Heater valve studs leak

I do not think it is a function of the hoses or the clamps. but rather the hose nipples on the heater valve are corroded.

 

Difficult to solve as the water is seeping past the seal due to possible pitting of the metal on the hose connections (studs)

Try cleaning the metal surface with emery paper to good a good even finish, it worked for me but eventually I replaced the whole unit for concern over its eventual failure while out driving.

It will be a weakness in the cooling system so replace it, the upshot is peace of mind that hot water will not spill onto your leg at best or overheat at worst.

Tony

 

Putting Threebond or Hondabond on the fitting and then putting the hose on will solve your problems. I've done this a number of times with great success.

 

Good luck with the solution Peter. If it is just a slight leak I'm sure you will be fine.

Now for a story. A few weeks back I shared our setback in getting the trim for the door pocket. Today I'll tell you about our hose 'incident'.

We were working feverishly to finish the Dino in time for the 2014 FCA National Meet. The car was due to be at TFX Transport at 9 am the next morning for shipping to Virginia. Paul and I put in a full on race car inspired thrash that had us fully awake for over 30 hours leading up to our deadline. Approaching 9 am we are destroyed but the car is done. Luckily the TFX offices are about 1km from our place. With the car done we drove it and met our deadline.

Once there the guys at TFX told us that they were waiting on some other cars and that they would not need the car until about 1pm. Being so close we decided to take the Dino back to the shop and give it one last looking over before handing it off. After all we were so tired that any bit of a look would be valuable. I drove and Paul followed me back to the shop. As we were literally pulling into the driveway an almighty plume of white smoke shot out of the engine compartment. Paul immediately feared a catastrophic failure but I was a little calmer and, having blown up dozens of race engines over the years thought better and, just coasted the car to our garage door with smoke still billowing out of the engine bay.

Turns out the upper coolant hose to the thermostat housing just blew right off and sprayed boiling hot coolant over the entire engine. We now have just over 3 hours to get the car back to the shipping company and its perfect engine bay is now soaking wet with coolant and we are just dead tired. Where the energy came from I don't know but in a flash the car was on the hoist, engine cover, rear wheels, wheel arches, and airbox are off and we are cleaning at an Olympic pace. Problem is that coolant cannot just be wiped off. Wherever it touched leaved a dirty stain that had to be cleaned off with care. Believe me when I say coolant got EVERYWHERE but luckily nothing was physically damaged. It was all a blur but in the end we got it all cleaned and the car was delivered JUST in time.

So why did the coolant hose blow off? It was properly installed and tightened but the original Serflex hose clamp just could not put down enough clamping force to hold the hose in place. We had cleaned the surfaces with acetone to de-grease them. We had seen photos of cars in period with two hose clamps in this position which explained the problem not to be isolated to us. The solution came in a thin coating of Hondabond on the fitting followed by the Serflex clamp. Totally invisible it worked perfectly and now over 6K kilometers later it is still dry and securely fixed. I would recommend it to anyone struggling for that last bit of seal on a hose fitting.

 

Interesting story, luckily it happened on the driveway, had it been at 50mph then you would have done a lot more damage.

I don't know of any reason why anyone should / would put a "gasket" sealant onto a new hose connection with a brand new rubber hose and a good quality jubilee / Serflex clamp and secured tightly.

Is this a one all fix sealant or is there a multitude of different types of Hondabond?

I would recommend you check the technical specifications first as Nuvolari's experience is a timely reminder how things can go belly up very quickly.

Tony

 

Well to be perfectly accurate it happened on the road just as I was about to turn left on the driveway so I was moving at an ok pace when it happened thereby making a huge mess. Luckily it was so close to our shop that I just shut the engine off and coasted it in without the engine temperature even moving.

That said I do agree with you that additional sealant should not be necessary in a proper assembly but believe me when I tell you that everything was new and surgically clean. Had we had the option of a newer hose clamp (remember we were after concours correct) that applied more force then there would be no problem. Who knows maybe the hoses in the 70's were 'stickier' but in our case the sealant did a wonderful job of making the connection bulletproof while maintaining the original look.

As for Hondabond (also sold outside of Honda dealerships as 'Threebond') it is a wonderful RTV type sealant that I have found to have better properties than most other RTV sealants out there. It seems to spread better but then it tacks up in a nice fashion before it sets. Call it personal preference but it is one of my go to silicone type products in the tool box.

 

Peter sometimes it is best not to question why and just accept that another leak is gone

Glad to hear the sealant worked and good luck on the 308 MOT

 

Very lucky indeed Rob, dont disagree with anything you have said but being a heating engineer, putting any type of sealant where is not supposed to go gives me the shivers, invariably it fails.

I normally find the reason why rubber hoses don't seal properly is because the hose is too big and cannot collapse onto the fitting, even one size larger can cause a problem.

Best

tony

 

As a heating engineer you have forgotten more than I will ever know on the subject. I also totally agree that sealant should be used with care and discretion rather than as a band-aid.

In my instance I did some top of the head calculations when it became clear that the weak link was the inappropriately strong (albeit 'original') clamp that holds the hose in place. I figured that the clamp held the hose on ok but not enough to keep it from moving off the fitting. The fit of the tube to the fitting was quite tight and certainly not off by a size. The sealant, I figured, would give that extra bit of grip between the hose and the fitting and was not being used to make up a fundamental mis-match in sizing. Having monitored the hose over several thousand kilometers I am now fully confident that I have a permanent solution. It has not moved a mm or leaked a drop in three years.

 

Not so sure about that!!

Looking at the composition of Hondabond, it is made up of the following chemicals which is slightly alarming as:-

Xylene (45-55%) is not suitable for contact with Nitrile, EDPM, Neoprene, SBR, Sillicone or Butyl – only with Viton and that has a rating of 3, marginally below the others rated at 4

Chlorosulfonated polyethylene 45% - Cannot find anything on this !!

Butoxyethanol - 1% Not suitable as 1 above.

In our trade we need to look at how all fluids / chemicals within piping systems interact with material they come into contact with, the gaskets, seals and valve diaphragms so forgive me for being a little concerned on this topic.

However your experience and product testing seems to have worked in your case which is great, in theory it shouldn't, but we know all about theory at times!!!

Best

Tony

 

Isn't the xylene only a carrier that evaporates off for the most part?