Overheating

[Robbo]

I use the stock 7lb cap and made sure to measure the stem too. Just to clarify, when i had a similar issue, some members helped me identify if it was overheating or just running hot. In the summer i had to get used to running hot in various situations but it did not overheat. If the timing and mix are set, look to the cooling system and the posts have the factors to look for. Careful on rhe pressure though, adding that much to a cooling system that is not operating properly will not help. New thermostat, get the air out of the system, check for gases or bubbles, identify if a 2 or 3 core rad (3 is more efficient), flush and check for clog or sediment and check the pressure of the cooling system, use at least 50-50 water-antifreeze mix are all good first simple steps and especially dont assume the guage is correct (unless you are in fact overheating then its probably right Good luck!

 

[Series V Susan]

The first step is to decide if you're chasing a temperature management issue, or a temperature measurement issue.

@Ken - I am also experiencing the joy of watching my temp gauge peg while driving - I spend more time watching the gauge than the road. A survey of mechanic friends says I have a blown head gasket but I'm not convinced. (Like I know... hahahaha) Head gasket replacement is next on the list unless the situation resolves itself in another manner. So I've been reading the forum for clues.

Your comments have me thinking; How do I check the actual temperature of the coolant fluid while running? I don't trust the gauge or anything else on the car as she sat for 30+ years until I got her running early this month. I put in a new summer thermostat from SS, all new hoses, new heater core & had the radiator re-cored by a local shop that does most of the British work in town and a new 7 lb cap also from SS. I am running just water in the system now because I am frequently draining the radiator to check for oil in the water as she blew a freeze plug while sitting and we were worried about a cracked block, (no sign of water in oil OR oil in water so far so I think that worry is behind me). I checked the system pressure yesterday at the cap and she holds at 7 lb no problem. But where can I get a tool to measure the actual running temp? What kind of tool is it?

I was also losing fluid but I think that was a faulty heater valve, I have now bypassed the valve and the heater is on full blast all the time now.

I will stick my head under the dash today and see if I can tell where the temp gauge ground wire is and what condition it's in.

 

[RootesRacer]

best way to tell is to get an infrared thermometer and point it at the top tank on the radiator (straight at it) at the lowest position on the tank which is where the water will be.

The top tank should be very close to the same temp as the coolant at the temp sensor.

You can also measure the temp of the core from the front of the rad but airflow will make this far less accurate.

 

[mikephillips]

There are infrared devices that can be pointed at the engine and radiator to get temp readings. Your garage probably has one or you can get an inexpensive on at a place like Harbor Freight. One thing you can do as well, when it's pegged stop and open the hood. If it's really running that hot you should feel it standing there as it'll be abnormally warm. If it feels like when you open the hood on your daily driver, then it's more likely a fault with the temp circuit.

You mentioned they said a blow head gasket. Quick checks for that are,
1 water streaks on the block outside, blown to the outside
2 water in the oil or a creamy substance in the valve cover, blown to the inside
3 water loss in both cases above plus, white smoke from the exhaust from
water in the cylinders.

Note though that all these could also mean a cracked block or head.

As for the gauge, grounds with a black wire running from gauge to gauge and attached to the body behind the dash, grounds all the gauges. Green wire from a small metal box to the temp and fuel gauges, this is the power supply. And a green with blue wire going to the sender at the front of the head.

 

[Bill Blue]

Susan, a more accurate method is to insert a candy or meat thermometer into a cold radiator. Be sure it has plenty of water in it. Start the engine and when water can be seen circulating, compare the gauge reading with the thermometer. Not as trick, but way more dependable!

Bill