Petes75Vette

I've come up with a new issue that I believe I need help with.

Last summer my fans weren't turning on (dual fan setup). I tracked down the issue and replaced the thermostat + electric fan control switch and wiring. All worked wonderfully, and the fan turned on as it should.

The car was having some rear wheel issues, so I didn't get to check my work too much with the car moving, but refilled the fluids we had lost through the overheats we had while figuring things out, and was happy that the problem was solved. Trailered the car to storage and thought I was good to go.

This year I had a shop finally fix my rear wheel issue, and I drove the car home, on the highway, 13 miles. It was 50 degrees out and sunny...so a little cool. I noticed that the temp was slowly increasing, and figured this was weird due to highway speeds/wind and cool air temp.

When I pull up home, the temp guage was reading all the way to the right, but just barely below the "red"/danger zone. I pop the hood, and brownish fluid is bubbling out of the catch can (if that's what you call it).

Now, I'm not sure if something is wrong that I don't know about causing the system to have "brown" in it. I had used just water when refilling the system. Additionally, I'm not sure if this overheating was caused by a leak somewhere, or if we had not correctly refilled the system the previous fall. No leaks are apparent, and the fans were on and working when I popped the hood.

Any idea what the cause is. Being quite new to working on my own cars, I'm still unsure of how the whole radiator and fluid setup should work properly, be filled properly, etc. Thought I had done everything correctly.

Any help is much appreciated.

This is a crate 350 motor. About 2 miles on it. The fan setup seems relatively new (replaced just before I bought the car), the electronics/temp sensor all new, radiator looks very new as well.

It's a 1975 automatic Vette.

doctorgene

Just Water is a NO, NO., It will rust the inside of the block fast. Clean it out with a good radiator flush, refill system with 50/50 Anti-freeze. That should take care of the Rust problem. Overheat; I think I would get more of the radiator gaps plugged up. All that room around the outside of the Rad. need to be blocked up to force the Air through the Rad. Also I have not seen the fans set up like yours. Most set-ups have a shroud over the Rad. fins that show on yours. I don't believe this set up will work correctly. Hope I'm wrong. Have a great day. Gene P. S. Look at a Dewitt set-up. Do you have 190 degree Thermostat???

Roco71

100% water will cause corrosion inside your block I have seen it eat the impellers off of a water pump. I am not a cooling expert but the lack of a shroud is not helping your cooling issue. Some other I am sure will comment to help you with that part.



The Dr can type faster then me (LOL)

CaseyJones

Check the thermostat and radiator hoses. Always check the basics first before panic sets in. Probably something really obvious and simple. And yes, you do need to flush the system and refill with the proper fluid mix.

Just asking here, but are the fans pulling air or pushing air? Just because they run doesn't mean they are doing the right thing...

chevymans 77

looking at the pics you need to make sure to install all the seals around the radiator and core support, looks as if you have none. They are needed to force all air to flow through the radiator

Neal

69 Chevy

You won't get much airflow by driving in reverse.

Petes75Vette

2K is what I meant. 2,000 miles or so on the motor, as I was told when purchased it.

Thanks for the input folks. Flushed the radiator today, some rusty water at first (to be expected considering I ran only water and she sat for the winter in storage)...but it wasn't too bad. Flushed out, and now filling with 50/50 yellow Prestone. Also going to add water weter for good measure. I'll keep this thread updated if I have any overheating issues coming up.

As far as I can tell, all should be good. We'll see. I did read a post today on hear where a gentleman had a similar issue. Never overheated around the city, but on the highway it always got super hot. As soon as he got off the highway, the temp dropped to normal. The consensus on the thread was that a change to a Dewitts radiator fixed the problem.

Hopefully that's not the case with this!!

Petes75Vette

Checked, and the fans are definitely pushing air AT the engine.