1970 V-6 heating questions

I rebuilt my V-6 while doing my frame off. I had it bored .10 over and everything was checked, cleaned or replaced during the build. I replaced the water pump with a brand new Flowkooler pump. I also had the radiater reconditioned.
My problem is the water temp stays at 180 degrees while crawling around on dirt roads or running around town with temps outside between 90-100 degrees. If I run the jeep down the freeway at 60-70 mph the temature runs up to 200-210 degrees. I'm only turning 2000-2500rpms at these speeds.
Anyone else out there having this problem? Any thoughts? Ideas?

 

What type of fan are you using? Electric or mechanical mounted to the water-pump?

Do you have a shroud around the fan?

and lastly, is the fan turning the right direction? Could be pushing towards the front, instead of pulling toward the rear.

 

Thermostat replaced?

 

I'm useing the original mecanical fan, no Shroud. It is pulling air and not pushing. New thermostat. I also have the factory 5 blade fan.

 

I would check the total advance on your timing. Should be about 32-36.

 

The missing shroud could be the cause. Had a pickup that was missing the shroud and it oveheated constantly until I put one on.

 

Pressure check your complete water system and then separately your pressure cap...........system should be around 16 lbs. A shroud for low speed is always a good Idea but at 60 + mph I doubt that would make much difference in air flow to the radiator.

 

Overheating is different from running an an optimum temperature.
Overheating would be sending the temp gauge to the top.
The modern cooling system will allow the vehicle to run within the parameters you have.
A 50/50 mix of coolant will go to at least 250 before boiling, when under pressure, which should be
14 psi for your system.
I pulled a 13 ft. travel trailer with a V6 Commando. Had the shroud and 7-blade fan. Did not overheat.
As long as you don't get the "old Faithful" effect, don't worry about it.

 

Conventional wisdom and experience will tell you that the technology in these engines won't live much past 220 degrees if reached on a regular basis. I would be in the camp of checking your timing, looking at the spark plugs as a read for being too lean at higher rpms.

 

To the point that tommycj brought up, and Daryl responded to, your engine should run near the thermostat set point ALL THE TIME. If the temperature goes much above that, you've run out of cooling reserve. The thermostat temperature is the set point for the engine - that's the temperature it should run at.

The OP got some good advice about timing and/or lean mixture - I would check that first.

Usually you have overheating problems at low speed or under a heavy load. On the highway, there should be lots of air pushed through the radiator, with or without a fan or fan shroud. So the conditions described by the OP are backwards from the usual scenario. This is why timing is suggested - the timing will change depending on engine speed and vacuum.

 

I'm all for checking timing , but I'm not so sure I would be looking for a lean plug condition as much as I would be looking for detonation . One does follow the other. Most engines when faced with excessive timing and a hotter than normal block and intake track , will sometimes ping and or detonate while also showing a noticeable loss of power during that event. Detonation is also not that easy to detect on the plug unless you know what to look for.

The fellow with the issues never mentioned any loss of power just the high temp @ 60-70 MPH........With only that to go on , I would be more inclined to think it's a cooling system issue?

Like Maybe,
Low Pressure in the system.
Head Gasket leaking Hot super heated combustion gases into the water.
Air in the system , thus causing cavitation at the pump impeller of the water at high RPM's
And also some of these high volume pumps, move water to quickly and sometimes do not allow the water to heat sink and do it's job.

Where is your temp sender located?

Just Guessing!

 

This should elicit some comment---
Where is your temperature sensor installed--front of intake or to the rear?
Early V-6 had the sensor in the front, owners complained of high temperatures, as per temp gauge.
Sensor placed to the rear, lower reading on heat gauge.
Still the same water, different temps depending on where reading is taken.

 

I'll submit a scenario:

The father of one of my friends growing up owned a Model T. Everything in it was original except the water pump. There was no water pump. Car came that way. Ran fine, temp never going very high. However, not having a pump bothered him so he located an original pump for the engine and installed it. Immediate over-heating. Worse the faster you drove. He pulled the pump and replaced it with the plate that was there when he got the car. No more over-heating. What was decided on this was that the pump pushed (or pulled) the coolant through the radiator faster than it would cool off, making the engine over-heat. With the plate in place, convection cooling maintained the engine temp at operating temperature, and the car was drivable.

Could be the same kinda thing here. The pump may be circulating the coolant faster than the radiator can cool it off.

 

The internet Blogs are full of unhappy folks with exactly the same problem your having with a FlowKooler water pump...........cools fine at low RPM and heats up at higher RPM.......Google it up and read what the folks have to say. Just might be your Problem?

 

I was thinking that the timing could be part of my problem. I originally timed the engine with a timing light, then as I was fine tuning it I just used a vacuum gauge. I'm pulling about 18 inches of vacuum. So I actually don't know where the timing is set.

 

Originally when I was fine tuning I had a little pinging so I backed off the timing and it went away. The moter has plenty of power, I ran it up HWY 88 all the was to Silver Lake and never lost any power pulling the hills. I was able to run up the grades at 55mph.
The sending unit is on the front of the intake manifold. (same as original set up).
i am wondering about my cap, I used the old cap and didn't replace it.
I have bled the cooling system 2 times. I'm pretty sure I have worked all the air out of system.
i have been wondering about the Flowkooler water pump. It is supposed to move the water at a higher rate, that's why it's working at the low speeds, and moving it to fastvatbthe higher speeds not allowing the water to Kool.

 

I looked up some reviews, your right, most complaints are the same as mine. I worked a 18hr shift today so I didn't get a chance to check the timing, I will do this prior to going to work tomorrow. This is to eliminate the timing as a problem. I still have the old water pump that is in usable shape so I think I'll put it back on and see I still have a problem. I'll update as I go.
This is why I like this forum! ......a wealth of Knowlege.

 

Go ahead and check that timing , always a good Idea. But I think you already answered your question about timing in the previous two posts............If you ran up to Silver lake , which is around 7500 ft and it ran as good as you say it did at that elevation.........it's doubtful that it would have done that with excessive timing in that thin air...........Of course there is always anomalies in any engines tune up when at different altitudes or temperatures..........Keep checking.

 

I'd say this is unlikely at 2,000 - 2,500 RPM with a reconditioned radiator, but I've seen stranger things:
A soft intake hose gets hot, and collapses under suction at sustained higher RPM. Should be easy to check when sitting still after the motor has fully warmed up.

 

Mine did the same thing ended up being a intake leak resealed and no more over heating