New to SBC's; idiot question

[BeratE]

The 40 I have been tinkering on over the winter finally got a little exercise last night. When I pulled back into the stable I noticed that the heater hoses were very warm, but the two main radiator hoses were ambient temperature. I gave the upper hose a good squeeze and did not feel any fluid move, in fact the hose was completely empty. I gave the lower hose a good squeeze and felt something weird inside. Today I drained the coolant and checked inside the hose only to find a long spring that is apparently helping to prevent hose collapse. One mystery solved. Now the other mystery is that it appeared as though there was no coolant flowing through the upper hose, and seemingly no coolant flow at all. If I were to take off the belt and manually spin the fan, should I be able to pump fluid out the top hose? If a water pump fails, does it completely stop pumping?
Sorry, but I am learning as I go. Thanks for the help

 

[Maros N Bagos]

Sounds like it was low on coolant

 

[ranger]

Usually a tell tale sign of the pump going out is either bearing noise, play in the shaft, or antifreeze coming out of the weep hole.
Check your thermostat first.

 

[BeratE]

Thanks for the responses. Does the thermostat open a valve to allow water flow because my fan is not the clutch variety. Shouldn't water be pumping whenever the crank and therefore the fan attached to the pump is turning?
Maybe it does work fine, but to prove this to myself though, will manually spinning the fan manage to pump water?

 

[60fj25]

Depends upon how long you drove the vehicle, how cold it was outside and if you had the heater on (it's a small radiator). If you didn't drive it very long it is possible that the engine never reached the temperature needed to open the thermostat to allow water to flow through the radiator.

 

[dgangle]

replace the thermostat/gasket and top off the fluid.

Methinks you would have to really be spinning that sucker to see it actually flow fluid. Like said b4, if it ain't noisy or leaking, chances are it's doing the job.

 

[msapers]

On a SBC, you can remove the thermostat entirely. Then refill the coolant and start the engine with the radiator cap off. Look into the radiator as you rev the engine. You should see coolant flowing. Personally, I run mine without a thermostat and it cools better while still getting hot enough to make the heater work properly. Some will say that removing the thermostat will reduce the efficency of the cooling system, but in all my years with SBC's I have always seen a great improvement in cooling.

 

[pb4ugo]

Basically, w/the Tstat closed(cold) the water will bypass the upper hose and rad and circulate the water thru the engine and heater.

 

[dgangle]

Generally speaking, removing a T-stat is a bad idea. That's like turning your furnace up as high as it will go, opening all the windows as far as they will go and then complaining because it's either too hot or too cold in your house.

Can I remove my thermostat in my car? - Yahoo! Answers

If one needs more flow (which is usually due to some other problem such as an undersized radiator) then this can be accomplished with a high volume water pump and thermostat.

 

[thecrazygreek]

Generally speaking, removing a T-stat is a bad idea. That's like turning your furnace up as high as it will go, opening all the windows as far as they will go and then complaining because it's either too hot or too cold in your house.

Can I remove my thermostat in my car? - Yahoo! Answers

If one needs more flow (which is usually due to some other problem such as an undersized radiator) then this can be accomplished with a high volume water pump and thermostat.

true, but TS's can be a real PITA... You can buy them new and they can fail. Getting rid a a ts is not going to hurt your engine. Just take longer to warm up. And you wont have to worry about it failing while on your 300 mile trip...

but I could be wrong...

 

[dgangle]

Edumacate me here. How exactly does a thermostat fail? Been driving for over 3 decades and working on them for a couple more and have never had one 'fail'.

 

[thecrazygreek]

Fail as in "gets stuck" in the closed position. Consider yourself lucky I guess...

The spring will activate based on the temp. Sometimes the spring doesnt "activate" leaving the valve in the closed position. I have actually purchased two dead thermostats in a row. The third worked fine.

I assume the cheaper the thermostat, the more likely to fail it will be. (in yoda speak)

 

[Brian in Oregon]

One problem with removing a thermostat is that with a very efficient cooling system it can actually cause overheating.

I've seen this before with big four core radiators and high volume water pumps, with the thermostat removed. The coolant flow rate is so high that there is insufficient time for heat exchanging in the radiator. The water cools a bit, but not as much compared to a slower flow rate. It can really be frustrating because the person fighting ever increasing temps does not realize the cycle he has set up. So the next logical thing is an even BIGGER radiator, which makes it worse.

The trick to removing a thermostat - on race motors - is to replace it with a restrictor plate. This is simply a circle of brass or aluminum with a hole cut in it. Like a doughnut, but flat. This reduces to the flow rate so the coolant has time for proper heat exchanging in the radiator. This is not recommended for street engines.

And even if there is no overheating, there can be excess wear from too much cooling.

