1956 Buick Overheating Problem. Help?

[Guest]

My 1956 Buick Roadmaster overheats (pegs the guage when sitting). The car has 15,600 original miles, runs great and motor has never been apart. 322 V-8, new water pump, new 160* thermostat, new belts/hoses, Radiator flushed/rodded, timeing 3 degrees before TDC(retarded for gas), new exhaust, no leaks and ran great (normal on gauge) all winter. Lazer temp sensor says 220* at top of radiator and 180* at bottom. However in 95* heat, it is peging the gauge when I slow down. Anyone have any sage bits of wisdom/ideas to pass along?? Maybe the gauge is bad?? I want to tow my 1935 Garwood speedboat with the car but am afraid to. Email me here or call me Toll Free at (888) 370-4474 during the day Eastern time.

Thanks,

Garland Gentry

BCA# 40133

[brad54]

Does your car still have the radiator shroud on it?

Also, check that the fins aren't caked with paint from when it was redone.

Make sure the thermostat is opening (throw it in a pot of hot water on the stove and see if it opens).

Check the radiator cap and make sure it is correct for your application (that will affect it).

Make sure the heater hoses aren't plugged, etc.

Is it a two row or three row radiator?

Might need an upgrade to a bigger one. (I'm having Griffin Radiators make an aluminum one for my '54, and then I'm going to paint it black and nobody will be the wiser)

Could also add a 5-blade fan to draw a little more air.

As a tip, if you're overheating in traffic, turn your heaters on--they'll act like little radiators. You'll be miserable in the car, but it'll help get you home! And you might even sweat off a few pounds!

Hope this helps,

-Brad

[Guest]

Brad,

Thanks for the reply. I've done all you suggested including special turbo cool 5 blade fan. Radiator seems fine, paint OK, shroud in place, rad cap new. Still no luck cooling her down.

Thanks,

Garland

[Pontiac59]

It's possible for the impeller on a water pump to slip on the shaft and prevent cooling even on new and particularly on rebuilt examples.

Does it actually steam and overflow out of the car? Might run a hose off the overflow to a tank or to the ground to prevent the coolant from messing up paint, etc. on this car.

I would try an independent gauge and sensor on it and see if the guage is in fact working correctly. You might also check compression and run it cold with the cap off the radiator and watch for signs of a head gasket leak (smoke rings out the radiator cap). Make sure the heat riser valve isn't stuck in the exhaust manifold, too.

had a Pontiac 301 once that would overheat every few miles if you drove slow and never did sort it out, there wasn't any obvious reason for that.

[old-tank]

Garland

A few points: The stock guages on most of these old Buicks are "pegged" at 190 and I like you get worried with looking at a high reading.

Plain water with rust inhibitor and water pump lube dissipates heat better than 50% antifreeze.

Nail heads do not like to be retarded..ignition that is...my 55's run well on mid grade unleaded with the timing set at 5-7 btdc. Check your vacuum advance! An broken one will really add to the retard.

Increase your idle speed to 800 rpm which will increase coolant and air flow. Or put in neutral and rev the engine if idling will be prolonged.

All of mine WILL run hot if stuck in traffic after high speed driving.

If you have a good radiator cap and it is not boiling over don't worry. (easy to say...)

Willie

[Guest imported_NikeAjax]

Um, I had this same problem, and couldn't figure it out until: have you looked at your freeze-plugs? A car this old should have them extracted and have new ones put in - they're really pretty pesky little things. Even a pin-hole, which a lot of times won't show anything at all, will make you want to use your car for target practice using armor piercing rounds! These kind have the nasty habit of showing up 20 or 30 miles from home, where just as things would be, you're out in BF-Egypt and all on your lonesome!

Just a thought,

Jaybird

[Guest 53and61]

Could you have rust and scale build-up in the block and heads? This would be more dependent on the engine's age than mileage. A friend's low-mileage '60 nailhead had a recalcitrant overheating problem that a mechanic finally cured by soaking with dilute hydrochloric (muriatic) acid in the cooling system followed by pressure back-flushing. I believe aluminum and pot metal are attacked by HCl, so this method may be risky -- if memory serves, the thermostat housing and parts of the water pump are pot metal. Or if you have too much time on your hands you could pull the heads and look in there.

[Guest imported_NikeAjax]

Copy that! You shouldn't have any pot-metal or aluminum to worry about if it is a stock '56 though; it should be all cast iron. What I would recommend is taking out your freeze plugs, you’ve got three on each side, and with a big wire to probe with, see if you can dig out sludge. Even after I had my engine boiled out, I found lot’s of it impacted: this s**t is very hard! A chemical pour-in type cleaner won’t get rid of this. You might want to get an air compressor and blow the stuff out between digging/probing, or a spray gun to wash the crud out with; pulling your heads will help in the clean-out too, because you get a better angle of attack, as well as making it a more thorough cleaning procedure. The worst stuff will more than likely be at the extreme corners of the water jackets, accessible only by removing the heads.

Just some ideas,

Jaybird

[brad54]

Thermostat housing will be aluminum, and anything caustic might attack the thermostat itself, too. I'm also not sure I'd want that stuff around the temp sending unit.

I've never had the problem you have, however---Rather than taking an engine block and heads to a machine shop to have them hot-tanked, I like paying a little extra and having the whole engine block and the heads chemical stripped. Find one of those places that will dip a whole body. This isn't "acid dipping" but rather a chemical dip that doesn't remove metal (as acid does) but removes everything else, including rust. When you get them back the parts look foundry-fresh.

Just two more cents' worth.

-Brad

[Guest 53and61]

Following Jaybird's idea, you could pull just one freeze plug and inspect what you can see through the hole. If it's a mess, you'll know what the trouble is. If pristine (which I very much doubt), you'll know the problem is elsewhere.

[Judd]

Garland

I had this problem with my 56 Special it was the air recirculating around the top of radiator. I used foam tubes for insulating water pipes one in front of radiator in gap to the core suport and one on bar that holds in insulation to hood it cured the problem unless I iddle for 15 minute or more.

Judd

[JohnD1956]

I had a three core radiator made last summer. At first the car was right then it started to creep upwards again. Later, for unrelated reasons, I drained the radiator and while it was dry, I noticed there was crud on top of the cores again.

I had the radiator disassembled, and all the cores cleaned, then I got a in top hose filter from TEBKS enterprises. This is a fellow in the Riviera Club from Australia. The filter is easy to install, and I left my heater disconnected so none of the coolant could possibly circulate back into the radiator.

This filter is pretty neat. It has a screw on cap and a stainless steel filter with plenty of screen holes so as to provide sufficient flow. Meanwhile I can't believe the crap it has caught.

I also agree with the other poster, who recommended pulling the freeze plugs. There are alos two pet-cocks on the block. You may be able to unscrew these without messing with the plugs first. If the hole is covered over with a layer of rust, then you really need to pull the plugs and flush the bottom of the motor out.

Good Luck