The Stovebolt Site Forums The Shop Area General Truck Talk Hot 235...Help Please

Over the weekend I fixed the temperature gauge in my 61. All I had to do was put in a new sending unit and hook the wire up.

Anyway, here is my concern:

- When the truck is at "operating" temperature the gauge reads about half an inch under "Hot."

The temp gauge is a half sweep, H-->C type gauge. This seems to be too hot? I do know that I have some sort of radiator issue, is this too hot to run it? I have been driving it with the gauge disconnected for 2 years. I just want to sort this bugger out.

I seem to have some sort of cooling deficiency and want to sort it out. The first thing I am thinking about doing is a coolant flush. I might need a new thermostat? Water pump? I am just not sure where to start. Any help would be much appreciated.

Thanks,

Kyle

I'd try a "known good" guage first to see if your old guage is reading properly before I started digging into stuff.

A thermostat is cheap and easy to replace. If you replace the thermostat, the one that comes out isn't neccesarily the temp you want to use. Go with what the factory recommended for your truck. Some people put a higher temp thermostat in thinking that the heater will throw more heat. They most likely have a plugged heater core. If the heater core is plugged, it is probable that the radiator is somewhat plugged too.

A water pump will usually start leaking before it goes altogether.

I saw a radiator that was plugged up on the "outside" with mud and bugs. It ran for years but overheated when under heavy load.

I think id go for the thermostat first, you can check these with a bowl of hot water but I just replace them 1st thing cause theyre cheap.

Water pump, on an old truck I had, the circulator was made of plastic. It had a crack in it, but not all the way through. Worked fine until about 30-45 minutes into it then it would expand and not circulate water. On a cooler day it would work on and off. Drove me crazy...

On an old f*rd of mine same prob, just under the red, I replaced everything I could think of to get it to cool down, Finally bought a fan shroud at a junk yard and that solved it, it was sucking air from all over and not actually pulling any through the radiator. And it was proper distance to the radiator.

I would keep an eye on the gauge while driving. Now on the freeway does it still do this? Or just parked? If you have to much antifreeze in it itll over heat also.

Good luck, Jeff

Thanks guys,

I am going to have to wait until next weekend to get it sorted out. But I think that I am on to it. I am going to do the thermostat cause it is cheap and easy. I know that the radiator needs to be flushed and maybe even rebuilt.

Builder- How hard is it to swap a heater core? Would this by itself be enough to overheat the truck?

Rustednuts- My 61 has no fan shroud, is this something that it needs?

Thanks guys, I am going to have to figure this one out.

Does anyone know the "proper" temp for my truck to operate at? 61 w/ 235ci.

Thanks again,

Kyle

The heater core shouldn't be too hard to replace but I can't say on your truck, but I don't think that alone would be enough to cause a serious overheating problem. Theoretically, it does help lower the temp of the coolant. I could be wrong, but I don't believe the heater core is your immediate problem.

Like I said, the first thing I would do is put a "known good" temp guage to see if your readings are correct. If your guage is faulty, you can replace the complete heating and cooling system and you could have the same problem.

Good point Rnuts on the plastic circulator.

We used to measure the real temperature with a spirit glass tube thermometer. dip it right in the coolent in radiator with the engine running. do not open the cap while hot. open cap and let the engine warm. a cooking themometer should work.

A 'known good' temp guage or maybe one of those infrared temp guns- My mechanic has one and he points it to the running engine to find out how hot it is (always hotter on the therm housing).

Heater core would cause problems if it was leaking, with the heat off some heating systems won't let water to the heater core, so I'm not sure that if it doesn't leak it could be a source of the problems.

Don't think your truck came with a shroud, but one could be added to improve cooling.

Another area might be the 'fan clutch' if you've got one. When those go sometimes the fan doesn't spin at all.

I always start by checking to see if the system is full and not airlocked. Then I check the water pump. If there is no leak at the pump and no way the hole is plugged with grease or excess silicone, then its on to the thermostat. Once that is changed, if it is still overheating. Its gotta be the radiator- Its easy to pull it and take it to a radiator shop to have it cleaned. Often you can have it recored for about $100. I'd check with Autozone onlinet (or whatever other FLAPS is close to you) to see how much the radiator is and if they can get it 'cause it might be cheaper to replace than recore if the recore gets up into the $150 range.

Forgot to mention the cap, that could be a problem too, and like the thermostat, is cheap to replace.

Another thing is the belt on the waterpump, I'm sure you've checked it, but if its loose that could contribue to overheating too.

if it does not read hot then why worry about it....why not take a little water out of the rad and let it idle and see what hot is on the gauge,,,, just a thought...........

Thanks guys,

I am not sure how I am gonna attack this one yet, but I have the beginings of a plan thanks to you. I think that the first thing to do is find a known working temp gauge, then thermostat and so on. I think that I might adapt a shroud to fit. Has anyone done this, tips? Thanks again.

Kyle

Most of these trucks didnt come with shrouds. It does help though, mines on an old beat to hell f*rd so it didnt matter what it looked like but it was just enough to do the trick.

Mine was off an older previous body style but bolted right up.

Good Luck, Jeff

It might be a bit more expensive, but the electric fan kits fit tight against the radiator and would cool better. Many have a shroud built in. It would also give a tiny bit more HP back.

Just a thought.

it's not that you have to replace the whole heater core
just get it rodded.
also
you can have the radiator shop use their heat gun, a devise that they can point to an object... engine or thermo housing or core and read that temp @ that precise spot

Just a thought Kyle, does your type of gauge have a voltage regualtor? I had one of thses fail a few years ago (on a different type of vehicle, admittedly) and it gave that type of fault.

just a thought and correct me if i am wrong but couldn't you use the wifes meat thermometer to check the antifreeze temp,or going to the mom and pop place and rent an infared digital readout thermometer,i bought one for 89 bucks and use it regularely to check piston temps and bearing temps..

If your coolant system requires a zero pressure cap, you could use any thermometer to check the temp of the coolant with the cap off.

If you have a pressurized coolant system, the pressure allows the coolant to have a higher boiling temperature. In that case I don't think any thermometer would be accurate to measure the operating temperature.

I took the radiator out of my 261 and had a rad shop clean it up for about $100 and it works fine. At their suggestion I put an 8 pound cap on it.... and so far so good.

I have the same rad in another vehicle in which I run a 400 HP 355 CID V8 and I took it in and had them rebuild it and add an extra core - for a cost of $400. It keeps my V8 cool - but it still doesn't like rush hour traffic.

Find the problem Fort Knox?

Builder - Thanks for checking back in, I have narrowed the prolem down to the radiator. I think that I will take it in to the radiator shop and have them rebuild it, when I have the money that is.

Kyle