mlauritsen

I recently bought a 1973 BBC 'vette, and I was on a longer (1 hour) drive last week, and got stuck in traffic.

I'm a newbie (that was literally my second time out in the car), and so I didn't know what to look for until it was too late.

The engine overheated, and boiling coolant gushing onto the motorway as well as steam from the hood was my hint that it was time to pull over.

How worried should I be? I stopped immediately when things went bad, let it cool down, and I had some water with me to top it up before getting back on the road.

First part of the question relates to the incident - the car drove home fine afterwards, and I have since added 5 liters of distilled water (I will get the cooling system checked, drained and refilled with a known substance - previous owner could not tell me what's in there). What damage could I have done to the engine?

Second part of the question is why did it overheat? What are the obvious things to check? So far, from friends, I've heard "check the timing" and "replace the thermostat to be sure", which is a good start, but what else will cause overheating? It's a 454 CWR, and somebody opined that these are prone to overheating, but does that mean I should accept it?

Thanks for any input!

Ps. I felt very stupid standing on the side of the road with a gushing engine... I'm definitely going to keep an eye on the temp and pull over before the overheating next time. I'm a newbie, and I very much appreciate any info you can give me. I'm here to learn, so feel free to call out anything I should have known or done.

4-vettes

In response to the title of this thread, YES! Bloody Oath you should worry!!!
These cars have many issues with running Hot. all the seals around your radiator? proper radiator, clean, etc. stock fan?? Fan clutch working correctly?? the list goes on and on.
Your a newby. time to make friends with old guys who have been around these old cars for a while.
Join a old car club!

Mr D.

Search cooling system on this forum in both the C2 & C3 sections and grab a cup of coffee. You can start at the below link.

Corvette Cooling

augiedoggy

A worn out fan clutch can also cause this problem. I had an issue with my small block where the temps would climb to about 205 while sitting in traffic and that was with a 180 stat and new 3 row rad. ended up going to electric fans from the stock setup which have the ability to cool at full power even when sitting at idle... car idles at 172 all day now.
hopefully your issue is just a result of needing your coolant system flushed.

derekderek

did you run the engine completely out of coolant? no. then it didn't get that hot. i don't think you are asking if overheating issue is worrisome. i think you are asking did you hurt that engine. no. big blocks are tough. there is a thing in boating about how an engine can handle a certain amount of power based on how much mass it has. not bore by stroke. but how much iron is there to play back-up cooling system if coolant gets low. light thin blocks can start to self destruct the instant there is an air pocket in them.

interpon

how about some pics?

HeadsU.P.

Here is a general rule about overheating:

Overheating at speed, is a Coolant Circulation issue.
What this means is, plenty of air at 70 MPH, but W.P, Rad, Lower Hose, etc, can't keep up. But why?

Overheating at idle is a Air Circulation Issue.
This means the W.P. fan belts, lower hose etc are likely ok. Just can't get enough cooling air through because the vehicle is sitting still. But why?

Greg

What was the ambient temp (approx) when your car overheated?

Eric P

Does this look like straight water or does this have a good antifreeze mixture ? straight water boils 212 degrees which isn't really hot , if it looks like you have a good antifreeze mix then disregard this message , if it's pure water then start here with a top off of full strength antifreeze

1860army

These guys have you covered on the Overheating issue, at least a good start. My comment is you have a "Brand new" 40+ year old car, I would not be taking it on a one hour drive until I did a bunch of maintenance and checking, and shorter shake down cruses... These things can hide a lot of issues and it's Better to have them happen close to home than an hour away.

Congrats on the car

60

F4Gary

OP, did you ever look at the temperature gauge?

resdoggie

Ask the previous owner how old is the rad? A shiny new aluminium rad might be in your near future.

67:72

Your problem is probably a combination solution.

What does your radiator cap look like? (picture)
If it's not building pressure adequately, the coolant/water mix will boil below what the system is designed for. In other words, if the cap is not pressurizing the system, a 50/50 coolant/water mix will boil at about 225F; when pressurized to 15psi it will not boil until almost 270F.

HeadsU.P.

You were stuck in traffic. No air flow or little air flow through the radiator.
So, why didn't the Rad get enough air?
Foam seals installed around the Rad?
Clutch Fan ok?
Fan belt condition?
Fan Shroud in place?

