Running hot

[paper1122]

I was at the Central Florida meet/ride yesterday and the car was running very hot. A couple of times the needle touched the "red". The fan does not seem to be coming on soon enough, nor is it staying on long enough. One of the guys suggested the fan relay. Does anyone have experience with this or suggestions?
I had to turn off the A/C early in the run which kept the car cooler but it hung at the 3rd bar the entire time after that.
I've been reading up on clarks but it doesn't talk about the location of the relay's.
Any help is appreciated!

On a side note, it was great meeting everyone, it was a very fun ride.

[mikepellegrini]

If you turn on the A/C (working A/C), the car will run hotter than usual because of the power draw on the engine. If your car is close to over heating, always turn off the A/C and it will cool down, somewhat.

If the car is really starting to overheat, then turn on the heater at full blast hot and that will help cool the engine. If the discharge from the heater (on hot) is NOT hot, then you're really in trouble because it means there isn't enough coolant to run the heater. Shut the engine off at once!

With your car, if the fan isn't coming on at the proper temp, then it's more likely the problem is the thermofan switch.

Thermofan switches are cheap and easy to install. They come in different temp ranges as well - I put a lower range switch in my car (so the fan comes on earlier - 75C).

Clark's has good procedures for testing both the A/C relay and the thermofan switches.

If I remember correctly, the A/C relay is #3 (blower).

[paper1122]

Are the relay's just the general relay that PP sells as "general" relays for $5.50?

[mikepellegrini]

No, the wiring (internal contacts) must be different - it's a separate part # - 944-615-113-01-M100

http://www.pelicanparts.com/catalog/shopcart/944M/POR_944M_ELswch_pg1.htm

[Cebu]

If the temp lowers when you turn on the A/C indicates second radiator fan comes on. Fan relay or temp sensor in (upper left) of radiator is faulty.

[paper1122]

I put in the 75 degree thermoswitch. It seems to have solved the problem, the car runs much cooler and the fan comes on much earlier, in fact it runs nearly constantly. (Go figure I'm in FL). How long shouuld the fan run after the car is turned off? It ran for probably 10 mintues, I'd be a little concerned that it will drain the battery. Anyone know how long the fan will run for?

[mikepellegrini]

On early cars, the one fan supposed to run until the radiator gets below the cut-off temp - usually just a few minutes, but it depends on how hot everything is.

[Rasta Monsta]

When these 2.5 rads get to be 25 years old, they commonly flow quite poorly.

Take it to the rad shop for a flow test.

[paper1122]

The radiator was replaced less than two years ago according to the PO. But getting it flow checked really isn't a bad idea.
Do you think I need to worry about my battery being run down by the fan?

[idontknow]

Originally Posted by paper1122

I put in the 75 degree thermoswitch. It seems to have solved the problem, the car runs much cooler and the fan comes on much earlier, in fact it runs nearly constantly. (Go figure I'm in FL). How long shouuld the fan run after the car is turned off? It ran for probably 10 mintues, I'd be a little concerned that it will drain the battery. Anyone know how long the fan will run for?

Ten to fifteen minutes is about how long it'll need to run in the summer, and no it won't affect the battery. Mine has the same setup it hasn't failed me yet.

[paper1122]

Excellent, thanks for the help "idontknow".