Couldn't find a similar issue so let's have your experience or opinion.

1987 S4

Replacing my heater hoses to the heater core. Once I had the old one's off I see that the heater corre connections have some pitting and while it might not be an issue I sure don't want to have a leak there after everything is back together.

Is there anything I could use to help "seal" this connection? Something like make a gasket or something? Wouldn't take much to fill in the pitting and ensure a leakproof seal.

 

Try it with nothing except a hose clamp and see if it leaks. Most times I've seen cars with gasket adhesive or RTV added, it's caused many more problems than it's solved. Unless there is a continuous path through which the coolant can flow to get out, a little bit of pitting won't cause you any issues.

BUT.....

The evidence suggests that there may be a bigger issue to bother you, and that's worrying about the cause of that pitting and what other damage might have been done elsewhere. Make darn sure that there are no flush chemicals used on your cooling system, and that you are using a suitable coolant in the car. There are several differing opinions on what the most appropriate coolant is. We do know that mixing coolants by not flushing the old out completely is a no-no. The general philosophy extends to using a phosphate-free coolant, and for some a silicate-free product seems important. The silicates give you a certain amount of water pump seal lubrication --IF-- you drive the car regularly enough to keep the seal face wetted with the coolant. If the car spends extended time parked between drive, the no-silicate issue becomes more critical. Whatever, your corropsion pitting at the heater core nipples could be from poor flushing in the past, of from undermaintaining the cooling system. Flush with the heater on high temp so the core and its dedicated plumbing and hoses are cleared of old coolant before you add new. Flush with the block drains pulled. Use distilled water for your coolant mix, topping with the distilled water after you've put in your desired amount of coolant. I add a bottle or two of Redline Water Wetter to add some system protection as well as improve heat transfer. A quick search will bring back long-winded results on cooling system issues, something to use to fight that insomnia problem you've been experiencing.

 

I can add two things to Dr. Bobs excellent post.
Try Avaition permatex "form-a-gasket" on the hose connections. It stays flexible and seals.
Use G05 antifreeze. Don't use "universal" antifreeze. NAPA stocks Zerex G05.

 

+1 on the Zerex G05. That's all I'll use and I will change it every 2 years. This is what happens to the heads if you use the green stuff and leave it in too long...

 

I'll pile on to the Zerex G-05 Gold recommendation. The big local places like Pep Boys, Advanced, and Autozone no longer have it, probably because the Prestone guys have bought up the shelf space. NAPA and the local CarQuest parts warehouses still carry it.

AO, a little work with the Dremel with the wire wheel and that head will be good as new!

 

For those of us that live in SoCal and are not subject to freezing, what are the thoughts on running straight distilled water with water wetter/Mo-kool/etc for lubrication of the water pump and some preservative effect? With the caveat that it's drained and filled at least annually, if not more often.

 

I had a similiar situation with my GTS. PO was a southern Calif. owner. The car had minimum antifreeze when I got it 6 years ago. since then it has had almost annual coolant changes. While replacing all of the water hoses in the engine compartment as a matter of routine maintenance I found the steel water pipe on the RH side of the engine compartment. Corrosion was heavy with a small hole completly thru the pipe. Got a used one, then another, then a third (see pics) all were worse than my original. The one clean one is after removing all of the rust only to find pitting worse than my original. I used a small smear of form a gasket on the outside of the pipe just before installing the hose. So far (about three months) so good. If the original one does fail, I'll be making my own out of copper with brazed not soldered joints.

 

Jim,

Most of them look like that, but I have never seen one leak.
I would VERY seriously think about using copper. Aluminum and copper are very different on the galvanic scale. Your radiator could be the first thing to disappear, just before your engine and heater core.

 

I have used solder and lead on tubes like this before with great success, use the same process as you would on copper pipe plumbing. The key is having them very clean the best way I have found is to have a body shop sand blast the corrosion off. When soldering them use a propane torch and have a stick ready to move the solder around if you need to and make sure you clean all the acid flux off before installing them on you car. good luck


paul with to many 928s

 

Sandblast the pitted surface, apply JBWeld, sand smooth. Lasts for a long long longlong time.

 

Already had them welded and decked last winter.

 

Stephen--

I've given that some thought. The Watter Wetter gets you some pump lubrication but no anti-corrosion protection. Distilled water grabs at metal ions, so you'll want some buffering to prevent the water fron scavenging metal from the motor. No issues if you are draining after every race, tough on a street car. My compromise is running a gallon of coolant (I use the Zerex G-05) plus a bottle or two of Water Wetter, rest is distilled water. This gives a 25% concentration, about the minimum you'll want to consider. It gets changed every year or so, no longer than 2 years, even though it's supposedly 'good' for five years between changes. The coolant is less than $15 at local places, Water Wetter is less than $10/bottle, big jugs of distilled water cheap from the market. Cheaper than fighting with corroded coolant piping. Again, the corrosion on the piping is a 'tip of the iceberg' telltale; AO's headshot tells an ugly tale of the rest of the possible problems.

For those playing along at home: Cooling system maintenance is an absolute must even if your car is only a summer or once-in-a-while driver. The buffers and corrosion inhibitors do deplete over time, albeit a little faster when hot than when cold. Still, a correct extended-life coolant is a must. Regular/frequent replacement wil give you a better chance of at least slowing the damage.

 

Thanks Dr. Bob, well written and logical as usual.

I'll be doing my upper radiator hose this weekend and will make sure to get a gallon of G-05 in there at that point.

 

+1 A simple and proper repair.

 

My general feeling is that, by the time the upper hose needs replacing (every 5-10 years) the other hoses need replacing too. The upper hose and heater hoses see the hottest water, they all see the same pressure. Hmmm, that leaves only the lower hose from this selection set.

Another critical hose in the mix include the stubby adapter hose from the head to the heater valve. This one generally sees really hot service. The other heater hoses should be replaced along with the heater control valve while you are having all the hose fun.

Toughest to get to and therefore most likely to be ignored is probably the short hose from the bottom of the reservoir to the transfer pipe on the fender well on the right side of the car. The other connection there is only a little easier, where the heater connects to the reservoir. On my later car there are two 8MM vent hoses from the reservoir, one the to water bridge, and one to the radiator tank vent. There's a coolant pressure switch in one of those vent hoses too.

Of course, while it's all apart and drained, you'll want to replace the thermostat, along with the front and rear seals that go with it, and also put on a new coolant reservoir cap. The plastic drain plug on the radiator gets crispy with time, another WYAIT item.

When you replace the lower radiator hose, don't forget to put a new plastic tie to secure the hose to the fan shroud; Failing to do this risks having the PS drive chew through the lower hose.


And you thought you'd just pop a new hose on the top and call ita a day.


I hate getting stranded by Stoopid Stuff, and coolant hoses definitely qualify. A poor upper hose connection stopped me both times I've found myself on the side of the road with a 928 troubling me. My fault on those, not the car's fault. A bit of care saves a lot of trouble.