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Discussion Starter #1
Hi Guys,

Another S4 heater problem. When I replaced the heater hose, I noticed that the nipple or barb on the intake manifold was pretty rusted. I removed it today and the steel is very thin and near the end, there's a big chunk missing. I tried to find a replacement part and no luck. First, the local stores - I love the look on the clerk's face when I say the word Alfa Romeo. Most have no clue what and Alfa is! No luck at the auto parts store and I even checked the hardware stores and no luck. I tried on line and all I can find is brass - brass will attack the aluminum - galvanic action. We don't want that! So steel it is, but I need to find one that will work.

The part I need is the M14 nipple/barb that mounts to the intake manifold. The heater hose connects to this piece and the hose enters the firewall on the drivers side (left).

Any ideas?
 

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I tried on line and all I can find is brass - brass will attack the aluminum - galvanic action. We don't want that! So steel it is, but I need to find one that will work.
dunno
the throttle body is aluminium and the heater hose nipples there are all brass.
the motronic sensor and the temp gauge sensor are all brass, and they screw into the inlet manifold....probably other stuff too
motronic tempertature sensor.jpg

so I'm not getting why it has to be metal (that rusted away on yours...!)

Any ideas?
I have a brass one that is probably identical to the metal one you just took off (M14 x 1.5 thread, for 14mm ID heater hose)........but it's good old non rusting brass:)
it is from an '90/'91 S4 throttle body (euro), where that heater hose fits onto the throttle body, not the inlet manifold, as on your post `92 spider.

heater connection1 jpg.jpg
 

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I tried on line and all I can find is brass - brass will attack the aluminum - galvanic action. We don't want that! So steel it is, but I need to find one that will work.
With the proper coolant mixture. That won't happen.
 

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Discussion Starter #7
Hi Jim,

Thanks for the link. I checked for the one I need and they don't have it. I did some more checking on the internet and I think I found it.
 

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Discussion Starter #8
dunno
the throttle body is aluminium and the heater hose nipples there are all brass.
the motronic sensor and the temp gauge sensor are all brass, and they screw into the inlet manifold....probably other stuff too
View attachment 1621594

so I'm not getting why it has to be metal (that rusted away on yours...!)


I have a brass one that is probably identical to the metal one you just took off (M14 x 1.5 thread, for 14mm ID heater hose)........but it's good old non rusting brass:)
it is from an '90/'91 S4 throttle body (euro), where that heater hose fits onto the throttle body, not the inlet manifold, as on your post `92 spider.

View attachment 1621597
That's the one!

The part on my car rusted, because the previous owner didn't maintain the cooling system. My gut feeling is that he ran it with either very little or no coolant. The steel rusted through and the inside of the fitting is very thin.

I just found the steel one on a website. I prefer steel over brass for fittings like this - just in case I screw up and let the coolant ratio get too low, the steel gets eaten, not the aluminum. Though I just thought about that logic and it isn't very good, since there are other sensors in the cooling system that are made from brass - the aluminum acts as the anode with brass and the anode is the part that gets eaten.

Thank you.
 

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Discussion Starter #9
With the proper coolant mixture. That won't happen.
Hi Jim,

You are 100% correct! I read that the coolant mixture must be at least 15% for it to protect from galvanic action. My car was not maintained and the nipple was severely eaten away. My guess is the aluminum near the brass sensors may be damaged too. I'm worried about it, but I don't want to take things apart right now. The head gasket is also shot - will need to be replaced too.

It's raining today, but when the weather is better, I'll take a picture of the old part. You'll be shocked to see the damage!

Thank you.
 

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I'll take a picture of the old part. You'll be shocked to see the damage!

Thank you.
After 10 years of working on Alfas then moving to mahogany boats for the last 25 years. You would be surprised at what I've seen.

The closed cooling systems on marine engines are made up of copper, brass, steel, galvanized steel, aluminum and cast iron. All that together on one system. As long as you get the mixture around 50/50 you will be fine.
 

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Discussion Starter #11
Here's the part I bought. It's suppose to be M14x1.50 x 14mm, but this part is 15mm at the nipple. I have a 15mm fitting I pushed the hose on, just to test it. It did okay with some dish soap, so it should be fine. The other big plus is that it's made out of aluminum, not steel and has an anodized finish. The washer is steel and it's teflon coated.

It's some sort of performance part. Coming from England in 4 days! I have no idea how they can get parts here faster than if they're ordered in the states. Makes no sense to me, but in the past I've ordered from Classic Alfa and the parts come so fast.

Thanks to everyone for their help - as always, you guys are awesome and the sharing here is inspirational!

I'd like to add some help to other S4 owners, so if anyone is looking for one of these, here's the link where I bought mine. M14 X 1.5 to 15mm (19/32") Barb Fitting Straight Adapter With Washer 14mm | eBay $10.44 including shipping to CA!

1621739
 

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Discussion Starter #12
After 10 years of working on Alfas then moving to mahogany boats for the last 25 years. You would be surprised at what I've seen.

The closed cooling systems on marine engines are made up of copper, brass, steel, galvanized steel, aluminum and cast iron. All that together on one system. As long as you get the mixture around 50/50 you will be fine.
I'm going to look for a table describing anode and cathode metals. The more noble metals act as a cathode, while the less noble ones act as a sacrificial metal.

My education (first degree) was in engineering, so I understand things about electrons and the galvanic process - the science part of it.
 

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That was easy. Here's one of the better charts I looked at. It shows which metals will remain and which ones will deteriorate when in water.

For those who have a tank water heater, you'll find a bolt on the top, which holds the anode rod - I've seen one manufacturer who puts the anode rod below the water nipple (I forgot if it's the in or out line). Since the water tank is made of steel, the galvanic action will cause the water tank to be eaten, but if you put a metal rod into the tank, the metal rod will become sacrificial and will be eaten up instead of the tank. Most water heater failures arise from holes in the tank from galvanic action. Anode rods are mostly made of magnesium, but I've seen zinc rods too. So the rod will be the anode and the steel the cathode. The anode loses ions (pieces of it dissolve into solution), while the cathode received electrons.

For those who are thinking about using the electrons, you're on to the concept of a cell or battery (multiple cells). AA,AAA,C and D cells are dissimilar metals that form a galvanic action to create electricity (source of electrons) - think of a canister made of Zinc = - charge. The top of the cell connects to the carbon rod which is bathed in a paste = + terminal.

This is way too far off the subject. Use the chart below to control the destruction of metals (corrosion) when in water.

1621740
 

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The new anodized water heater barb just came in. Wow, nice packaging. They sent it with a steel washer with a rubber seal - nice. Super light weight, nice finish!
Glad you got the part and the issue sorted.

Thanks for posting the part and source. That is definitely not a part we see often come up on the BB for discussion.

Vin
 
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