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Brought the '56 to college with me (overheating?)...


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I'm a University student (yes, I'm young). I've been waiting for the day to bring my car up with me to school and it finally came this past Sunday. I drove the Buick about 70 miles to my place, officially marking the longest trip I've taken in it. I had no idea how it would perform on the freeway and thankfully I wasn't disappointed. It was a bit hard to control at times - I'm not sure if that's due to the Remington bias plys or the steering. I rebuilt the intermediate rod and replaced the tie rod ends. I think it needs a steering box adjustment. I took it up to 80-85 just for kicks and it had more to go. It actually handled better at higher speeds. :)

The car has never really ran hot on me before. In and around town it stays at N, just above it or just below it. However, after a few miles on the highway, it started creeping toward HOT. It stopped just before the red zone and fluctuated a little depending on whether I was going uphill or down. When I got off the highway, it was having trouble cooling back down so I pulled over. It behaved the same way in 80 degree and cooler night temperatures.

  • I installed new upper and lower radiator flex hoses. I read that the lower hose can collapse at higher speeds. It does have a spring in it but the angle is kind of tight, so perhaps it's buckling. (need input)
  • I installed a new 160 degree thermostat on Saturday.
  • I flushed out the radiator and block (3 petcocks in total) with a garden hose and added new 50/50 before the winter.
  • The timing is set at 5 degrees as per the shop manual.
  • I read that if the mixture is too lean it can overheat, so I adjusted the carb and set the mixture screws a little richer.

I'm thinking of flushing out the system once more and maybe installing a molded lower hose instead of a flex.

Please let me know your thoughts.

Thanks guys.

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Almost certainly your radiator is still plugged up. You'll need to have it professionally cleaned out, which kind of stinks if you're a college student. Just flushing it with the hose will never unplug those radiator passages. (My '53 had the exact same problem when I bought it)

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Yes it is the radiator. You can turn on the heater to help and cool it down as this sometimes works a little too as you are going down the road.

But to correct the problem, take the radiator out, takes about 1/2 hour with draining and all. Bring it to a radiator shop and have them flow test it. That way you can get an evaluation as to the amount of blockage. If you can't spring for that then reverse flush it out yourself and flush the block out too after removing the thermostat. To really do it right on the cheap get a water manifold gasket, a thermostat gasket and a water pump gasket and remove all three. That way you will have access to the water manifold orifices into each head bank as these openings can clog up as well and it's easy to get to them at this point. Then clean out the areas where the water pump sits up against the timing chain cover as this area tends to collect crap. Disconnect the two heater hoses and plug with bolts. Get under the car and remove the two block drain cogs on each side of the lower block. Then reverse flush the entire engine block out separate from the radiator as this has already been removed. If you have access to an air compressor/hose go to the hardware store and rig up a combination coupler on the cheap to have the water and air funneled into a common coupling so you can add air and water at the same time. Set it up so you can turn the air on and off at will while the water is still running. Keep the air pressure low as a little goes a long way. This helps to dislodge the stubborn crap. If you have access to hot water from a tap then that is even better. By having the water manifold and water pump removed along with the lower block cocks removed you will have flow access to the entire block cooling system. Then clean out the heater core with a reverse flush but without the air and be careful to only use very low water pressure. The heater core can only take around 18-psi tops, so gently flow it out by turning the faucet down to a low flow.

When you have more time than money this is usually a sure cure.

Hope this helps.

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It sounds like a partially blocked radiator to me. If the car sat and sat and sat or was very rarely driven, or owned by a little old lady who never flushed or changed the anti-freeze every 2 or 3 years like you are supposed to do, there is probably crud in the radiator. One more test is to run car until thermostat opens up (leave radiator cap loose), and when the thermostat is open, take off the cap, shine a flashlight into the radiator tank, and verify that the coolant is actively flowing in the radiator. It should look like a little river in there.

I admire you for taking the car to college. When I was in college in the late 1970s, I drove my 1958 Buick Limited 4-dr. hardtop from Texas (home) to Georgia Tech in Atlanta, about 800 to 900 miles each way. It was my only transportation, and I could fit almost everything I owned at the time into the trunk and back seat of that car.

Pete Phillips, BCA #7338

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The radiator might look good as you look down through the filler cap hole, but that's just the condition at the place you're looking. The bottom is where everything settles to and that's where the restrictions will be--especially on a later model cross-flow radiator. An infrared thermometer can tell the tale pretty easily.

