1970 440 SixPack - excessive hot temps while driving + other temp Questions....

[72ls5fla]

hello ----

Sorry to ask these questions again - I searched the forums but could not find what I was hunting for....



Here is the situation..

Outside air temp is around 95, with moderate humidity.
AFter about 20-30 minutes of traffic driving the temp will climb to exactly in the middle of the guage.  If I am driving the car on the HWY it will slowly creep up to 75-80 percent of the gauge (seems like 215-220 range).

Slowing down will very slowly bring the temp back close to dead middle.   Sometimes the temp gauge will jump up a big notch and then return to its previous position.  But then even in town, it will start creeping up to 75% of the guage and I can't do anything to get it back down short of shutting down for 20 minutes.

When I turn the  car off there is a little fluid from the overflow - very small.
I can hear burping and gurgling at the uppper radiator hose - almost like it is boiling in the block.

Sometimes there is very little pressure then it builds up after 5-7 minutes of sitting.

The car has 4.10 dana - always runs higher RPMs.
I put a new fan clutch in the car - it is working.  It will pull air pretty hard through the radiator from 1800 -> 4000 rpm.
I put a 160* thermostat in th car.
The fan belt is adequately tighten - no slippage.
I have the timing set to 6-7 degrees advanced at idle.  The vac is hooked up to ported non manifold source on the center holley.
Mixture seems good - does not lean out.
I run 4 gallons of Sunoco 112 leaded with balance of 93 pump.


This has me stumped.
The car was restored around 7 years ago - but not by me.
I'm sure the engine was done at that time too.

I can't speak for the radiator - don't know if it was cleaned/boiled out.  It is the original 26" for the car.

Ideas ARE APPRECIATED.

I was going to take the radiator out and get a restoration core for it and have the old tanks etc...  put on it.
Will 4 row help over the stock 3 row?

Thanks
in advance....

Bill

[burdar]

There was a guy over on Moparts that had a similar problem.  The car ran a little hot anyway, but when he would get out on the open road(with more airflow) the car would overheat.

It turned out that he was sucking the lower radiator hose shut.  The hose didn't have a spring in it like the origonals did.  I don't thing parts store hoses come with springs anymore.  That's the first thing I would check.

Watch the hose while someone revs the engine.  If you don't have a spring inside the lower hose...install one.

Let us know what you find.  Good luck.

[72ls5fla]

i will check the hose later today.

I just went downstairs and started the car.  The thermo was still open.  The fuild travels quickly through the radiator.  As I increased the throttle, the fluid moved quicker.  I am guessing that there aren't clogs........

more to come....


***********************

chceked the lower hose - no spring....   ARGH!

Where can I get a spring?

[MEK-Dangerfield]

What size is your radiator? 22", or 26"?

[polarbear123]

 can't speak for the radiator - don't know if it was cleaned/boiled out.  It is the original 26" for the car.

[500Stroker]

Middle of the rallye gauge is 180 on my car.  3/4 is 195 so it's not as bad as you think it is.

 I just put a Champion 4 row aluminum and 6 blade fan with heavy duty fan clutch in mine.  On the highway to Ocean City, MD for a 3.5 hour drive last week my temp never went above 150.  Idling in traffic was 165 while it was 75 degrees out.  Prior to this upgrade the car ran 185 on the highway and 195 - 205 idling in traffic.

[MEK-Dangerfield]

That reminds me of another thing, how many blades does your fan have, and do you have a shroud?

[Strawdawg]

I would like more proof that it is overheating.  I don't have much faith in factory gauge "meaningfulness".  I am with Stroker above

[72ls5fla]

It has the correct 7 blade fan for the Super Track pack option.  The shroud is in place as well as all necessary seals.
It has the factory 26" radiator in the car.

The car never actually over heated - just runs very hot as per the factory gauge.   I asked a buddy for a infrared temp gun - after memorial day weekend I will check the temps and compare to where the needle is in the gauge.   It could be a faulty sending unit too -

If the gauge is off - its okay, i willl at least know it.

thanks for all the great suggestions.

[burdar]

No matter if it's running hot or not, you need to figure out why it gets hotter when you cruise down the highway.  If it gets hot, it should be at low speeds...not when you have a lot of airflow through the rad.

It's a well known issue with new rad hoses that they do not have springs in them.  The hoses can suck closed at higher cruise RPM, cutting off the flow.

Make sure you have a spring in the lower hose.

[Chryco Psycho]

I would install a 180* stat , is the fan on backwards [I see it all the time ], dial out the vacumm advance with an allen wrench & bring the initial timing up to 16* , make sure there is a spring inthe lower rad hose

[72ls5fla]

Once I get back from MemorialWeekend I will work on these changes.


BIG QUESTION----

Where can I get a replacement spring for the lower hose?  It is missing....

Thanks in advance-
bill

[Chryco Psycho]

I have just cut up 2 wire coat hangers & coiled them when I was missing the wire coil

[72ls5fla]

hey all --

some updates.
1. added a spring to the lower hose.
2.  put a hi-flow 180deg. thermostat in
3.  for the hell of it - added a bottle of WaterWetter.

drove the car around city/hwy
still has same heating issues.  I even changed the sendin unit.
the guage is showing very high in the range still.

ran over to a buddies place - shot the IR gun
upper tank 205
upper hose 210
lower hose - around 215-220
core - 180->195
water pump housing 225-230

put a thermometer in the upper tank - temps ran 190-200 in the coolant.

I think the radiator needs to be rodded out or recored-   I am taking it out this Saturday and having a shop here in town try rodding it firest.

[HP2]

General rule of thumb, overheating at low speed is airflow, overheating at high speed is water flow.  Water flow issue can be running to slow and absorbing too much heat or running too fast to allow the heat to disapate through the radiator core. Judging from the radiator core temp, I'd guess the coolant is moving too fast.

You don't mention pulleys, but sometimes the underdrive pulleys can spin too slow. If you have the stock ones still, then it could be a water pump impeller issue. Do you know how many blades are on the pump impeller?