Engines that take an excessive amount of time to come up to temp can cause excessive wear due to low tolerances. Some chokes will remain on longer, which can result in excessive fuel usage plus washing down cylinder walls with gasoline, reducing lubrication. If the choke comes off too soon, drivability is reduced. The engine stumbles and is "cold blooded".

Low operating temps can result in increased wear. This is because tolerances are machined for a particular temperature range. If you take an engine that was designed for 210 to 220 degrees operating range, and run it with a 160 degree thermostat, the tolerances are less because there is less expansion of the metal. The result is more wear. Charts showing this have been made for decades, and ignored for decades. Race engines have increased tolerances machined in because they are designed to run with less expansion, especially drag engines.

This chart shows the increased wear rate when an engine with normal production tolerances is run excessively cool.

From: HOTRODSRJs COOLING TIPS Operating temperature vs power and longevity!

 

[dgangle]

if water cooled engines didn't benefit from a T-stat then designers wouldn't include them. Does one shadetree mechanic think they are smarter than the engineers at GM, Ford, Chrysler, Honda, Toyota, Hundai, MB, Audi, Honda, Yamaha, Suzuki, KTM, BMW, Kia, .....................................?????

 

[BeratE]

Thanks for the varied responses guys. It is now very clear to me that it is not surprising that coolant had not been pumped to the upper radiator hose, since most likely the motor had not gotten up to temperature. Without the thermostat activating and opening a valve, I should not expect to be able to spin the fan by hand and have any fluid pump out the upper hose. Second mystery solved.
Next question: is there any way to determine what temperature thermostat I have, since I cannot ask the guy who installed it in the first place?

 

[TLCHopII]

If you pull it out there will usually be manufacturer's stamp on the cage which will indicate operating temp. range. re-installation will require anew gasket.

I would just replace it. they are cheap. Why not eliminate a possible bad t-stat from the equation? Buy a "Stant" brand or similar thermostat that is designed to fail in the "open" position.

That said: Please post up a pic of set up. The frame should be a side view of the engine compartment including the front of the engine, radiator hoses and radiator.
I ask for this as it should be possible to "burp" the air out of the return hose while filling the radiator. This is made possible by the tendency for TLC radiator installs to position the return hose below the radiator fill and above the SBC block. Also as you stated this is somewhat new to you and there could be another issue that would be caught by a more seasoned eye.

FYI: as for the heater hoses being hot. does your cruiser have a heater, water flow, control valve installed in it. It is not uncommon for the stock valve to be removed during the conversion and not be replaced. therefor the hot coolant circulates throught the heater core whenever the engine is running.

 

[bsmith123]

temp

put it in a pan of water on the stove if you have a thermometer that goes high enough---bingo

At least in my experience they rarely go bad and are worth having for one reason you'll have heat sooner!

Also the engine will run better cold

you could just test it by putting it in a pan of boiling water and if it opens you'll be fine


if your water pump was not pumping or your thermostat was stuck closed your temp gage/radiator would soon let you know

If it is stuck open you get the same probs as removing

 

[rockcrawler]

Engines that take an excessive amount of time to come up to temp can cause excessive wear due to low tolerances.

Certainly the biggest concern about running engines without a thermostat is increased engine wear. All the tolerances built into an engine (including bearings) have been calculated with the materials at normal engine running temperature. When an engine is running below this temp parts have a "looser" fit. With a crank bearing for instance, this will cause uneven wear as the bearing receives most of the force on the torque side. Conversely, overheating causes metals to expand and this increases friction/wear.

One of my friends took his car to a well known chain of auto repairers over here as his engine was overheating. A few days later I asked him how his car was and he told me they had fixed the problem by removing his thermostat! Needless to say I was speechless. I got him to buy a thermostat and fitted it. A bit of fiddling with his Holley and his overheating problem was cured - the engine had been running lean. After this I got him to drive back to the workshop and gave that "mechanic" a piece of my mind, left him as red-faced as he should have been.

My advice, if you love your engine, never run it without a thermostat unless you're stuck in the middle of nowhere without a spare, and then only long enough to get to the nearest garage.

 

[theoii]

put it in a pan of water on the stove if you have a thermometer that goes high enough---bingo

At least in my experience they rarely go bad and are worth having for one reason you'll have heat sooner!

Also the engine will run better cold

you could just test it by putting it in a pan of boiling water and if it opens you'll be fine


if your water pump was not pumping or your thermostat was stuck closed your temp gage/radiator would soon let you know

If it is stuck open you get the same probs as removing

The time it takes to test a T-stat you can just replace it with a new good quality T-stat. As for temp most older (pre smog) SBC were 180 degree. And if you go with newer computer control SBC the operating temperature is more critical to optimum output.