I don't recall if it was mentioned, but to do it right, you'll need to remove the core plugs from the side of the block, too. Especially the rear ones. As many engines normally sit in the vehicle with the rear of the engine lower than the front, guess where things settle out to--the rear of the block's water jacket.

Getting the radiator done first would be a good move. That will probably get a lot of the problem remedied itself. Then, on a long weekend and maybe even with the car on a lift or in a rented service bay, you can do the more involved partial disassembly (as mentioned above) and do the "wet and messy" stuff to finish the clean-out. At that time, too, you can do a reverse flush of the radiator for good measure.

One of the guys mentioned using a coolant "filter", made of nylon panty hose inserted (somehow or another, probably loosely stretched over the radiator neck) where the upper hose attached to the radiator. There are genuine cooling system filters in the heavy duty truck part of the automotive world, but this "shadetree method" might work too.

Factory molded hoses are always preferrable to the universal flex radiator hoses. To me, each of those flexible bends will induce turbulance and air bubbles into the coolant mixture, even under pressure. Or flow restrictions unless there is a total absence of laminar flow.

The springs in the lower hoses used to be pretty much standard for all vehicles, but for some reason, they're not being used in more modern vehicles. Might it be that once the cooling system pressures-up, the chance of collapsing greatly diminishes? But, for good measure, use one where one used to be.

Lack of advance in the distributor (usually from a non-functional vacuum advance) will usually result in increased fuel consumption rather than a real contributor to overheating during a cruise situation.

When they talk about "lean mixtures", that's in the main system of the carb. All the idle mixture screws control is the mixture for base idle and a little above that, not much above 1300rpm or so, where the "main system" takes over. Usually not a major contributor, either, but like the retarded ignition timing, might help an overheat situation along when combined with other issues.

Once you get it all done, the mess and such will be worth it . . . or should be.

Good luck! Enjoy!

NTX5467

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There are a couple shops around me that say they will clean it out (pressure blast/boil out... not sure which) in a half hours time for around $50 if I bring it in. Is it wise to get this done before I remove the freeze plugs and manually pick out any sludge? Should I try flushing/reverse flushing the system before I get the radiator done? I just don't want it to get clogged up again.

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if you have a tight bend with the lower flexhose, it must be too long for what you need, with a molded lower hose, you must have a good spring inside. even when the system was warm and pressurized, i've seen the lower molded hose minus the spring completely collapse under moderate accelleration. you can check your hose, by having someone raise the rpms quickly while you watch the lower hose. charles coker, 1953 pontiac tech advisor.

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I'd say "Get the radiator done first", at least then you'll have that done and the vehicle will be more useable afterward, hopefully. Only expense might be more antifreeze/coolant "twice".

Even if you might get some "stuff" in it, it should come out reasonably easy as it hasn't been in there all that long--hopefully.

Be sure to make sure what you're getting for that $50.00. PLUS that they pressure check it for leaks afterward. Be prepared, though, as you might end up needing to have it re-cored anyway, after the cleaning is done. Sometimes, dislodging deposits will take some of the base metal with them, which can make the tubes too thin to be reliable. Not unlike using rubbing compound on paint. It can make it shiney and remove scratches, but it also makes the resultant finish's outer surface much closer to the base primer.

Just be sure what you're getting for the $50.00 and ask them what the worst case scenario might be BEFORE you get it done (with appropriate pricing).

Just some thoughts,

NTX5467

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1956 Century: In reply No.4, I tried to detail out a recipe for you to follow as well as others. There is no short, quick fix to overheating problems with these cars and the guys you may want to take you car to are certainly not going to bend over that extra foot to really do it right for you and you can't expect them too certainly not for $ 50 bucks. So, you have to go point by point and follow the advice you have received. Do as much of the "Block System" cleaning yourself. Pay yourself to do it. Then take that radiator out and get it flow tested. It is crap then use it for target practice and get a new radiator. But the block and system has to be good and cleaned as detailed in reply no. 4. Then when everything is virgin and right, then install the new or rebuilt and certified radiator.

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All here, have; given excellent advice.

I would, like to add something regarding; what has been mentioned about, lean fuel.

Ntx5467 made a good point about the fuel mixture.

Lean fuel can cause overheating. It is usually from a clogged line or, filter. And, not the mixture setting in the carb. Mine overheated once due to; lean fuel. A clogged fuel filter was the culprit. However, the overheating was only in the heads. The coolant in the radiator was normal temperature.

