401 Cooling Help Needed

Discussion in 'The Bench' started by Hodgepodge75, Sep 4, 2014.

  1. Hodgepodge75

    Hodgepodge75 Member

    Hey all,

    I have a 63 Wildcat with A/C and had been driving it around for about three months with absolutely no problems. Then I got an exhaust system installed, as it had none before, and on the way home from the mechanics my car overheated. Apparently to the point where not only did it puke coolant everywhere but the radiator itslef now has a leak in it somewhere. It is a Harrison radiator and I don't know how old it is but it hasn't been driving around for the past twenty years or so. Either way, I need a new radiator and I was hoping to upgrade, I didn't know if I also needed a new water pump or what I would even get as an upgrade for that. Lastly I've been watching my fan and it seems like it's a little wobbly. Like it's loose but the belts are keeping it in place. I didn't know if it was supposed to do that or not. I apologize for my ignorance. This is my first car and my first real experience of any actual hands on work so I'm learning something new with every new problem I have to fix. If anyone has a question ask away, I'll answer what I can.
  2. John Codman

    John Codman Platinum Level Contributor

    I wonder if the overheating was a cause of the radiator leak or an effect of it? If the car didn't overheat before (the exhaust installation) and does now, it's either a coincidence or the installers damaged something. The fan should not wobble. I don't remember if you have a clutch type fan or not, but you need to determine whether the fan clutch is bad or if it's a water pump bearing that's loose. If the fan is loose but the pulley is not, it's the fan clutch - easy to replace. If the pulley is floppy, then it's the water pump. Either way, be aware that a total failure of either part can cost you a radiator if the fan gets loose and chops it's way through the core. This is the type of issue that requires immediate attention. If you do replace the radiator, don't do it on the cheap. Install the biggest radiator that will fit. Most of those older GM radiators were available in two row, three row, and four row cores. Get a four row.
  3. Hodgepodge75

    Hodgepodge75 Member

    Any idea on specific radiators that might fit? I was going to replace the water pump either way, so I should be able to get a better look at the problem once the radiator is out.
  4. John Codman

    John Codman Platinum Level Contributor

    Make sure that you get an AC water pump - there are more fins on the impeller then on the standard pump. I have not researched radiators for that particular car, but some of the guys swear by the new aluminum radiators that are custom-made for whatever installation that you require - and are priced to match. I would just find and check with a good radiator shop and get an idea of what is available. Perhaps someone makes a conventional core that will fit your tanks.
  5. Hodgepodge75

    Hodgepodge75 Member

    Thanks for the advice! I do plan on going aluminum for the radiator as well. I'll put a call in, see what I can find.
  6. yachtsmanbill

    yachtsmanbill Well-Known Member

    Co-incidents are weird, but tend to happen on older stuff. If you can swing it, buy a radiator test pump with a gage on it. You can do some diagnosing with a cold non running engine. You mention the fan wobble and a leak. "Generally" theres a weep hole on the bottom of the water pump. Its a tell tale to let you know when the mechanical seal is leaking. If the bearings in the pump are going, the seal is taking a beating and maybe leaking.
    The other part of the wobble may be the fan clutch; that's still gonna cause undue stress on the pump. I had a shaft break doing a tune up and it took out the radiator, shroud, clutch and fan when it let go. Just a freak failure I guess. That was the third day I owned that particular 1970 original owner GS 455. It was an expensive tune up to say the least!
    Theres really no way to examine the pump shaft short of a teardown and NDT (magnaflux) job on it and by then you be past what a new pump will cost, if you can still get one for that.
    If you wanna PM me, I have a contact now in Waterford, Wi. that really knows his Buick stuff. He can probably tell you at a moments notice what you've got and what to expect. Bill in Two Rivers, Wi... BTW... welcome aboard!
  7. John Codman

    John Codman Platinum Level Contributor

    I got a new ac water pump for a '66 425 from Car Quest. It took three tries to get the correct pump, but they finally came through, and the pump has worked fine for years.
  8. chriswildcat

    chriswildcat 63 Wildcat conv.


    The 63's Non A/C cars use a 4-blade fan with no clutch. The A/C cars had the 5-blade fan with clutch and a shroud. The shrouds are extremely brittle and most are in pieces. C.A.R.S. in NJ may reproduce them, have not had a reason to check that in a while.

    I have talked about this before on the board. The A/C and non A/C cars used the same amount of rows in the radiator. Only difference between the two radiators is the inlet neck on the top tank (straight vs. 90 degree). Buick engineers knew what they were doing when they designed the radiators. three row radiator works. Any good radiator shop can recore your existing radiator, provided that the tanks are in good condition.

    Check the pump, thermostat and hoses. And I agree, go for an A/C water pump because it has a 5 blade impeller (vs. 3 on non-A/C).

    The biggest thing that improved overall cooling in my 63 Cat was having the motor rebuilt. I can only assume that there was 50 years of rust, crud and who knows what else sitting at the bottom to the water jacket. You can always try a coolant system flush, can't hurt.

    Just my two cents.

  9. John Codman

    John Codman Platinum Level Contributor

    I also recommend cleaning the cooling system. I would do it before you replace the radiator. I don't know whether it is still available, but I think that DuPont #7 cooling system cleaner did the best job. It contained some pellets that I suspect are some kind of acid, and a smaller amount of neutralizer which is probably baking soda. Follow the directions exactly if you can find the stuff. Do bear in mind that if you have any marginal components in the cooling system (think heater core) that any cleaning system may damage them. Don't blame the cleaner. Be grateful that you found the problem at a time when it was (relatively) easy to fix and not on the road.
    On a separate - sort of - note, many years ago we had a Dodge truck in the shop for overheating. The 318 V8 had a filthy cooling system - probably the worst I have ever seen. Everything that could be wrong with it was. We recored the radiator, replaced the heater core and hoses, replaced the partially-dissolved thermostat, replaced the water pump on general principle, and knocked out all of the core plugs (which necessitated the removal of the engine). The block was filled with rusty sludge to above the level of the core plugs - most of which were seeping. The truck was about ten years old and had never had any cooling system service. We had to physically scoop the sludge out of the engine with an old spoon, then used high-pressure water to get the crud out of the block. A couple of coolant changes over the years would have prevented what I'm sure was a very big bill.

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