Temperature Climbs When in Stop & Go Traffic

[focodave]

Looks "normal" to me.
I think you solved your problem(s).
Beautiful dash, by the way.....

[joelittel]

Thanks on the dash. C & G Woodcraft made it for me.

[vandor]

If it does not go above that then you are fine.

[agarair]

Sounds like your cooling issue is solved, I just wanted to relate an occurrence I had many years ago. When my 71 spider was only three years old and I was living in New Hampshire (think very cold!) I had a cooling issue that seemed quite strange at the time. When driving in stop and go traffic with the outside temp in the teens, the heat hand would go up at a stop light, but would come down if I held the engine at about 1500 RPM. The other odd thing - the air coming out of the heater would turn very cold at the same time the engine temp went up. This blew my mind, I just couldn't understand that at the time. Dealer suggested changing the water pump, which I did to no avail, I checked all the fittings, made sure she was properly burped, still had the problem. Then one day it occurred to me, the system will not circulate water if it cannot build up pressure . . . replaced the radiator cap and fixed the problem.

[DogRocker]

I found this older, helpful thread after reading many other temp related threads. I just thought I'd give it a bump. My car is doing exactly the same thing as what's seen in the previous pics. In addition, when I turn the lights off, the temp drops slightly. Thanks.

[TX82FIAT]

The temp does not actually change when you turn the lights off. The circuits on this car do not all have independent relays and turning on and off items that draw more amps has an effect on the temp sensors reading but not the actual temp. As this post discusses. A methodical approach should be taking with a heat issue. I can be many things starting off with the most common air bubble in the system that needs to be burped, failed coolant switch, water pump, radiator clog all the way up to a head gasket issue. Even a small leak over time will lead to air being drawn in the system.

[dinghyguy]

I found when i changed all the dash lights to LED's and cleaned all the contacts to both the lights and the instruments with a Dremel wire brush and used some dielectric grease the temp variation with lights on or off vanished. Oh and you can see the gauges at night too! I have posted pix of before and after if you are interested.
I also put relays in the system for the lights, but that did no make any difference to the gauge issue (i did that first).
cheers
Dinghyguy
(out of the dungeon and finally into the sunshine)

[DogRocker]

After fiddling with the cooling issue over several weeks I feel lucky to be where it is now (which is similar behavior seen by the OP and shown in previously posted pics in this thread). In my 81 FI car the head gasket was replaced, a flush kit was installed on the heater hose (a must), the radiator flushed, a block mounted thermostat was removed and replaced with the stock, external type with associated hoses (this made the biggest difference), the fan switch was bad so it got replaced, and many attempts at burping followed. Just for fun I mounted a fan switch under the dash. Along with that I rigged an LED to indicate when the fan turns on (hard to hear the fan running in traffic with the top down). It still does that creep up in traffic.

I noticed that the radiator is smushed in a little at the bottom like someone tried to use that spot as a jack point. I'm sure that doesn't help flow. Also, the fan mount bracket is digging into the backside of the radiator a bit. The next chunk of money should probably go to a new radiator, ...and water pump, hoses, and stat since they're old and might as well once you drain the system.

I have bypass relays for just about everything that draws significant current...headlights, starter, wipers, horn. I recently got all the the stock dash lights to work in the car. After cleaning contacts and fixing a broken ground wire it took several attempts to get the dash back in place without the speedo cable falling off or one or more lights popping out of its socket when wiggling the dash back in place. I should have put dielectric grease but didn't. Next time I'm in there. I noticed that the Voltage to the dash lights was a bit low. I'm thinking the rheostat and grounds need to be checked next...on another day. I have dash lights although dim, and that makes me happy.

The weather is good now, so the car will be driven.

[DieselSpider]

I have an old fashioned Sun Capillary Tube temperature gauge and that eliminated the electrical issue for me.

Since coolant absolutely must be flushed and replaced every 2 years especially in an older mixed metal system I flush the system with a 60/40 mix of distilled water and white vinegar very shortly after I get a new to me vehicle before replacing the thermostat along with refilling with fresh coolant and distilled water. Too many times there are problems after a head gasket replacement because the mechanic failed to flush out the system properly afterwards to get rid of the buildup of chlorides and other deposits and an oil scum that was coating the cooling passages in the block insulating it from the coolant. Many also fail to verify the condition of the water pump impeller which can also be considered suspect on an old car with problems.

The stock fan thermostat in the bottom of the radiator if it looks too badly stuck there gets replaced with a $20 universal adjustable one with its capillary pickup mounted near the top of the radiator so I do not take a chance on damaging the bottom of the radiator.

The electric cooling fan will be removed, cleaned up and the sintered bronze bearings soaked in Dexron I or II transmission fluid before reassembling.

After the system is burped, if there is a problem with temperature creep when sitting in traffic or running at highway speeds I will add either Lucas Super Coolant or RedLine Water Wetter additive after verifying that the fuel system is not running lean on a gas engine or rich on a diesel.

I live in Tropical Sunny Florida where cooling systems have to be in top notch condition to deal with the heat and humidity.

[DogRocker]

I added some Redline Wetter Water resulting in a slight improvement. Maybe. Radiator, new hoses/clamps, t-stat, even water pump might do the trick.