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All here, have; given excellent advice.

I would, like to add something regarding; what has been mentioned about, lean fuel.

Ntx5467 made a good point about the fuel mixture.

Lean fuel can cause overheating. It is usually from a clogged line or, filter. And, not the mixture setting in the carb. Mine overheated once due to; lean fuel. A clogged fuel filter was the culprit. However, the overheating was only in the heads. The coolant in the radiator was normal temperature.

I'm experiencing these same issues in my '58. Checking the temp across the radiator (and at the inlet and outlet points), my rad seems to be doing it's job, however the car overheats ONLY at highway speeds.

I have been told to check 3 things

-fuel pressure (at the fuel pump inlet)

-timing

-oil pump screen.

I haven't gotten around to it yet. :( I need someone else to double check the timing for me as I THINK I have it set right.

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I'm experiencing these same issues in my '58. Checking the temp across the radiator (and at the inlet and outlet points), my rad seems to be doing it's job, however the car overheats ONLY at highway speeds.

I have been told to check 3 things

-fuel pressure (at the fuel pump inlet)

-timing

-oil pump screen.

Any one or a combination of these could cause lean mixture. And, lead to overheating. The fuel actually provides a cooling effect int he combustion chamber and heads.

I haven't gotten around to it yet. :( I need someone else to double check the timing for me as I THINK I have it set right.

I've replaced the points, with; a solid state distributor. That, eliminates setting the points. But, setting the timing, is; elusive to me as well. I'm lucky to have a very accommodating (to the hobbyist) professional mechanic.

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Fuel pressure (at the pump inlet) would actually be "vacuum" rather than pressure, I suspect. Not really sure how that would relate to lean mixture at cruising speed (where the carb's main system would be in operation). What might be happening is that the fuel line (which I understand is a rubber hose all the way to the tank, no metal tubing) could be having a problem somewhere--internally. That could result in a higher vacuum reading than if the line was completely clear and open.

How's the fuel economy been since this overheat-at-cruise started? Reason I ask that is that if the fuel economy has deteriorated, then it could be a sign that the distributor's vacuum advance is not functioning, leaving the only timing advance the engine gets being what's in the weights and springs. If the vacuum advance was working and the engine clattered from too much timing, at cruise or slight accelerations from that speed, then that would mean the base timing was "too much".

That's the first time I've heard "Check the oil pickup screen" as relating to highway speed overheat issues. It's possible, I suspect, but if the overheat went away or decreased with fresh oil in the pan, with fresh "lubricity", that might be a possibility. At the same time, though, if the oil films were so thin as to cause extra heat to be built by the friction surfaces in the main and rod bearings, that engine's not going to be around very much longer.

Under what conditions did you do the infrared thermometer check on the radiator? Just curious if it was with the car sitting still and the engine at idle? If the car was sitting still and the fast idle screw was on the highest step on the fast idle cam? If the car had been driven on the highway until the overheat situation appeared, then the car was pulled off of the roadway and the radiator temps checked then?

Now, here are TWO things . . .

1) In the head gasket, there are "holes" which fit over the water circulation holes on the block's deck surface(s). These "holes" are generally smaller than the passages in the block, so they act as restrictions to coolant flow. If, with age, these holes have enlarged (whether in a steel shim, copper, or composit material gasket), then water can flow through the system too quickly (yes, too quickly), which can increase turbulance in the coolant's flow (air bubbles) and therefore decrease the amount of the surface area of the block's coolant passages which actually touch the water to remove the heat. Until the relative flow rate to rpms (and road speed) increase to the point where the water is going through the system too fast, things can seem to be fine.

2) From what I've seen and experienced, your issues with the '58 would usually be more "mechanical" rather than solely related to fuel supply issues or ignition timing, although these things can be contributors or contributors which can point to the fact that another operating system is becoming more marginal in ITS operation. One other "mechanical" issue, in this case, might be the thermostat. This is another area where flow rate is controlled. In the case of circle track racers (and some others), they use washers instead of a thermostat in the cooling system . . . BUT washers with a particular hole size in the middle, which is the flow regulation function rather than heat regulation.

