Why is my water pump so hot?????

[slocrow]

I'm still fooling with the hot engine while standing deal so in an effort to isolate the problem and gather more info, I bought a point and click infrared temp reader at Harbor Freight. They were on sale for $30 and I told the wife that we would use it in the kitchen more often for measuring the likes of frying oil, frying pan surface temp, meat exterior, etc. She bought the story and I bought the gauge.
Anyway, while my on board temp gauge was reading 190 from the sender at a point in the manifold next to the thermostat, I shot other locations on the engine and am confused as to the reason the water pump was hotter then I would think it should be.
Standing still with the 2350rpm Spal on, the water exiting the Griffin read 120. As water climbed the lower hose it pretty much stayed 120ish until it got to the pump inlet where it jumped to 145/150. No matter where I shot the pump it was 145/155. The thermostat housing and upper hose were 187 and the radiator top was 185ish.
I do have that bi-pass hose from intake to pump top and that was 185ish too, I think.
What I don't understand is if the water coming out of the radiator is 120, why is the pump so hot as it's passing this supposed 120 water through it and into the block? Or, is something else going on that I'm not aware of and causing the heat!
Thanks for any observations, Frank

[wayne petty]

coolant circulation theory...


with a thermostat in place... and a by pass also

the coolant is pulled from the lower hose by the pump....

the pump splits the flow and pushes it into the front of the block...

it goes around the cylinders till it get toward the back of the block... then up through the openings at the back of the head gaskets,

forward through the heads to the intake water crossover or where ever the thermostat is located...

the thermostat blocks the circulation through the radiator until the flow of coolant across the back of the stat causes it to open slightly..

when the stat does slightly open...   the cool water in exchanged with the hot.. this cool water causes the stat to close letting the water circulate and pick up heat...

this is where the bypass circuit comes into play.      it is smaller than the rest of the coolant passages.. this restricts the flow... this restriction increases pressure built up by the pump in the block.. 1 pound of pressure increases the boiling point by 3 degrees F.   this is over the pressure held in by the cap...

the bypass allows water to circulate through the block. up the back and through the heads and across the back of the stat....   just think... the stat maybe over a foot from where the heat is created...

the pressure differntial created by the thermostat being closed or partially closed also allows the coolant to flow through the heater core and hoses....  the long way through...

there is on many motors... a small built in bypass to keep the pump primed...   think of the hole below the mounting bolts on a small block chevy water pump...


so.... now that that is out of the way...


you ask why the water pump is hot... but not the lower hose/???

probably do to the bypass circuit..

i would also if you can get at it... move the temp gun across and around the cooling fins of the radiator... see if there are any cool spots... or cold tubes....  that would indicate a blockage...  or restriction...

on cars with aluminum parts... when the antifreeze does not get changed...   it turns to acid..   eats away at the soft aluminum.. and electroplates it in the heater core and radiator tubes...... it deposits aluminum oxide..  a great insulator..   not good for a cooling system...



wayne...

[slocrow]

Wayne;Thanks for the overview. If I understand correctly, you're stating that the bi-pass circuit is the culprit of the hot water pump. You're stating that before the thermostat opens completely (if it ever does) it is in a state of orifice size adjustment, being influenced by the temperature of the  coolant up against it or passing. If it's closed enough then some of this super heated water is forced by pressure to leave the block via the bi-pass and directly mixing 185' water with 120' causing a 145' mix and the pump temp.
I'm sure I'm missing something though! Let me question the theory you've presented in an effort to better understand.

"the coolant is pulled from the lower hose by the pump...."
Maybe semantics but I always thought the water was pushed into the pump via the radiator like a water tower.

"the pump splits the flow and pushes it into the front of the block..."
It's a  BB Chevy and yes I agree that the impeller forces it into the block via those 5/8" holes between the mounting points. It then proceeds throughout the engine as you described until it reaches the closed thermostat. At this point the thermostat adjusts it's opening as needed based upon water temp.

"this cool water causes the stat to close letting the water circulate and pick up heat..."
Rather then just sitting and absorbing heat, you're implying that the block's contained coolant is circulating via the bi-pass circuit. In via the normal holes and returning via the bi-pass hose in this restricted circuit.

