View Full Version : Spitfire Spitfire overheating or not? Need advice!

05-11-2005, 09:44 PM
Hello, I am new to the Triumph world and need a little help. I have a 1975 spitfire that is in good shape now (at least I think it is) but, the guages show that it runs near hot after I drive it about 10-15 miles. When I turn it off, it does not boil over, hiss, or pop but I just can't get comfortable thinking it is a guage issue. I have done the following so far to address the heating issue:

1) took out the thermostate in case it was faulty since a thermostate can restrict water. Thought being without one there is nothing to cut off water supply.
2) drained the coolant and put in a new 50/50 mixture of Preston coolant/antifreeze.
3) verified that the fan and belts are functioning (appear to be)
4) water pump doesn't vibrate or leak
5) checked to make sure the "shrouds" around the radiator are properly in place and they are.

What else could it be??? Does the large license plate mounting cut off air? Do I need to put something else like "wetter water" from Redline in it? ANy help would be appreciated. Thanks, <font color="blue"> </font> from the newbie.

05-11-2005, 11:33 PM
first of all I'd stick a thermometer in it and see what the temperature actually is. Anything from a candy thermometer to a fancy infared deal from Radio Shack.

That will tell you right away if it is a guage problem.

05-12-2005, 12:00 AM
I see a couple problems immediately:

1) Am I correct in reading that you have NOTHING in the thermostat housing now? That would be a BAD thing. The thermostat not only acts as a valve, but also as an orifice plate, which creates a pressure drop across it. This change in pressure is a restriction to the flow, which helps keep the coolant in the engine long enough to pick up heat. If you remove the thermostat you are supposed to put in a plate like this (https://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=384389&amp;prmenbr=361) to restrict the flow and keep water in the engine long enough to heat up.

2)Also, drain that coolant. Ethylene glycol (antifreeze) LOWERS the cooling capacity of the fluid. The most you ever want to run is 70/30 water/antifreeze. For the summer (and if your car is kept in a heated garage) you can run 100% water. Do that before spending money on things like water wetter.

05-12-2005, 02:29 AM
The thing to keep in mind is that temperature sending units go bad. They lose their resistance (or increase their resistance, depending on the type.)

Definitely get a thermometer/pyrometer. A local mechanic can just shoot an infared at your thermostat housing pretty quickly and tell you if it's way off. (They shouldn't charge for this, it takes 15 seconds to do it, and it's a good way to get new clients.)