Coolant / Antifreeze

['66 Sting Ray]

Morning, All....
Yesterday the C2 overheated - badly - while sitting in traffic in Bookham. Coolant spraying everywhere, though out of the rad cap, which looks sound. A fellow CCCUK member came to my rescue. I filled the radiator up with (three litres) of water. I'm going to get one of those anti-freeze testers, but curious which antifreeze and mix I should put in? Not looking to do a full flush unless necessary, although there was an extraordinary amount of pressure on the system when it went. Never had the issue before, even in warmer temps, and the needle on the temp gauge was never more than three quarters. Heat and defrost pumping hot. Thanks!

 

[Oneball]

If it’s not done it before I’d be looking for why it’s done it????

I use normal blue glycol antifreeze. I buy the ready mixed stuff in a 5 gallon drum. For example

20L Mannol Coolant Antifreeze AG11 Blue Ready To Use Longlife High-Specification | eBay

“Contract”. “Contract Price”. Third Party Rights. ZONE D - Scottish Offshore Islands - HS, IV41-49, IV51 -IV56, KA27 & KA28, KW15-KW17, PA20, PA41-PA49, PA60-PA78, PH42-PH44, ZE, Channel Islands and Isle of Man (IM).

www.ebay.co.uk

 

['66 Sting Ray]

Thank you very much. And yes...I am hoping it was a one-off. It wasn't a searing hot day yesterday, but it's never sat in a traffic jam for a full half hour. And I am more than a little curious why the gauge didn't suggest it was running hot.

 

[Oneball]

I’d check the radiator is hot top to bottom and the thermostat is working properly.

 

[Stingray]

I know nothing about those engines. Where is the water temp sensor located?

Anyway, in general terms your symptoms might indicate a dodgy water pump. Water boiling in the block while cool in the rest of the system.

Another possibility might be thermostat stuck shut - but they more usually fail in the open position (which has obvious attractions).

Possibly a faulty temperature sender/gauge means the needle's moving but not showing correct reading.

 

[Roscobbc]

Remember that if the temperature sensor is located in the head or inlet manifold and you are low on coolant......the sensor won't always be immersed in coolant......and therefore may not indicate 'real' coolant temperatue. The trick in that case is to 'read' an abnormal rise in indicated temperature early enough and react before a major problems occurs.

 

[Forrest Gump]

Check the viscous fan is working properly too.

 

['66 Sting Ray]

Thank you all! And yes...sticky / corroded thermostat was the culprit, so well done, Stingray, and yes, Stingray and Roscobbc the temperature sensor was located ahead of the overheated part of the system, which is why the gauge wasn't buried in Satan's butt. Spliced out the middle of the thermostat, which will avoid all overheating problems in the future, though I'm now worried it won't sufficiently heat up the system of a cold winter morning, not that it will be taken out much over winter. Thanks again.

 

[62 C1]

I use Evans Power Cool 180 which i would recommend. It is a bit expensive to start with but is good for 10 years. The key benefit is that is is not water and therefore doesn't boil at 100 deg. As the name implies it has a much higher boiling point. Not that you would really want to do this but I have seen the radiator cap removed with no problems when a car was running at well over a 100 deg. The other advantages are that it doesn't pressurise your as much hoses because the liquid isn't boiling and because it is not water your metal parts like the thermostat don't corrode. 5 litres are about £65 on eBay or Amazon but it is well worth it. Make sure you completely flush your cooling system when you switch over.

 

[Roscobbc]

Interesting stuff (Evans Coolant) my engine takes about 12 to 15 litres to fill up so quite expensive - I think it's great for a 100% 'good' cooling system that have never (or ever likely to have) overheated or a hose burst and had major coolant loss........could get very expensive.....

 

[teamzr1]

For those GM engines that were designed for GM'S Dex-Cool anti-freeze and I notice on Evans website states :
Some vehicle manufacturers may not yet recommend or endorse the use of Evans waterless coolant

NO matter what a vendor says, I would suggest asking GM before replacing it with Dex-Cool

It also states :
Typically this application will run the same temperature or slightly hotter than 50/50 antifreeze.
To decrease the operating temperature there must be improvements to the system.

I thought this was odd Evans saying this :

62 Corvette - should I remove the thermostat?​

Hi, I recently converted my 62 Corvette to Evans high performance, the car seems to run about 20 degrees hotter which I thought might happen, but I was wondering if I should change my thermostat (180degree) or run a restrictor or eliminate the thermostat entirely?

Don:
First thing to try is eliminate the thermostat completely. Let us know what the operating temperature is after that.

The problem with that is, with no Tstat the fluid is flowing much faster through the radiator and has no time to cool down
To me the correct change is swap with a higher volume flow radiator
I shimmed the stock Tstat from the 194 F deg to 180 deg

Also, I did was then used a heat exchanger that the coolant then flows across a coil and pulls heat out of the engine oil,
vented hood to pull out heat and remotely mounted the oil filter, with a truck filter that is twice as large as stock filer was
so with the added oil lines oil volume increased by 3 quarts so oil temp states about 190 F deg

If wanting to shim GM stat if like this design, I did a lot of testing and way to shim

Shimming Tstat

My hood design



Then to cool down the cylinders air charge, installed and tested water/methanol injection

Installing Water/Methanol

Also designed and made a cold air box so intake only received low outside air




Then I went to the ass end and first looked at the so-called tranny cooler, I tested and sucked
so I went with a dual split core cooler with thermostat controlled fan and using 2 pumps cool the M6 tranny and transaxle




So my points are if wanting best engine performance long term is multi ways to making it happen

Let's Go Racing, Boys !

 

[62 C1]

I wouldn't remove the thermostat otherwise it is going to take longer to come up to running temperature. I run a 383 stroker built to a fast street spec with a reasonably aggressive 277/286 cam. The radiator is a DeWitts aftermarket which has the flap system on the back so the faster you are going the more air goes through the rad plus a big fan on the back that is set to cut in at 180 deg. It all works pretty well together plus the Evans 180.

 

[62 C1]

and I run a 180 deg thermostat. Based on my gauge I am usually in the 170-190 range depend how I am driving/weather/traffic.

 

[teamzr1]

I wouldn't remove the thermostat otherwise it is going to take longer to come up to running temperature. I run a 383 stroker built to a fast street spec with a reasonably aggressive 277/286 cam. The radiator is a DeWitts aftermarket which has the flap system on the back so the faster you are going the more air goes through the rad plus a big fan on the back that is set to cut in at 180 deg. It all works pretty well together plus the Evans 180.

Good point
And worse with mid 1990s and newer MYs when there is an engine controller as it will stay in an open loop mode longer until coolant gets at least 140 F deg and ignores all the feedback sensors until finally getting hot enough to go closed loop
In most cases, that is in speed density mode and a richer AFR which is not the best case, so there is zero positive in running no Tstat.