"this restriction increases pressure built up by the pump in the block.. 1 pound of pressure increases the boiling point by 3 degrees F. this is over the pressure held in by the cap... "
This part of your explanation has me a little bewildered. I thought that as the coolant heated, it expanded putting pressure on the whole system (via the lower hose with a closed thermostat) which in this case is being influenced directly by the bi-pass circuit rather then because of pump pressure. Again, this pump pressure thing is new to my thinking and I may need a further & more simplistic explanation.

"you ask why the water pump is hot... but not the lower hose/???
probably do to the bypass circuit.."
OK, so if the thermostat is closed I can see that the bi-pass circuit is dumping 187' coolant directly into the water pump, mixing it with 120' water seeping into the mix from the lower hose and maintaining a 145' average that it's putting back into the closed block circuit.  
If on the other hand the thermostat (180') is open because the coolant is 180'+ then the system should be circulating wide open and although a minor amount may be entering through the bi-pass hose the majority coolant should be passing via it's expected routing and after a trip through the Griffin should be entering the pump at 120' and the pump should be noticeable cooler then the 145' I questioned.
At least that's my convoluted thought process, which may need correcting.

I was looking for a suggestion that maybe I had a bad water pump though I believe they either work or leak. So now I'm thinking that based upon your info concerning the bi-pass circuit I may in fact have a problem thermostat. This could cause the cooling system to be somewhat restricted and could lead to an ever increasing temperature climb while standing and idling but I presume allow enough flow of cooled water at speed to avoid an overheating incident.
What do you think? Is it thermostat in a boiling pot with a candy thermometer time?
Thanks again, Frank

[enjenjo]

Typicallyheating at idle is a timing issue, either cam or ignition.

[slocrow]

Typicallyheating at idle is a timing issue, either cam or ignition.

Yes, I know what you're saying. I still have to put in that vacuum distributer and need to move the initial timing up to maybe 14 from 10 but I thought the high temp pump may be stating another problem.
Easier to change out the thermostat then what it's going to take to install the new dizzy...............Thanks, Frank

[Crosley.In.AZ]

I am amazed you had to use  a   story on the wife to buy a 30 dollar tool.

[slocrow]

I am amazed you had to use  a   story on the wife to buy a 30 dollar tool.

All right, ya got me! I was just trying to add drama to my story with a feeble attempt at humor...................

[wayne petty]

one of the several things i missed......    

at the temps you listed... your engine is not overheating...


if your engine temps get up beyond 235 to 245 then i would start to worry..



as for the pressure in the block caused by the thermostat blocking the water flow from the pump...

that is a good thing...     under heavy loads parts of the combustion chambers, valve seat areas, exhaust ports can get really hot... but are cooled by coolant ...    the localized hot spots without this extra pressure in the cooling system will boil....  cause steam bubbles to form...  these bubbles if they were not restrained by the excess pressure in the block might displace the coolant pushing it out into other portions of the cooling system..    big buick V8's were good at this when the cooling system was marginal.. it would cause hammering noises as the coolant surges in and out of the block....


there is another point i need to raise...

thermostats....    they have a wax pellet in the brass end .... when this wax is heated it expands... this pushes the pin out and forces open the disc to let coolant flow through...   when engines are overheated... the wax expands till it forces past the seals and escapes into the cooling system...   this does not leave enough wax to push the pin out against the return spring...  the stat then does not work any more...

some smart guy invented and got into production the fail safe thermostat...  it has a latch...  if the thermostat is exposed to excess temps... it pushes the valve out till the latches catch it...  so it stays open...  this does save your motor...  and is a great idea...


now ... for thermostat replacement discs...   like the kind they use in circle track racing..     there is a reason and it is what was stated above...   it also reduces the speed of the coolant through the radiator...    if you take a thermostat out of the motor and run it without...  the coolant can circulate so fast that the pressure in the top tank can expand it and break the solder bonds that hold it in place...   (this is do to the pump being able to pump more coolant than the radiator can pass through its small tubes)

next time you have the thermostat out... and the motor has only clean water in it...   put the housing back on... pull the other end of the upper hose off...  put the garden hose in the filler neck...     let the engine idle till it fill up....    then aim the upper hose out away from the car...  rev the motor for a second...  it will throw the water 15 to 20 feet.. until it pumps the block dry.. let the engine idle until it fills again...  then rev it again...
i have always wanted to hook the lower hose to a large source of water... and have some fun...    

wayne

[zzford]

I am amazed you had to use  a   story on the wife to buy a 30 dollar tool.

All right, ya got me! I was just trying to add drama to my story with a feeble attempt at humor...................

