View Full Version : Running hot

Trevor Triumph
07-13-2009, 01:31 AM
My '64 Spitfire with a 1296 engine will run cool for several trips, then boil over. This last time may be associated with the temperature here- 100 degrees or more. I don't remember the last time a replaced engine coolant. If it has been two years or more, is it time?

Andrew Mace
07-13-2009, 08:49 AM
In a word: yes! And make sure to thoroughly flush the block as well as the radiator.

07-13-2009, 04:45 PM
Andy's right!
change it. look in your rad to see if there is build up (if there is, get the rad boiled out). check your themostat to see if it is working ok (you have to take it out and test it in boiling water and cold water to see that it is moving ok).And, the most important thing, after you make sure your block/head/rad is clean and/or flushed is: MAKE sure to get all the air out. Air will trap in the high points. run the car with the heater on hot (if you have one). Go for a drive at night, let sit over night and check the level the next morning.
I usually fill the system with 50/50 glycol and run the motor with the cap off till it warms up enough for the thermostat to open and add more coolant as the level drops (once the thermostat opens, you may need to shut the engine off fairly soon). You can't do this for too long or rev it too much with the rad cap off when it heats up. If you have an overflow bottle, make sure it has fluid in it so that when the motor cools down it will suck fluid back in to the rad.
If you have an electric fan, make sure it is working ok. I don't know about spits, but some of the tr's do not take a standard rad cap. Get your cap checked if it is old.
Never use tap water. you can get demineralized water at the drug store by the gallon.Red line water wetter helps also. If you don't know the last time the rad was boiled out, you might want to do it anyways, I would if i lived in arizona. While you are at it, check all your hoses. If they seem soft compared to new or seem rock hard, replace them. I like to do all hoses throughout if i find a bad one, unless it's not usual wear and tear. I replace the works every 10 years and have never had problems.

07-13-2009, 05:01 PM
I don't remember the last time a replaced engine coolant. If it has been two years or more, is it time?

Honestly any decent coolant (prestone 50/50 ready-mix, for example) can go 5 years / 120,000 miles easy as long as theres no other engine problems. You can flush the coolant as often as you want. But 2 years don't seem bad to me.

07-13-2009, 05:08 PM
but he is having problems and is not sure when it was last changed.

07-15-2009, 08:57 AM
Most auto stores (up here anyhow) sell glycol AntiFreeze testers for about $10.00 ($8.99 US $'s)these are a syphoning bulb with a radius tank and needle that will tell you the condition, mix or efficiency of your AF / H2O mix

07-15-2009, 10:46 AM
Yes, they tell you the glycol mix, BUT, what they don't tell you is the amount of contaminents in the mix (unfortunatly). Most coolant is good for a very, very long time, except for the increasing contaminent level from internal corrosion, leaking seals, dirt, tap water minerals (someone usually puts in tap water if they have a boil over) etc. So that is why it is changed, more than any other reason.

07-15-2009, 01:19 PM
The main reason for changing it IMO is because the additive that suppresses dissimilar metal corrosion gets exhausted over time, and no longer protects the lead/tin solder inside the brass radiator, and the aluminum thermostat housing bolted to the iron block (if you have one). (Not sure about a Spit, but the TR2-4A use an aluminum housing, and I have seen them fall apart due to corrosion from not keeping the coolant changed.)