Ok I have changed the temp sending units and now the temp gauge works like it should but gets all the way on the hot mark when running. Flathead 8 is the engine so Julie said I should get a laser lite temp gun and check to see if it is really that hot and this is what I found out. I have not changed the new 160' therostats out yet they should be in tomorrow but with all the different temps I'm getting I don't know if they will make a difference or not.

temp sending unit on drivers side with the two connectors side reads 215' the one on the other side reads 266' don't know why they are so different in temp. Heads on the drivers side 182' and one on pass side is 164' but why I don't know. The radiaitor reads 180' at the top and about 176' at the middle but why I don't know. Oil pan is reading 177'. The exhaust on the drivers side reads 240' and the other pass side reads 236' The therostat housing on the drivers side reads 186' and the pass side reads 170'. Does this make any since at all with the temp all so different when the gauge reads hot.

I talked to Ken F2 on the phone and told him what all I have done to the truck and he said it sounds like the water pumps aren't putting enough water through the engine. They may be old and the four vain pumps and to pull one off to check if they are and if they are get the new type with six curved vain but that is quite an expence but if it will make the temp around the same I'm willing to change them out.

Another suggestion is to get a shroud to put on the radiator and I have read that it should reduce temp about 30'. If anyone has any other ideas I will listen and try.

Thanks for the responce in advance,
Larry Brauer
713-410-7481
braular@yahoo.com

 

It all makes sense. I'm not quite sure about that 266* - that seems to not match anything else

I'm no flathead expert, but to be honest, with the engine running at idle and the truck stopped, those temps don't seem excessive to me. It sounds like the engine is operating at right about 180* Drivers side is running a little warmer than the pasenger side.

With that 266* at the sender though, that would explain why it is reading so hot whether it is the analogue sender or the overtemp sender - either would send the gauge to "H" at 266*

I'm wondering if there is something impeding the collant flow around that sender? Some gunk or something it doesn't take much.

I'm sure the flathead guys will be here to analyze this. But I think you are very close to getting getting done with worrying about your temps.

Did you have fun with your new gun?

 

Oh yes we did have fun with the new gun but was concerned so most of the fun was taken out. What do you think I should try next get the new water pumps or pass on them. I have heard that to much water going through the engine can make it overheat also. Don't know if that is true or not. I am still stumped but at least I know the gauge works. Do you still think I should put a seperate reducer on the temp gauge? I have some but just haven't put it on as it is a pain getting under the dash and doing it. So far you have been right on the head about everything else.
Thanks so much for your time on this subject.

Larry Brauer
713-410-7481
braular@yahoo.com

 

Take the thermostats out completely and see what it runs at. Those are very high temperatures. What exhaust system do you have? Any chance it's plugged?

 

Both exhaust pipes are open I have checked that once before when it came up. Putting your hand over the end of the pipes and it feels like the same pressure coming out. I think those are very high temps too. I have two different pipes off both sides of the engine like a true dual system. The pipes go straight back off of the exhaust manifold. Any thought about putting on new water pumps?

Larry Brauer
713-410-7481
braular@yahoo.com

 

Hmmm Ok I'm wrong on the temps. Like I said I'm no flathead expert

If Ross says that's hot then it's hot! He's in the know!

Just out of curiosity, what should those readings be?

 

Ok Ross what should my next move be if I take out the therostats and check it with the gun again and it reads about the same thing? I will try and take them out tomorrow as I was going to change them to 180' instead of 160' like everyone says should be in it. I will let you know what the difference is if it changes anything before I put the 180's in.

Thanks
Larry Brauer
713-410-7481
braular@yahoo.com

 

I guess I'd take off the water pumps and have a look. The 4 or 6 vane thing isn't quite the big deal, IMO an engine that's got a good cooling system will run the same temps with either (on the street). You should get a shroud (make one). You aren't running a flex fan by any chance are you? How far behind the rad is the fan?

 

I am not running a flex fan it is a four blade fan and sits about three inches away from the radiator. I can feel the air moving through the radiator from the outside and feels like it has a good pull on air. This is driving me in the nut house trying to figure out what is wrong with this darn truck and the temp. Since there are two different water sending units would it make a difference what side the double prong was on. I talked to two different companies and they both said the two prong one went on the drivers side so that is where I put it.
Thanks for the feedback
Larry Brauer
713-410-7481
braular@yahoo.com

 

Doesn't matter which head it's in, it just changes which one's temp is shown on the gauge, as long as you wire them up correctly.

I looked at your temps again; what struck me the first time was the temp of the sending units. They are very hot, yet the heads, thermostat housings, and radiator aren't. I assume you shot the heads in the middle? I'd still like to see what it does with no thermostats -- Yank 'em out and see what happens...

 

You mentioned reducers on your gauge. Are you running 12 volts through a 6 volt gauge and sending units? That would explain the freakish temp readings. I'll guarantee you you aren't running 266F.

The radiator is supposed to be hotter at the top than the middle or bottom. That's how a radiator works. It dissapates, or "radiates", the heat as the water flows down through it.

I agree that, ideally, both sides of the engine would be the same temperature. But neither side is anywhere near critically hot, imo. In fact, it seems to be a pretty normal operating temperature. It could be something as simple as one water pump being more efficient than the other. A 15 degree spread seems a little odd, to me, but probably explanable by a flattie expert.

Your oil temp looks good, as does your exhaust. I still say ditch your stock temp gauge and put in an aftermarket mechanical, or maybe two. You're way overthinking this deal. My 2c.

 

Will do and we did shoot the head in the middle. I know it struck me strange too with the sending units being so hot. They are 6 volt senders in now I did have 12 volt senders in but was told to change them to 6 volt by Julie so I did. I think everything is wired up correctly at least we went by the ez wire diagrams and with the help of Julie. Gauge is resting on hot when key is not on and when key is on it goes to cold then climbs back up all the way to hot.
Larry Brauer
713-410-7481
braular@yahoo.com

 

I am running a 12 volt system with a reducer on the gauges and yes the water sending units are 6 volts. I had 12 volt senders in but was told to change them as I had the same problem as I am having now. Nothing has changed by changing the sending units. Has to be something else that is causing the problem. Everyone says to put a shroud on the radiator and it will make a difference of about 30% cooler. I don't know if that is true or not but I am willing to try anything at this point. Taking the thermostats out tomorrow and see with the laser heat gun if that makes any difference or not. Also going to check to see if the therostats are opening at the temp they should in a pot of water on the stove with the gun.

 

OK, but are you running 12 volts through them or not?

 

I would supose I am running 6 volts to them as the wire comes of the gauge which is reduced to 6 volts with a reducer. I mean all the other gauges work just fine and are correct gas, volt gauge, oil pressure gauge. Makes no since to me.