like a good opportunity to order new hoses and "Jublilee" clamps from Doug Pelton as well as the new rubber at the bottom of the radiator that Steve suggested.
Thanks to everyone who inspired me to take on this new challenge.
Bob Brennan
S. Freeport, ME

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[Richard Michell]

Steve, could you explain why you add a "splash of antifreeze" to the radiator water. Thanks.

[Steve Simmons]

Anti-freeze has rust preventatives in it. Water transfers heat better than anti-freeze, but considering our engines are made of iron and need to last indefinitely, some rust prevention is a good idea. Anti-freeze is also a better lubricant than water for things like water pump shafts and seals. In general my TC doesn't see temperatures below about 20F, usually ranging from low 30's to about 110F. So I don't really need anything to prevent freezing, but I do like running about 10 percent (maybe up to 30 percent in some cars) anti-freeze.

[frenchblatter]

I've used soluble oil before now. Oil has anti-freeze properties, stops rust and lubricates water pumps.

[Richard Michell]

Thanks Steve. If you are adding the antifreeze for rust/corrosion protection then I don't think that a "splash" is enough. For a typical corrosion-inhibited antifreeze you need about a 25% treat rate to give protection. The inhibitor is consumed over time as it does its job and so suppliers typically recommend a minimum initial treat rate of about 33% for this function. The attached gives some info.

http://extension.usu.edu/files/publicat ... /FM-09.pdf

I live in a location where freeze protection is not needed and so I prefer to use just water plus an anti- rust/corrosion additive. When compared with water, antifreeze reduces heat transfer efficiency at the sort of concentrations that have to be used.

[Steve Simmons]

I used to run 70/30 but have found that a lower value works just as well in the TC. Most sources recommend flushing the cooling system each year. I do it fairly regularly on the TC, and over the past few years have run 10-20% with no signs of negative effects. I do also add a bit of Water Wetter to help with heat transfer. Tests on other cars have shown a very slight improvement in cooling (2-3 degrees on average).

[Richard Michell]

Thanks Steve. I guess I was rating "a splash" as less than the 10-20% range. Unlike modern engines, the XPAG does not have a lot of mixed metals, operating at high temperatures (such as alloy heads). It requires very little anti-corrosion help if soft water is used. So I would agree that you should see a good result.

However, if running a low level of antifreeze in the cooling system - presuming it is glycol based - I believe that regular changes are certainly wise. At temperature, some of the glycol oxidises and produces acidic compounds. These accelerate corrosion. The antifreeze contains pH buffers to fight this, as well as having anti-corrosion additives. But if the treat rate is low, the buffering and the anti-corrosion additives can get used up quite quickly (if you use your car regularly and the coolant sees high temperatures). Once this has happened, the presence of antifreeze can actually increase corrosion as it causes the pH of the water to drop.

[Duncan M]

Modern glycol based antifreeze (most are phosphate free also, now) as mentioned, is a very good water pump lubricant. It is banned in most racing events because it is also very slippery if leaked on the track.

Water wetter type product is used as a replacement for glycol based coolant in racing (at least in vintage racing on the left coast). Some people use it in their street cars, but I would not because of the lost lubrication qualities.

As long as glycol coolant/anti-freeze is changed now and then, I am not concerned with it causing corrosion.

[frenchblatter]

Soluble oil is cutting oil used with lathes. It mixes with water and turns into a white liquid.

I now use modern OAT coolant in the Caterham.

I'll used good old fashioned Bluecol type stuff in the TC and change it every year.

[Duncan M]

Apparently some OAT (organic acid technology) is designed for plastic radiators and eats lead solder if it allowed to stay in there too long.

[frenchblatter]

OAT, Organic Anti-freeze Technology (I think) will corrode old solder. The new solder, which is lead free is OK.

I'm not sure if I can get the older anti-freeze mix in France but as there are lots of old cars here I'm sure I will. The old cars are not collectors, they just run them forever.

[Richard Michell]

I agree with Duncan, the new OAT anticorrosion technology is not suited to our cars. Nor is it needed.

We are fortunate in Australia in that the relevant Australian Standard for coolants, AS 2108, covers two types- those that contain ethylene glycol (antifreeze) and those that do not. Its title is Engine coolants Type A and Type B for engine cooling systems. Type A is the glycols. The consequence is that the labelling on retail products is easier to decipher here.

I am also fortunate that I do not need to use antifreeze where I live. Hence I can use a Type B product, one that just gives corrosion protection.

If you have to use an antifreeze then, as has been suggested, the "older" formulations are more appropriate. Most suppliers have a range and the "bottom" product is probably the one. It will have a recommended service life of the order of 2-3 years. The Mobil UK site is on this link http://www.mobil-carcare.com/products/antifreeze and my suggestion would be their Antifreeze Concentrate (scroll down to find it, past the 200 litre drum).

A word of caution on the use of soluble oil (an oil plus an emulsifier additive). While great for the water pump bearing it attacks rubber hoses. That is why it is not generally marketed any more. Soluble cutting oil may be more problematic. Cutting oils contain sulfurized EP additives - more aggressive ones than are found in diff oils - and these could react with copper/brass/lead, etc. although only slowly at the temperatures involved.

[Steve Simmons]

Just for further data, I have two vehicles that cool by thermo-syphon. No need for anti-freeze or lubricants, just maximum cooling. In these I run pure water, sometimes with Water Wetter added. I've had no issues with rusting. I change the water every now and then and it comes out pretty clean.

[Norman Golm]

There is a good article concerning cooling in the technical resources section of the tabc forum "the hidden water passages" these two small holes if clogged will cause local boiling. I have drilled these out in the 4 TCs I have restored and have never had any cooling problems. Plus I put MGA phenolic spacers between the carbs and the intake manifold to preclude percolating of the fuel in the float bowls.