1967 Fiat 850 Coupe

Dexcool AntiFreeze
"I used to see better results when using original GM brand. Now with so many Dexcool clones, it's a risk!"

Don't know what to say about this, but it is the results of using a generic brand of Dexcool at  50/50 mix ratio. After only 2-3 years and under 3,000 miles the cooling system is full of deposits and or rust. The orange stuff may not be rust, but rather orange deposits from Dexcool.

The Left alloy housing in the picture below used Dexcool.
I've used Dexcool before, but I guess not all brands or batches are the same. I'm not sure about saying the deposits are from Dexcool, but I removed the O'Reilly brand Dexcool anti freeze and installed PEAK brand Dexcool and hope for better results.
The housing to the right is what I'm working on from one of my previous posts regarding temperature senders.
Maybe plain water or standard Glycol based green antifreeze will do less damage. 
I can see corrosion maybe reduced or eliminated with Dexcool, but excessive orange deposits are not a trade for the better either.

 

What I've been told is DexCool helps prevent galvanic corrosion, so I started using it with some success on my Fiat 600. Now, after some research, I found that DexCool qualities are degraded when subjected to air. I've removed my coolant several times exposing it to oxygen which turns on chemicals which form HARD deposits on all surfaces: rubber, alloy and steel. Old cars typically don't have sealed cooling systems either, so they are constantly exposing Dexcool to oxygen.
What I expressed in my previous post is the Hard Deposits are a problem with Dexcool and not the Fiat/Alfa Alloy corrosion we are more familiar with. The thermostat is also covered with a film which doesn't come off easy. It's not rust either, since the Thermostat is brass and the stuff won't rinse off!

I think DexCool can do more damage by the deposits it's capable of forming rather than the corrosion it prevents. Probably depends on how much it's exposed to air.

There's a lot more to the antifreeze debate, plus others can probably correct me or have other experiences. I'm just very disappointed  with the mess Dexcool created inside a cooling system I put so much effort into fabricating. It was new and clean a couple years ago and NOW it's full of hard deposits. I'm assuming I ruined the  Dexcool when draining it in a large drain pan where it was exposed to air for many hours. It could also be the "generic" brand of Dexcool I used which my fail more easily than a non generic brand.   

Those zinc anodes are a good way to help us keep our aluminum where it belongs, that's for sure. That will probably be what I'll do next along with standard antifreeze. I may try the Redline with distilled water since I have some already. I heard zinc anodes are also available from hot water heaters, so I may have a look at some plumbing or hardware stores along with Summit Racing.
 

Yes, It's really a shame since the inside the the engine and cooling system looked new. Now it looks like it has a hard orange cement coating on it.  
I think most people use Dexcool for it's longevity, which is GREAT in reducing maintenance. I ONLY use it for it's capability at reducing Galvanic Corrosion.  
 
Dexcool is orange or should I say was originally orange. I just replaced it with a Peak brand Dexcool "compatible" or "long-lasting" coolant which I think was a bit yellow. I didn't look at it much as I just wanted to get it in the system with minimal exposure to the air. I hope someday to replace it with a NON Dexcool product.
When it 1st became available from GM about 20 years ago, I immediately thought it would be good for use in Fiats since it's was developed for  reducing corrosion problems on Corvettes with the new alloy blocks. I still think it reduces heavy damage from corrosion, but using it can be tricky and formulations of it might be different than what GM originally specified. Now we even have a new derivatives of Dexcool which are marketed as compatible to Dexcool or regular Glycol types.
Still nice to have more options such as WaterLess coolent, which was unheard of 25 years ago.  

The red car's history is unknown to me, but it may have come from Sacramento as the current owner will go to any extent to get these early series 1 coupes. 


Glad you like the car and find the posts informative      Click on this link to  Xweb fourms for more on this car and similar cars


At a recent car show an on-looker liked the car too! She said it matched her nail polish. 

  
Transmission Mount Fix

Transmission Mounts usually fail from cracks such as these that usually start in the corner, but sometimes start elsewhere such as the bolt hole. 



The only fix I've known about is to weld up and reinforce all the seams in the mount to prevent failures. Well, here is how that works in the photo below. You can see the extra weld beads if you look closely, but the steel still cracked next to the weld.