You need to stand up to your wife, be a man!!! Do like I do, sneak it in and hide your purchase, never letting her know!

[Danimal]

I am amazed you had to use  a   story on the wife to buy a 30 dollar tool.

All right, ya got me! I was just trying to add drama to my story with a feeble attempt at humor...................

You need to stand up to your wife, be a man!!! Do like I do, sneak it in and hide your purchase, never letting her know!

You guys are sad. Can't any of you just do it right Beg off $5 a day for lunch and starve until you've got enough money to buy what you need. Then make sure you hide it somewhere she'll never look, like your sock drawer. Make sure you keep it dirty so if you ever get caught using it, you can say you've had it a long time!

Other than that, I think this is a great topic since I'm having overheating issues with my '46 Chevy 216.

[wayne petty]

what.. more hot issues....


ok... lets here what the 216 is doing.?

i am trying to remember of they have a cooling tube similar to the flat head dodge 6's        i do know that when the dodge motors get corrosion on the tear drop shaped tube that fits into the water jacket behind the water pump.. the exhaust valve seats and block will crack...

the dodge tube directs even flows of water upward toward the exhaust valve seats...  they rot off in the back of the block... and are terrible to get out without the slide hammer tool with the tapered piece and the little blocks on top to fit into the openings to extract it...

they are probably called water distribution tubes...  i just cannot remember if the 216 used them......  

by the way.... that six... and the toyota land cruiser F motor are almost identical...  one is metric .. on is not... but the toyota has full pressure lubing... where the 216 cannot ..  as the crank cannot be drilled..  as far as i know...

[Danimal]

216 was allegedly gone through, at least gasketized in about 98 or 99 but sat in a garage for the last 8 years only run occasionally. I have it running now.

After driving it up and down the street about 3 miles, it puked. I refilled it, let it run another 10-20 minutes and it puked again. I bought a new T stat thinking that might help but when I went to change it, it was empty! Didn't have one, so I installed the new one. Again, 10-20 minutes and it puked. I thought maybe it was because I overfilled it but talking to Frank, I doubt that is all of it. I don't see any water moving in the top tank. I understand there is a baffle in there but I'd still expect to see motion of some kind. No bubbles or anything once full.

I think the heater hoses are really hot but don't feel like they are full of fluid. I'm going to mess around more tomorrow in the daylight but I'd like a kind of checklist because I have an awards banquet at 3 for my kids 4H projects. Sheep and pigs come before hot rods!

[wayne petty]

i worry about cracked heads now.....

got a compression tester...    an air compressor...   a remote starting switch...

disable the ignition system... put it in neutral... fill the radiator.. pull one plug... use the remote.. oh.. wait.. that has a push lever on the floor...

turn the motor over till that cylinder is on top dead center.. pull the valve core out of the end of the compression tester hose...  screw it in the spark plug hole...  charge the cylinder with compressed air... watch the water level in the radiator..  if it rises... trouble...    test them with one plug out at a time..


beware... the engine can and will turn over really fast if the crank/rod is not perfectly straight up and down...  

if you have access to a large water hose..  you might want to verify that all the hoses are free to flow.. and the engine is free of crud..

i guess someone who has more stovebolt  knowledge will know about any coolant transfer tubes...

if you have to pull the head... be sure to order some hylomar from HF.. under sealers...  for both sides of any head gasket...

and ... what temp stat did you put in.?? 160F  180F..  not a 195F  that is too hot for that app...     did you drill a 3/16" hole in it..  a good idea...  lets some coolant through... lets any steam pockets pass without excess flows through the radiator..

wayne...

[wayne petty]

by the way... you might have a look at this link for some chevy info...

http://chevy.oldcarmanualproject.com/

be sure to scroll down when the above link loads...

i did not see any cooling tubes... in the pictures ...   it is still worth asking the question to somebody who builds those everyday...

and it seems the specified thermostat is 140F... not a 160 or higher. according to the factory specs page..  

i wonder if with current concentrations of coolant... if the 160F will work...

i did see a vette 32 valve 140 stat... and one for a volvo marine chevy V6 and V8 that looks like a normal chevy stat... but i only saw a picture .. it was an ebay for 12 bucks..

here is a great pic of how the stovebolt cooling system circulates...

http://old-carburetors.com/1935-Chevy/122.htm

[Ohio Blue Tip]

Frank, Quit thinking, throw the temp gun away and DRIVE YOUR CAR !