Question: Fire Breathing Dragon...

[GreenFields]

...well maybe not fire but definitely breathing steam

I got stuck in some pretty heavy traffic a few weekends back - a jam to be precise (in the region of 45-minutes spent crawling along at 5-10mph).

By the time I got home, the radiator was blowing water out of the expansion pipe (as above). The next time I drove the car it did a similar thing, albeit in a much reduced fashion.

Since then, it has been fine and the temp gauge is reading in the middle (not even touching the orange).

I checked the rad today, and it wasn't full to the top (probably half full).

I've topped it up but expect it to do it's best dragon impression the first time I drive it.

So, I've got a few questions for this esteemed online panel of experts :-

1) Is this par for the course for the C2 (and in particular, a BB)?

2) When I've driven the car, it never reads hot, even with the rad half full; therefore, should I just leave the rad as it is and not worry about it being full?

3) has anyone done an expansion tank mod for the rad? I'm wondering whether it would be a good idea to have a tank which can take the water as it expands and the rad can suck it back once it cools down.

Thanks in advance guys

 

[GreenFields]

PS - just so you don't think I'm asking questions without reading other relevant posts, I have and while this thread: -

http://www.corvetteactioncenter.com/forums/showthread.php?t=107187

...did help, I question how much is relevant as my car isn't running hot (the temp gauge is new and working fine (or at least it seems to be).

 

[JohnZ]

1) Is this par for the course for the C2 (and in particular, a BB)?

2) When I've driven the car, it never reads hot, even with the rad half full; therefore, should I just leave the rad as it is and not worry about it being full?

3) has anyone done an expansion tank mod for the rad? I'm wondering whether it would be a good idea to have a tank which can take the water as it expands and the rad can suck it back once it cools down.

Thanks in advance guys

Some basic questions first:

1. Do you know the history of the radiator? Is it the original or a replacement? Correct configuration?

2. Have you checked the temp gauge reading vs. an I.R. gun shot of the radiator hose just above the thermostat housing so you know what it's telling you?

3. Are the fan, clutch, and shroud all in place and correctly installed?

4. What does the temp gauge show when it's steaming/puking from the overflow hose?

5. Which engine/transmission combination?


If the cooling system components are functioning normally, it may heat up above normal under the conditions you described, but not to the point where it steams/pukes.

A couple of things can cause "puking". If the radiator cap won't hold its rated pressure, the coolant can boil at a lower temperature, especially during hot-soak after shutdown. If the radiator coolant level is too high ("topped off" when cold instead of set at the "full-cold" line on the side tank), there's no space to accommodate coolant expansion when hot, and it "pukes" through the overflow. If it's set at the "full-cold" line when cold, that provides adequate space for coolant expansion.

 

[GreenFields]

Hi John,

Some of the questions I can answer right away, others I will have to check when I get back home and can take a better look at the car: -

1. Do you know the history of the radiator? Is it the original or a replacement? Correct configuration?

I believe the rad and much of the cooling system is new (less than 2-years old); however, will check the previous owners bills when I return home. I believe it is the correct configuration as it was done by a reputable specialist.

2. Have you checked the temp gauge reading vs. an I.R. gun shot of the radiator hose just above the thermostat housing so you know what it's telling you?

The gauge was reading faulty, so was replaced by the previous owner. I have been told it is reading true; however, I have not done a manual check using an IR gun. I will add this to my To-Do list

3. Are the fan, clutch, and shroud all in place and correctly installed?

Visually all looks fine and the fan is working. I will take a photo and post it - perhaps someone can comment as to whether it is a suitable set-up.

4. What does the temp gauge show when it's steaming/puking from the overflow hose?

It sits happily East (right) of the middle (210 iirc) - never venturing into the warning area of orange or red

5. Which engine/transmission combination?

427 4-speed

In terms of the "topped off" level, I'm struggling to find a level indicator on the rad. A visual check, when removing the top cap (when cold), seems to show about 2/3 full.

And this is the basis for my question - perhaps this is fine as the fluid needs room to expand? However, it seems strange that there is no external expansion tank and I wondered if it was worth fitting a clear bottle so that I could monitor the fluid loss/expansion?

As you can tell, I'm used to modern cars and while I love the C2, it is uncharted territory me... hence the, probably, ignorant sounding questions.

Apologies in advance

 

[JohnZ]

5. Which engine/transmission combination?

427 4-speed

In terms of the "topped off" level, I'm struggling to find a level indicator on the rad. A visual check, when removing the top cap (when cold), seems to show about 2/3 full.

And this is the basis for my question - perhaps this is fine as the fluid needs room to expand? However, it seems strange that there is no external expansion tank and I wondered if it was worth fitting a clear bottle so that I could monitor the fluid loss/expansion?

Which 427 - 390hp or 425hp?

Original Harrison big-block radiators had "full cold" embossed on the engine side of the RH side tank, about 3" down from the filler neck; Harrison or not, that's where your (cold) coolant level should be. That was standard design practice in the 60's, long before the sealed cooling systems with pressurized "hot-bottles" we see today, and it worked fine if all the components were operating correctly.

 

[GreenFields]

Original Harrison big-block radiators had "full cold" embossed on the engine side of the RH side tank, about 3" down from the filler neck; Harrison or not, that's where your (cold) coolant level should be. That was standard design practice in the 60's, long before the sealed cooling systems with pressurized "hot-bottles" we see today, and it worked fine if all the components were operating correctly.

John, you're a gentleman! That is exactly what I needed to hear!

As soon as it stops raining, I'll take her out for a spin and check to see if I can see a level on the side.