If you have compressed air, give the outside of the Rad a thorough cleaning forcing air through backwards.
Or use a garden hose, same way. You may have years & years of bugs, leaves, road grime in the Rad fins.

mlauritsen

Sorry, I phrased that badly. Naturally, I _am_ worried, otherwise no thread.

I'll get the cylinder pressure tested and then check, clean and refill the cooling system, just wondering what else I should look out for. Thanks for the quick response.

I am signing up to clubs as we speak, just takes a while to meet the right people... This is one of those times where corona really really gets in the way...

mlauritsen

I have learnt to not trust the previous owner. Cooling system seems to be full of water, not sure he bothered with distilled water, probably just from the tap.

When I picked up the car, he gave me a quick tour, then handed me a bottle of water "just in case" and sent me off, knowing full well that it was prone to overheating, and the alternator (not charging, since replaced) and battery (from 2013, couldn't hold a charge, since replaced) were not OK. The vette died on me in the middle lane of the motorway, during heavy traffic.

So I'm going to approach these issues as if the vette fell from the sky and ignore anything he told me.

Don't mean to moan (I'm sure he did what he could, and the vette+BBC are sweet apart from the problems) just for context and to address any "ask the previous owner" suggestions, which otherwise would have been sound advice.

mlauritsen

I did, but it overheated around 210F, and having been raised on celcius, I wasn't prepared.

Overheating at ~210F means it's pretty much all water in there, right?

I will get the system checked, cleaned and refilled with proper coolant - I might spring for waterless, I'll do anything to never overheat again.

Mr D.

Water boils at 212*, adding a 15-psi radiator cap will raise the boiling point by 45° F and with the proper coolant mix (50/50) and radiator cap the boiling temp is raised from 212° F to 268° F.

You have other issues if the radiator is boiling (puking) the water out at 210F indicated on the temp gauge. 1) the temp gauge is not reading correctly, 2) you have a bad radiator cap or 3) water flow or air flow issue.

My 65 427 car ran on the hot side of life and always indicated 210ish on a hot day and the gauge was reading about 10* high so I guess I was steady state at about 200F. While I always felt it was running hot it never boiled over.

resdoggie

I have a feeling the rad is clogged with deposits that accumulate in the bottom of the rad and scaling on the tubes. So no matter how much air flows through the rad, the rad has probably lost a third or more of its cooling capacity. Take a look at the few tube ends you can see with the cap off for any scaling.

Hopper12

Hey OP, welcome! And I hope you get lots of enjoyment from your 'new' C3.

First, I'm with the other members on the very low likelihood you did anything bad to hurt your engine. And the PO sounds like a schmuck. Now on to the cooling system.

I'm a firm believer that a properly set up and maintained stock cooling system will work no problem - with a little help. And I highly recommend NOT throwing bandaids at this problem. You'll just find the next weak point in the cooling system and you'll constantly be concerned when you go for a drive. Our C3 is a '68 427/435 and it now runs 180 degrees in traffic on 100+ degree days. Here is what I did.
* Replaced the radiator with a DeWitts direct fit. I kept the old one in case anyone down the line wants it. DeWitts isn't cheap, but you'll only wince once.
* Replaced the heater core because it had a slightly loose heater hose pipe, but also because it was over 50 years old and I wanted the cooling system to be completely fresh (and I found a couple of small leaks when I pulled the cover off). You may not have to, but I did.
* Replaced the fan clutch with a rebuilt one made for our engine.
* Ensured that I had the right fan for our car - it was the original. Stay away from flex fans and the like. If the PO replaced the fan with something else, you can get a stock fan in the 'parts for sale' section of this forum.
* Replaced the water pump with a rebuilt unit. And I pulled the back off to ensure it was good, for just the cost of a gasket.
* Make sure you have the correct radiator shroud. If you don't, you can get one in the parts for sale section.
* Ensure you have the radiator and shroud seals in place. All of them. Don't skimp here. The fan can only pull the air thru the radiator if there isn't an easier way around it - kind of like water.
* Replace the stat with a 180 degree one.
* Replaced all the heater and radiator hoses and clamps.
* Put in a 50/50 mix of the good old green Prestone.

If you do the above, and your motor is clean inside and tuned correctly, you'll not have to worry about staying cool. Then you can spend time learning about all the other fun stuff with your C3!!

Show us some pics, keep us informed, and best of luck! Paul