1960 389 pontiiac over heating problems... HELP

548690 is the cast # on the water pump housing with the 4 bolt pump. I have covered all the bases several times, as well as my friends.the motor cast #s indicate 1960 block and heads with an Edelbrock p22 intake. It just acts like its not pumping, but the impeller spins free, solid to the shaft, with not a lot of wear. the motor gets hot and the rad stays cool , seems like no flow. Ring any bells?

 

I am not sure about the earlier pontiacs but is there the divider plate in the water pump? If so what is the clearance from the water pump impellar to the divider? My 455 had this issue when I bought it and the PO forgot to reinstall the plate.

 

The early Ponchos like yours do not have a divider plate. Motor hot and rad cool sure sounds like a pump. Does the heater not blow hot either? That's a good water pump test. I've seen pumps that you couldn't spin the impeller seperate from the pulley by hand but the heater didn't work so we changed pumps and it was problem solved. I assume the thermostat has been covered already. Does your temp gauge shoot up or light come on?

 

Have you tried a new pump? We had a customers car do the same thing. It had no heat from the heater. The impeller seemed solid on the shaft but changing the pump cured it. I put the old pump in boiling water for a couple of minutes, picked it up and the impeller fell off.

You could mark the shaft and impeller to see if it moves. I think the shaft is hardened or you could drill and pin it. Looks like a pump is about $50.

 

Is there a spring in the lower radiator hose to keep it from collapsing?

 

cast impeller, no heater, its in a model A, heater port on the pump housing is plugged, I gutted the thermostat to eliminate it as a culprit. spring in the lower hose. tried another pump I had on the shelf, no change. Thanks for the input, any more?

 

distributor advance working correctly? retarded timing will cause OH.

 

My 421 would run hot until I installed a thermostat and hooked up the vacuum advance

 

I'd get a cheap infrared remote temp gun to find out where the temps change. That should help in locating your problem.

 

Why do you say it's overheating? Gauge or light say so or does it actually cook over when you shut it off? I grew up working in Dad's radiator shop and we saw lots of times where it was just a faulty sending unit.

Is this something you just put together or a new problem on something you have been driving?

 

Ask this question over at the Performance Years website, or search the archives.

Here's the link to the 61 and older section.

http://forums.performanceyears.com/forums/forumdisplay.php?f=426


Greg

 

I have a '60 Pontiac and been running a Weiand intake now for over two years and this car is my daily. The two front water ports were circular, plugging the most forward one. I also shaped the other to match the "L" shape. No problems in overheating, especially this summer. The water pumper to get is the OEM type or NOS, I've been told that the after market ones being made are not worth it and don't perform. What temp thermostat you using?

Ken

Note: older pic when I was putting it together back in 2008

 

[QUOTE=dubcee;6946602 the motor gets hot and the rad stays cool , seems like no flow. Ring any bells?[/QUOTE

ding ding ding
No or insufficient flow.

Changed pump & no change
If that was a good pump then its not a pump problem.

Spring in lower hose ,
That one is the easiest.

Tstat removed
Second easiest.

Check for flow thru block and radiator.
Head gaskets , intake gaskets , blocking coolant would be a good guess.

Put a loop on the heater in/out let and see if that gets warm.
If it Warms then look for radiator obstruction.

 

Just put it together, new radiator, temp gun and gauge show same temp at the manifold, head and block climb to220+ the intake and rad at 130, shut it down and it boils over, starts blowing out cool water then changes to hot! It acts like no flow from the pump.

 

Is the pump spinning the correct direction? You could try pulling the bottom rad hose and see if water will run through the core, maybe a defective core?

 

Wow dubcee, sounds like you have really covered all the bases and that you definetly have a lack of flow problem.
I suggest going with gregneun's idea of going over to the Pontiac forum. There might be gasket differences from early to late motors I'm not aware of and you got the wrong ones. Check with guys that deal with that era Pontiac.

 

Where did you buy the pump?And it was asked before whether it has a stamped steel or cast iron impeller.There were some rebuilt pumps floating around awhile back that had an incorrect impeller installed.The vanes faced the wrong direction and would not flow water properly.
Best bet is to pull the pump and compare it with your old one if you still have it.Sounds like your problem.

EDIT:The bogus pumps had a stamped steel impeller.

 

Two bad pumps ? I suppose its possible

 

You'll most likely find this useful over the next few days.
http://www.pontiacsafari.com/EngineCooling/index.htm

 

The cast vs stamped mostly applies only to the 11 bolt water pumps, and also to the 4 bolt pumps but not as important. The reverse cooled 55-59 engines used the cast impellar, and the 60 and up 4 bolt pumps use the stamped. The direction vanes are differant, but can be switched around and still work since the pumps both turn the same direction.

Does the bypass hose from the timing cover to intake get hot? Is this something you just put together? Possibly an airlock in the cooling system? I run the 60 cover set up on my 66 389 and don't have any problems at all with the stamped impeller.

 

When I went to a P22, with my 389 with miss matched parts that runs good. I was starting to install the P22 and a friend said you have to switch soft plugs on the manifold, open one up and close the other this gives you the option of selecting what year heads you are using and allows water to circulate.
These water holes are on the intake manifold near the front on the surface that bolts to the heads, a set on each side.
I looked for a picture of the under side of a P22 but no luck that shows the soft plugs that I'm talking about.
I am no expert on Pontiac's but my engine runs and water circulates.
I may be way off base I make a lot more mistakes than most but just my personal experience so good luck.

 

Might want to take a really good look at the gaskets used between the block and front cover. Later gaskets had the coolant holes in a different place than the earlier ones

 

I had the same problem with a p-22, they will fit 55-64, mine had the soft plug in the wrong hole similar to what 30panel described

 

Just got home from work, I have a little customer work to do in the shop, then its tear down time! Ill let you know what I find, Thanks for all the input guys.

 

Here' s a pic of what these guys are talking about. This is a Offy manifold but same deal with the 2 holes towards the front of the intake...

I would also be interested to know what set of holes are used per year set up.

 

It looks like the block at some time has been drilled for gusher heads? Why? Plugging it now!

 

How are things going ?

 

I plugged the early "gusher holes, some one drilled, and put it back together. I got a little better flow, and more consistent temp, but the problem is still there, it ran a while longer before the over temp this time. Now i am going to pull the intake, and check the cross over. Does any one know if the cross over in the front of the intake is the only one? I feel like there should be one at the back of the heads.

 

Did you muttle thru that link I posted on the first page?

 

Factory 59-60 intakes only have a crossover at the front. I could take some pictures of the mating flanges of mine next time I am in the storage unit, if you want.