This is what I did to see how it works out. I used some angle iron which is thin wall but a thick corner section. The thinner the better when it comes to using the original mounting studs which are rather short. Next TA I rebuild will include longer mounting studs.







Why do they crack?  I wish I was an structural/metallurgy engineer/expert, but my guess is a combination of things which might be these two little pads (pic below) where the mount is bolted to have very little surface area which may allow too much flex. Another could be that the mount is made of thin metal not heavy duty enough for the 850 heavy cast iron TA case.  


Here it is in it's final mounting position. For now I just did the left side since that is the one I normally have trouble with.

Just came across this one. Such a pretty little car. The blue works very well too I think. Your in debt description of it's problems and your work on it sure is a good read. Very nice one, gotta love the small Fiats.

No alignment issues since it's not a precision fit affixing the trans-axle to the chassis mounting points. The transmission mounting nuts which are loose situated inside a welded cover (in the chassis) are free to move and align with the transmission mount bolts.

There is a limit to how thick the reinforcement metal is since the mounting studs in the transmission are short. Next time I build a transmission I'll install longer studs and that will allow more freedom for different thicknesses. In my case, one side of the angle iron was thinner than the other.  

Your correct on this being the most common failure point on 850's.  Other than that, maybe throttle cables? Idler arm bushings? Maybe these things are common "wear" items, but for failure, I would say it's the transmission mount. 

 I've had some cooling problems that never really got out of hand. By that, I mean the factory water temp gauge would start climbing but never go all the way to red.
 I could tell the cooling fan was not turning on, so my assumption was the Fiat gauge and/or fan sensor in the VW Scirocco radiator are not operating together properly.
They are a marriage of VW (rad temp sensor) and Fiat parts (Cylinder head sensor) so I didn't trust them. I just decided to buy another more robust water pump since mine was used (LOTs of Hours!) and a smaller version.

Now I didn't trust that a Bosch pump would be good since it's not specifically designed as as a replacement for a mechanical pump. I did some research and found Hillman Imp racers have been using them for years.
There are specific electric pumps made for automotive applications, but I found the pricing way too high and thats the reason for the Bosch pump.
I started to experiment with junk yard pumps which worked out rather well. After some initial problems, I ended up installing a second pump in front of the car behind the radiator thinking 2 pumps would be better than one. I found it didn't make any difference. So now the second pump acts as a backup, just in case the rear pump fails. I installed a switch under the dash that turns on the front pump, which I normally leave off.

Here is an example of Bosch pump install on an IMP.


 
After doing some testing with the fan electrical, I found the fan relay terminal had loose connections inside the plastic plug on the relay. I reset the spaded terminal lock tabs in the terminal and plugged it back in.
We'll see what kind of cooling improvements we get with the new changes.









The water pump purchased from ebay looks like it came from a company in the links below. The pump came as a kit with the terminal pigtail and mounting bracket. The bracket with the anti-vibration pads seems to be a good compliment for installation. The wires could be a larger gauge to handle the higher amperage draw of an electric motor vs a fuel injector.

Here are a few links related to electric water pump options:

AVT Electric Water Pump Clamp Mounting Kit Bracket
4.25" Pump Mounting Kit
Magnetic Drive - impeller contained in totally enclosed chamber
Bosch Pump Specs -317 GPH (PDF)

Mercedes and Porsche use the small pump I originally used to prevent hot spots from soaking into parts aluminum engines, by running pumps for several minutes after shutdown. It is not just for the cabin heater like I originally thought.
Ideally I'd like to have timer system to keep the pump running for a few minutes after turning off the ignition.

Bosch part number 0 392 022 002 is used in many of the supercharged Mustang Cobras and supercharged Mercedes. It's used as a Water to Air Intercooler Pump which should have at least a 16 gauge wire. Most connectors you will find being sold for this pump (and what I have) are fuel injector connectors with 18 or 20 gauge wire which may result in poor pump performance, voltage drop, or dangerously hot wires. I'm partially using 16 ga, where I  just soldered it from the end of the pigtail.


 

Fitting of Oil Pressure Gage