I just bought a 73 and it gets hot really fast. Just a small trip around the block, maybe 2 miles and the needle buries. When I turn the car off I hear a boiling sound coming from somewhere in the engine compartment.

Another thing is When at idle the oil pressure goes down to zero and then when you accelerate it goes to normal. I checked the oil it was a red color and really thin. Does this mean that there is a crack in the head???

 

About the overheating thing...have you checked the antifreeze in the radiator? You might have to add some, or maybe throw put some more water in it. The boiling noise you hear might be where one of the hoses from the radiator is breaking, and it is leaking on the manifold. Mine done this when I first got it. Eventually the hose ended up busting and I had a mess :)
Also, does your radiator fan work? I don't know if '73's had electric fans or not, or that could be your problem. I recently had to replace the electric fan motor on mine, and I put a 180 theremostat on it while I was at it. Now she nevers gets over the 200 mark. You might want to consider putting dual electric fans on it.


[Modified by corvettemaster, 3:51 PM 8/8/2002]

 

Could be a stuck closed thermastat. Also check to see if there is any oil residue in th radiator.

 

Are you sure you weren't checking the transmission oil? It would be red and thin by design. Red and thin moter oil would be bad. As to overheating, just take first things first. Drain it, flush it, refill it with water only, replace thermostat with a 180, check fan clutch with cold engine by spinning. Should spin easily cold and tighten up when warm.

 

Yikes!! This doesn't sound good!! Lots to check....do you have enough coolant in the system? Thermostat stuck in closed position? Cap holding pressure? Rad clogged (external or internal)? Clutch fan (presuming it has the stock fan) working properly? Rad/shroud seals in place? Condition of hoses? Any leaks anywhere or steam?

Would help by knowing what your cooling system/drivetrain is comprised of and what has been replaced/modified and whether any of this coincided with your new problem. With the boiling noise, I'll assume your guage is correctly indicating overheating but a heat gun will verify.

Oil pressure....usually means an old tired engine with clearances beyond spec. However, oil pressure will read low under extreme heat conditions like you are experiencing, but even a tired engine should hold 10lbs. Thinner oil (5W30, for example...will read lower pressure than thicker oils). If you address your heating problem first, you may find that at normal operating temp's, your pressure may read more normal. Maybe....maybe not.....

As for the red colour....I don't know. Coolant in the oil will usually show bubbles and foamy looking because oil and water of course don't mix. Red in coolant is usually evidence of corrosion....is this the colour of your coolant also? If so, could be head gasket, crack in head, crack in block....none of which is good news.....

Was this car regularly driven before you bought it or is it a project??

 

First, for the overheating, you can take the thermostat out and take the time to drain the radiator and verify that the block drains. Then put water in the neck and verify that the Radiator fills to the height of the neck so you can say the water is going thru the block and in the radiator via the lower hose. If water flows, then button up without thermostat and check for overheating. If still overheats, Bad news.

Second.. Motor oil is Black.. I agree with, verify it is not transmission fluid. You may want to drain and replace just be be sure someone did not put transmission fluid in the Oil.

My oil pressure did not read and would jump up during driving and it was partcially plugged hose and that messed up the gauge. I mounted a cheap oil pressure gauge under the hood, right below the louvers, so I could see it from the diver seat. Then drove the car and verified correct pressure. Then pulled my indash guage and cleaned with de-greaser stuff until I was satisfied. Replaced the hose and reconnected the indash gauge and all is fine.


[Modified by rreavis, 9:36 PM 8/8/2002]

 

Sounds like you might need a new head gasket....

 

Ummmmm...I hope this car was a bargain :bb