Engine runs but overheating...

[deQuincey]

hi

two quick answers:

- I have no clear cause-effect answer to this but they say: do not use a big grain sandpaper to clean the TS, you will destroy the varnish !, in my opinion nothing will change in the electric resistance reading, but i think that if you destroy the varnish, you will increase the deposit of dirty in the submerged part of the TS (subsequently operating life of TS would be reduced)

- the hot air gun is a dangerous tool due to heat being concentrated in a small spot, only that

the name dequincey is ok

regards

 

[deQuincey]

with some pics tsat issue

the two different movements of tstat, 1 (circular opening), and 2 (bottom displacement that will close the by-pass

an example of a(new type of tstat) and b(old type of tstat with the old type of housing)

see the main difference, the old one is longer, so if you install a new one in an old housing, it will not close the bottom opening, and by-pass effect will not be ok

this is the way to close the by-pass, the bottom plate of the tsat has to close the rear opening in the housing

schematic view of the 2 circuits:
(take care, red or blue does not mean cold or hot water)

in blue, the cold start up of the engine, water comes from engine core, and does not go to radiator, because tsat is closed, so it by-pass the housing until the tube that goes to the water pump, and again moves inside the engine

in red, engine warmed up, water comes from the engine, and goes to the radiator (all the flux goes to the radiator, nothing is missing because the by-pass is closed by the rear plate of the tstat), then water is cooled down in the radiator and passes through the tstat in its way to the water pump, and so on

hope it helps

regards

 

[61porsche]

Temp Sender OHMS in car

a. Cold- 100 degrees ( Yes, in the shade of my garage in Texas)- 675 ohms.

b. Warmed up- 175degrees - 47 ohms.

 

[BonitaCS]

a. Cold- 100 degrees ( Yes, in the shade of my garage in Texas)- 675 ohms.

b. Warmed up- 175degrees - 47 ohms.

Thanks for all your help!

I did hit the TS with the a wire wheel to varnish is now gone... Will replace eventually unless it is the culprit.

 

[Bwana]

Me too

My '72 CSi ran great as far as cooling goes since I bought it 9 months ago. In just the last week it's starting to heat up when idling in traffic. And it's much cooler outside now than last summer in the same situations.

How do you check the clutch fan operation? I have the original 5 blade red fan. It spins freely with the engine stopped and all warmed up. From the comments above, there should be a difference between the turning resistance from cold to hot?

Can these fans be repaired? If not, what is a good replacement?

 

[bmw art car]

My '72 CSi ran great as far as cooling goes since I bought it 9 months ago. In just the last week it's starting to heat up when idling in traffic. And it's much cooler outside now than last summer in the same situations.

How do you check the clutch fan operation? I have the original 5 blade red fan. It spins freely with the engine stopped and all warmed up. From the comments above, there should be a difference between the turning resistance from cold to hot?

Can these fans be repaired? If not, what is a good replacement?

Your fan clutch is gone. The fan is not supposed to spin freely, when the car is warmed up.
now it's a good time to upgrade the fan and waterpump.
PM me your car info. I can help you with the parts

 

[Honolulu]

+1, or 2, or three, on the fan clutch. It should be NOTICEABLY more resistant to freewheeling when warm. When cold if you flick the fan blade with your hand it may spin one to three times. When hot, it should stop within about 1/4 turn.

Fan clutches are not serviceable to my knowlege.

I suspect your tstat is okay, but do verify the correct stat to housing match.