Up and Running, but hot

[phocus]

Got my 67 40 up and running these past few weeks, with one problem. It runs hot, idling after maybe 7 ,8 minutes. I crank her up and get a loud fan noise, radiator is cool to the touch, after 8,9 minutes, the loud fan noise goes away (slower I guess) and immediately gets hot. Bad fan clutch?

75 2f, low miles, new thermostat (not boiled and checked, new rad cap (16 lb), air burped.

[Sharp38]

How do you know it's hot. If the radiator is cool to the touch, it could be a sender/gauge problem. I would get in heat gun and see what it says. If the radiator is cool to the touch but the engine is hot, the thermostat is restricting flow through the radiator. Take out the thermostat and test. Your fan noise is probably the clutch. Might be worth changing out. Don www.wolfcreekrodworks.com

[phocus]

Hummmm, don't have a heat gun, how much are they? Spent all my duckets on cruiser parts. The engine is cold, just started, 9 minutes later its hot, 12 minutes later (at idle) ready to boil over. same results with thermo out. Any way to lock up the clutch, just to verify clutch problem?

[gmarshall7]

Have let it run w/ out the radiator cap? Circulation?

If your fan blades are clean enough to stick a piece of tape on(different color) on just one of the blades, it may give you a visual on the speed change of the fan...

Dallas?? Turn me onto some trails !!

[phocus]

Hi gmarshall,

great tape idea!, I did run it without the cap, and i do have circulation.

I will turn you on to a trail, when I solve the hot problem, and get a windsheild, hopefully soon.

[gmarshall7]

Originally Posted by phocus

Hi gmarshall,

great tape idea!, I did run it without the cap, and i do have circulation.

I will turn you on to a trail, when I solve the hot problem, and get a windsheild, hopefully soon.

Cool. We used to ride bikes on the powerlines and gas lines off of 61. Probably cabled off nowadays.

PM huston53 for a windshield. May have one.

[phocus]

Ok, Just purchased a laser heat gun, I am running 210 degrees at my temp sender (located on the top rear of the head). I am not running any coolant at this point, due to testing (will it make a huge difference?) what temp should I be running?

[phocus]

Correction: after idling about 20 minutes (no brakes)
temp at sender is 240 degrees,

I set timing, adjusted valves, added coolant, thermostat working, fan clutch working, running a shroud.

[inkpot]

Originally Posted by phocus

Correction: after idling about 20 minutes (no brakes)
temp at sender is 240 degrees,

I set timing, adjusted valves, added coolant, thermostat working, fan clutch working, running a shroud.

Howdy! I would bet on the fan clutch being the problem. It may appear to be working, but at high temps it should not slip at all, keeping the fan at full speed. When you shut off the engine when it is reading 240 at the sender, can you turn the fan with one finger? To me that would indicate that it is not locking up for max cooling. John

[Degnol]

Don't know what your ambient temp is there, but I suspect in the mid 80's? Try what InkPot says, then put a box fan in front of the radiator on high and see if that makes a difference. Next suspect, maybe the headgasket

Ed

[malcb]

Use your laser temp gauge/gun to check the temp into and out of the rad on the pipes. At idle you should hardly be needing the radiator fan. You need to know the pump is woring.

PS by "added coolant" you do mean you had straight water and added antifreeze/corrosion inhibitor don't you? Antifreeze/corrosion inhibitor will not make any noticable difference unless you put more than a 35% mix in, that would actually make the rad less effective.

[Dirtsquirt]

I try to vent the highest point on my engine water passage.
on small block chevy's i usually break the seal on the thermostat housing and lift thermostat. when filling for the first time to avoid an air bubble.

If its a head gasket I think you should see combustion gases coming out of your radiator with the fill cap off.

I would do a compression check and check for gases b4. I got crazy and started taking things apart.

[phocus]

Ok, doing a compression check this morning, will let you know what I get.

I did notice one strange thing with my new fangled laser heat gun:
exhaust header #1 = 345 degrees
" " #2= 535 "
" " #3 = 740 " ????
" " #4 = 525 "
" " #5 = 495 "
" " #6 = 365 "


maybe a blockage on # 3 exhaust or head gasket at #3

anyway, thanks for the suggestions guys.

[phocus]

update,
compression readings
1...2...3....4...5...6...
135,130,135,130,130,135

temp reading at sending unit 235 degrees
top rad hose, 190
bottom rad hose, 160
@ 800 rpm

How do you diagnose a bad water pump?

any ideas?

[inkpot]

Originally Posted by phocus

update,
compression readings
1...2...3....4...5...6...
135,130,135,130,130,135

temp reading at sending unit 235 degrees
top rad hose, 190
bottom rad hose, 160
@ 800 rpm

How do you diagnose a bad water pump?

any ideas?

Howdy! If your top radiator hose is around 190* continuously,after it's warmed up, then your fine on temps. Your thermostat is flowing just enough thru the system to keep it at that temp. The water will always be just a bit cooler that the steel parts it is flowing thru. It doesn't sound like it is overheating to me. John

[phocus]

I ordered a new 4 core rad from Radiator Barn , got in two days, problem solved.

I'm just a tight ass, did not want to spend the $.