UPDATE : blew the water pump, now over heating big time!

[resq302]

On the way to a show today with Dad's 69 GTX vert with the 440, he called me up and said that he was overheating and pulled off to the side of the road.  I met up with him and saw coolant flowing like a faucet was turned on from the lower part of the pump.  We had the car towed back home and swapped out the water pump with no problem.  What I saw that was strange was on the back (impeller) side of the pump, it seemed the seal / gasket had backed off and was being pushed out by a spring.  The water pump was the original dated one for the car so I figured the seal just gave up after 44+ years of use.  After I got the new pump installed, I took it for a short trip around the block and noticed the temp gauge rising very quickly after about a 5 minute drive.  I get back into Dad's driveway and shut the car off and it started puking coolant out of the overflow hose and you could hear the coolant boiling inside the radiator.

What would cause this?  I just put in a high flow Mr. Gasket thermostat which is supposed to fail in the open position.  When I put the engine and everything back together, I had the rad flow tested and it was flowing 20 gals per min which is what the factory radiator is rated for so I know that is fine.  The car also idled perfectly fine and had plenty of power so I am guessing a bad head gasket could be ruled out.  There is no oil in the coolant and no coolant in the oil nor the trans.

Something seems to be causing the engine to make more than 16 or 15 psi (whatever the factory cap is rated for).  I am kind of leaning towards the Mr. Gasket high flow stat going bad (again, been installed for 2 weeks! and ran perfectly fine last week when I tuned the timing and carb)

What is everyones thoughts?

Thanks,

Brian

[moparsr2fast]

  Here is a picture of a pump being rebuilt. This is with the new style seal installed..



Run it  with the radiator cap off. Look for bubbles flowing up thru the radiator. If you see none, cap it, run until it starts getting over warm. See if the upper hose feels really hard. If the hose is hard, but no bubbles, it is the thermostat. If there are bubbles, it still might be a head gasket, even without contamination  at the moment

[resq302]

Yeh, thats kind of what ours looked like only ours had the impeller on it.  The upper hose was hard and when I ran it the second time with the cap off, it did not seem to flow but all of a sudden started shooting up like a geiser.  I gotta say, as messy as it was, it did get some decent height!  You can also hear the water/coolant boiling inside the hose and rad so I am kind of leaning towards the t-stat being bad.  I did not observe any tiny bubbles like you would have with a bad head gasket.  Also, the nose of the car was elevated somewhat due to the sloped driveway leading up to the garage so I would assume if there was any air, it would have been let out if the thermostat was working.

Also, what is the new style seal that you talk about?  Ours looked like that but was the original dated water pump.  Maybe it is possible that it could have been rebuilt once before.

[moparsr2fast]

 Brian, I do not have access to the catalogue  at the moment, but it can be found in a big yellow McMaster Carr catalogue. The seal kit is a bit over $12.00

[Cooter]

Did you burp the air out before taking down the road Brian?

[resq302]

Cooter,

Prior to this, I had the car idling on an inclined slope before my Dad's garage when I was setting the timing and the carb.  I'd say it probably idled there for a good half hour, maybe 20 mins the least.  I would have imagined any air would have escaped during that time.  Although, I did not burb it this time after I replaced the water pump so there is a good chance that it still would have had air in the system.  My only concern is that it did that overflow / boil over 3 successive times.

[Cooter]

You say you messed with the timing?

[resq302]

Yes, I had the distributor out when I was cleaning up and repainting that section of the engine.  It is now back to where it was before.

[resq302]

Great news! Today while I was at my Dad's I started off with doing a pressure test on the cooling system with the Stant Pressure Tester I have. No drop in pressure so that told me that everything was pretty much good and reaffirmed my thought on the head gasket being good. I then drained the coolant and removed the lower hose to install a spring in there even though it was not collapsing before, I figured it couldn't hurt to put one in while I had the system drained. I then removed the thermostat and replaced the Mr. Gasket high flow thermostat with a Stant Super Stat. (prior to installing it, I had tested it in a pot of water on my stove to see when it opened up (opened up between 180-190) yesterday. After I reinstalled everything, I did the same test to the Mr. Gasket t-stat...... nothing! The thing wouldn't even open up in boiling water! I can say this, that is the last Mr. Gasket item I will ever own. Their quality seems to be horrible from what I have read on the web. Once I filled up the system to just above the tubes, I backed the car out of the garage and pulled the car up onto a set of ramps to raise the front end to get all of the air out of the system. Once the coolant was circulating in the rad neck, I topped it off to just above the baffle inside the upper rad tank. Since the road was wet, I just let the car idle for quite a while periodically checking the gauge on the dash as well as taking a reading with my infrared thermometer. The temp at the sending unit never went above 203. Keep in mind, this car never seemed to have a factory shroud installed as the original dated rad does not have those nuts for attaching the brackets to it which would mount the fan shroud. Either way, the gauge never went above the 11 o clock position and seemed to be just above the "warm" mark on the gauge. Looks like we lucked out again big time.