When vehicles are new, there can be many part numbers for thermostats and fan clutches, especially fan clutches. As time and age of the vehicles progress, many of these applicatioins (especially fan clutches) are combined into fewer part numbers. Many of these "purpose built" items become "will work" items, typically. Also, I've observed that as time has further progressed, the number of actual manufacturers of replacement parts has dwindled, such that fewer suppliers are now selling more items to other re-sellers than ever before. The older comment "They're all the same" is generally more true now than when it was first used decades ago! Be that as it may. Therefore, I'm wondering just how far off of the original factory specs for coolant flow the now-available thermostats might be?

Here's a third consideration, too, from my own experiences.

When I ordered my '77 Camaro, it came in with a 305 2bbl rather than the ordered 350 4bbl. 350 engines were on "STOP" at the plant when my order came through, so a 305 (and related things) were substituted. One thing it did have was a factory flex fan. I thought this was neat and liked the fact that it had it. I'd read about flex fans when Ford started using them on some 1964 cars and liked the concept. The fan on my Camaro was quiet, too, at higher rpm compared to a normal fixed-blade fan.

As the car aged, I upgraded the radiator to a 3 core Modine. As things progressed into more years, I started to get a "creeping heat" situation at highway speeds (which meant an rpm of about 2000rpm at 60mph). I checked everything and it was all in good condition. I thought that with age, the flex fan might be flattening out too much, so I changed it for a new one--no significant change. As it was the factory configuration, it was where it needed to be in relation to the fan shroud.

What I suspected was that the flattened-out fan, at speed, was blocking airflow throught he radiator. I did some research in the parts books to find the best clutch fan and fan combination for that car. I still wanted good cooling at town speeds, but for it to freewheel at higher rpms (as it was the thermostatic style of fan clutch). So I got it all figured out and installed. End of heat problem at that time. The flex fan might have done a great job at lower speed when it was at "full pitch", but as it flattened out with increasing rpm levels, it apparently was blocking air flow through the radiator in that situation. The clutch fan would freewheel and not restrict anything. That was the GM factory flex fan.

In the middle 1970s, I was shorter on funds and was tired of fan clutches having a certain life span on the car I was driving at the time. I was thinking about a stainless steel Flex-A-Lite fan, rather than the less expensive fiberglass fans. So, I went to Speed Equipment World in Fort Worth and ordered up the necessary spacers and such, plus the stainless steel flex fan. When it came in, it was a marvelous shiney fan! I got it installed and had mixed emotions about it.

This was in the summer time, so temps were higher. It was noisy! With 8.55x14 tires and a 2.76 rear axle ratio (calm down, Pete, it's a different but similar car), by the time I got to 70mph, it sounded like it was getting ready to take off. Not exactly what I wanted, but I ran it in hopes that it might flex a little more and quieten down some--not. The good part was . . . in 100 degree ambient temps, I could drive it for 1 hour on the freeway with the a/c chunking ice cubes, get home, and immediately raise the hood and remove the air cleaner WITHOUT any theatrics due to "hot parts". To me, THAT was impressive! But, with that benefit, the noise was too much.

What I then did was to "shadetree it". One of the techs at the Chrysler dealership had done this on his car, for the same reason that I was looking for alternatives. It was "low cost" and took just a few minutes to do. By the way, I got to where I could change fan clutches on that car in less than "factory time". On the front of the thermostatic fan cluthes, there are two bulges as fluid reservoirs. When the clutches don't work very well, it's because the silicone fluid has leaked out, so putting some dimples in the fluid reservoirs effectively increases the fluid pressure and delays the "freewheel" function until a higher rpm. What he did, though, was to take a Phillips head screwdriver and put a "stake" in each side, effectively clamping the two halves of the clutch together for a "solid drive". I liked my approach, better, though as the clutch function still worked, just at a higher rpm. And that's where it stayed until I could afford a correct new fan clutch for the car a few years later.

Just some thoughts, respectfully,

NTX5467

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If the car has power brakes - check that you do not have a vacuum leak through a cracked hose or diaphragm in the booster bad. Same with the wipers and any vacuum hoses related to these two components - especially the vacuum hoses under the dash to the wiper switch. That could lean things out - carb bolts tight - carb gaskets good?

Ron

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Interesting...didn't even consider that!

All added to the list.

When the gates of hell decide to open and drop the temp below 90, I'll start looking at it again!

Gaskets are good. I was getting a little steam out from under the carb until I replaced the gaskets and tightened the bolts.

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Steam?????????

Or gasoline vapor?????????

Loosing water????????????????

Ron

I thought it was steam....tiny bubbles. I guess I need to check for head gasket leaks too, although the oil shows no water.

