So I have a 1970 olds with some year old gas. It has a fan shroud and clutch fan and when I drive it runs around 160 degrees. When I idle however it it goes up to 200 to 250 degrees unless I give it gas then it will cool down. Anyone have any suggestions?

 

Are you sure that you don't have air in the system? Check the clutch. Spin it. If it stops with only a few turns it's fine. If it keeps spinning freely change it. Do you have air, how many blades on the fan?

 

Sounds like a classic bad fan clutch.

Easy to get at the auto parts store.

- Eric

 

Thanks guys. I hope it is just the fan clutch do you know how hot it needs to get to engage? Also how close to the radiator it should ne?

 

if you have a fan shroud the blades should be sticking out the back of the shroud about 5/8", maybe a 1/2".

 

About 190ish at the clutch.
When it starts running above 200, pop the hood and stand to the side and poke your head just under the hood. If your hair ain't getting blown all around and you do not hear the roar of air being blown, it is time for a new clutch.

Mine did not spin freely when stopped but it never engaged either.

 

250 is bad, over 220 is bad!

 

mine with a 455 will blow newspaper out of the garage from six feet away.

 

I have a stock 7 blade fan but no clutch.

 

I think it might be a combination of thermostat and fan clutch. The top hose of the radiator is really hot while the lower one is warm but not burning which makes me think the thermostat is not opening to let more water flow. Also the fan clutch doesn't spin very freely when the engine is cool but the new one doesn't seem to either. I will try the thermostat first when I get to work on it tomorrow.
Thanks again for all the help.

 

If the top hose is hot, then the thermostat is open.

- Eric

 

Check your base timing and distributor advance.

You may also have a faulty water pump that is not moving enough water at idle speeds.

Has this engine been bored over?

 

No the engine has not been bored over it just has a little bit bigger cam.

 

i think the flow direction is from the motor past the pump, thru the thermo., out the upper hose, into the top of the rad., down the rad., into the lower hose, back to the pump inlet. is this right? sounds good to me. so if the upper hose is way hot, and mine is at operating temp., and by hot i mean you can't rest 'yer arm on it while setting the timing, ouch! the lower one should be alot cooler, that means the radiator isn't plugged and your probably getting enough airflow. i was told if you grab the fan blade and spin it by hand and it rotates a few times around and seems to have some drag on it then the clutch is working, it should also appear to sort of have lag. i also have the seven blade fan and a optional deep fan shroud, and a four-core rad. plus the air seal kit from a '74 on mine. i think the rad. uses a 15# cap too. a 40/60% mix may help, i run a 50/50 at least, probably 60/40, the rebuild guy said olds. 455's have a nasty habit of cracking the blocks by the motor mounts if left outside in cold climates. mine was bored .020" with 9.5 to 1 forged pistons and a cam with .454"/.485" lift, 205 degrs. dur./ 112 degr. C/L, seems to work fine. fun to drive too. they make a water pump that has an enclosed impeller, this may or may not help, that rad. can only dissapate so much heat.

 

Thanks guys it looks like my issues are from the carb once I leaned it out it is running a lot cooler. Now I have another problem though. Once the engine warms up it seems to flooding or not getting enough gas it will start to sputter then die. If I half throttle it will run but when I floor it seems to cut out. If I let it sitand start it again it seems to run fine if going freeway speeds but once I start driving im traffic it will start the stuttering again.

 

I would go back thru my tune and verify dwell and timing settings, pull plugs, clean and regap, and then reset my carb!

 

does it still have the quadra-bog carb. on it? they have a fuel filter inside that piece on the carb. that the fuel line connects to, maybe replace it. and look inside there and make sure there isn't something plugging it, like piece of old filter/wash./spring. maybe there is an inline filter somewhere, people often did that thinking the OEM set-up wasn't good enough or something. maybe the sending unit/pick-up screen in the tank is plugged. no big deal dropping the tank on these cars, and good time to check and replace those short hoses and clamps back there.