Hey, my 1970 has a guage for the temperature. I just recently bought the car, and the previous owner just rebuilt the engine. I'm troubleshooting my overheating problem, and I'm probably going to put in a new temperature sending unit (along with other things).

My question is: If the previous owner happened to put in a temperature sending unit for a light (not a guage), would it read always hot? The reason I ask, is that the second I turn on my mustang, the guage gradually climbes to "H" (it takes about 3-4 minutes).

I'm going to put a shroud on my fan, and replace my thermostat... but any other suggestions?

 

So is your engine actually overheating (have you temped it?)? Maybe the light is informing you too much. Get the right sending unit and go from there.

 

an easy way to chech the temp is i use a cooking thermometer or some other kind and stick it in the radiator, that wont give you the exact reading that your temp gauge does cause its located on the engine itselfbut it should give you a reading that is maybe 5-10 degrees off and it would give you a good idea, im still battleing with my heating problem and ive done all the steps you've talked about and mine is still running hot, so good luck lucas

 

Here's the deal. If when the engine was rebuilt the builder went to an auto parts store and bought a temp sending unit for a 70 Mustang, chances are he bought the wrong one. This happenned to me many years ago. For some reason when you buy the part ,they sell you a sending unit that supposedly works but doesn't. It gives a hot reading. The new sending unit is also larger then the original. The threads are the same, but the body is wider. You need to go to Ford or order the correct sending unit for your year and motor in order to get the exact replacement. BTW, I should add that this was specific to my 351 Windsor motor. Evidently over the years of Windsor production, they have associated a certain part number for the sender and thats what many a parts store goes by. Make sure to get the specific model year/motor sending unit and it will work fine.

Another weird scenario pertains to my FMX transmission. If you order the pan gasket and filter for the tranny, you will not get the correct one. You need to order the gasket and filter seperate in order to get the correct parts. The gasket is determined by the number of bolt holes in the pan. If you ask for the 1970 FMX kit you get a gasket that is not the same and the filter is way to big. Buy them from the same counter seperate and you get the correct parts.

 

There is definently different part number senders between light and gauge cars for your yr. My Cal mustang catalog shows a base PN of 10884 and either the "c" version with gauges and the "d" version with lights. Also, the previous post about verifying your temp with a thermo is a good idea since going to full hot in 3-4 minutes is not a normal event.

 

You have the wrong sending unit in there. Get one specifically for the real gauge and not the idiot light.

 

What is the best way to verify the temperature in the radiator without it boiling over? Do you just turn on the car with the thermostat in the radiator already... and just let it run till it gets up to temp?

Also, what is the best way to verify the temperature on the block?

 

bodyputtyless,

You're right so far. I just bought a $4.99 sending unit from AutoZone and it red hotter faster than my existing sending unit.

If I were to order a new sending unit from "Cal Mustang" or "NPD" or "Mustang Depot"... is there a way to make sure it is the correct sending unit from Ford? Or do I actually have to go to a Ford dealership to buy this part?

 

yeah when the car is cool pop the cap and stick the thermometer in the rad and start it up, when the car reaches the 160, 180 or what ever your thermostat is, the thermostat will open and the car should start getting hot, hotter if its actually getting hot and not just the sending unit. its easier if you have a second person sitting in the car letting you know where the gauge is at in relation to the thermometer in the rad. if the thermometer in the rad starts reading 220ish or above you'll want to shut it off so it dont get too hot and overheat, then atleast you know that you have a cooling problem and go from there...

when i went thru and still going thru the heating problem with my car i when down to AutoZone and got the sending i paid 3.99 [sm=tongue.gif]but it seems to work alright but i dont have a gauge with numbers to see what is says in relation to the thermometer in the rad....

 

Does anybody know what the degrees are on the standard temperature guage? What does the "C" mean in degrees, and what does the "H" mean?

I changed my sending unit to a Motorcraft product, and my temp doesn't shoot straight up anymore, but it does stay just below the "H". I'm going to get a shroud now to hopefully help the situation.