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You lost me there...It's a freshly rebuilt carb from a super nice core.

Well; I'm no mechanic.

But;

I'm thinking about the carb heat system under the carb. Inside, the intake manifold; exhaust gas is passed through a channel to provide necessary heat to the carb. The carb sits on a spacer/heat shield. There, may be a leak in; this heating system............

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Interesting...didn't even consider that!

All added to the list.

When the gates of hell decide to open and drop the temp below 90, I'll start looking at it again!

Gaskets are good. I was getting a little steam out from under the carb until I replaced the gaskets and tightened the bolts.

Absolutely, the radiator needs; attention.

This, is the symptom that, has me thinking about; the carb heat..........

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So, even if infrared shows that there is a 40+ degree drop in temperature of coolant as it makes it's way through the radiator, your point is that the FLOW may not be sufficient?

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The trick is to measure from side to side, in the middle. A comparatively lower temp in one spot or another would indicate a clogged tube.

Comparing temps from top to bottom, perhaps at the tanks, would indicate how well the radiator is cooling over all. Top would be hotter, bottom cooler, so long as some of the tubes are flowing.

A more modern cross-flow design would measure the opposite, mutatis mutandis as they say.

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I don't know about the area where you live ( each , respectively) but where I am we have a lot of cotton wood trees which give off a puffy cottony white pollen each spring. While doing the A/C on my 69 I noticed the front of the radiator was coated with the stuff. So I looked and found it was coating my 3 core on the 56 also. I cleaned it with an old toothbrush and a flush of the garden hose ( not a jet stream, just a flush) to avoid bending the core fins. Seems to have made a big difference in the GS but I haven't tersted the 56 on the road yet.

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  • 2 weeks later...

Just a small update:

I had a chance to reverse flush the radiator at home with a hose. Nothing but clear water came out. I have a feeling this is not something I will be able to tackle at home. I will follow the advice given by buick man, NTX5467 and others and take it to a radiator shop and have them flow test it while I clean out the block as best I can at home. I'm not sure if I'll go as far as removing the freeze plugs, but we'll see.

Thanks

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Flow testing is a waste of time and money. Cap off the heater core - use some oxalic acid with the thermostat removed. Drive a day or two and flush (you MUST pull the block drain plugs). Put in a good thermostat in and see if the problem is still there. If still there - then the radiator is plugged and needs to be rodded or recored or you have either (or both) a bad head gasket or a cracked head or block. There is a slim chance that the water pump impeller is defective.

Have rou actually verified with a new temperature gage that is accurate that you are indeed over heating???????? Do not depend upon a 50 plus year old gage to be accurate - it was only ball park when new.

Ron

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Excellent point, Ron

The old car guy's best friend is an "InfraRed" or "Laser" thermometer.

Instant, accurate readings can be taken anywhere in the system. THermostat

housing, radiator, block, heads, etc.

Even my "new" AutoMeter gauges (not in a Buick!) are now known to be at least 10-20 degrees too hot in their readings. Used it regularly when I ran my front engine alcohol dragster as a cheap alternative to expensive exhaust gas temperature probes in

every exhaust port. Now it comes with me on any old car outing....

I just don't trust old or new gauges all that much.

mike

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I like my "laser" probe as well but a know good gage is something that more people can easily understand. It is relatively simple for people to install and to understand and trust.

The real truth of the matter is that with a know good radiator cap and there is no boil over then the engine is likely fine. But as the OE gage gets old, the accuracy is all over the place. Especially if it is electrically driven - any corrosion anyplace in the circuit from the battery - generator - regulator - chassis ground can provide a false reading temperature gage due to voltage fluctuations.

So the sender needs to be checked (removed and threads cleaned) and the gage wires checked. By checked, meaning the connections removed and cleaned and reattached, But you still need a second know good gage to verify the OE setup.

Ron

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I got lucky, there's a digital laser temperature reader on sale at a store near me this week. I'll pick that up and see what the engine actually reads. Where should I be pointing, thermostat housing and up/down the radiator? Is sub-200 degrees considered normal?

Thanks

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Assuming that both heads are the same, there should be a plugged outlet on the "other" head from the one where the temperature sender is located. Buy a mechanical temperature gauge and hook that up to the spare outlet. At the same time, replace the sender unit. My money is however on the radiator, but the above will give you greater piece of mind once the problem is resolved.

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