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Overheating Nissan 240SX

A co-worker has a 1993 Nissan 240SX. It used to overheat continually. When he stopped at the side of the road the radiator was cool. He changed the thermostat and the problem continued. He bled the coolant system to ensure all air was out of the lines.

Finally he took a 1/16th in drill bit, drilled several holes in the thermostat. When that didn’t work he drilled even more holes.

Question 1: There must be a better way than this gum and duct tape solution. What is it?

Question 2: Wouldn’t he be better off just to take out the thermostat?

"When that didn’t work he drilled even more holes."
You Didn’t Say Whether Or Not That Solution Fixed The Problem.

You also don’t say whether or not the car consumes coolant.

The thermostat is there for a reason. It gets the car to operating temperature quicker and keeps it at optimum temperature which is better for the engine, MPG, and the environment, not to mention cabin heat.

This co-worker could be fighting a blown head gasket on this old bomb for all we know, based on given and missing information. An overheating engine and cool radiator leads me to believe that air being introduced into the “closed” cooling system is keeping the coolant from properly circulating.

More information is needed in order to get meaningful advice.


Just spoke to Terrence, he said the overflow container has captured all the coolant that boiled out of the system. The overflow tank has been very hot. However, when he touches the thermostat housing it’s cool. That’s why he drilled the holes in it.



It’s hard to tell without seeing the vehicle firsthand, but the entire motor should be hot, including the thermostat housing.

Try removing the thermostat, install housing without one (doesn’t have to be a perfect install), flush the system, and install an OEM stat from a dealer. This will take some time, yes.

If the antifreeze is boiling, and the radiator and overflow tank are hot, then the fluid is moving through the system…which tells me the water pump is moving it.

Even though a thermostat is new, doesn’t mean it’s actually doing its job. It’s fairly rare, yes, but they can be bad right out of the box.

Double-check all the belts. Is it possible he’s somehow managed to install them incorrectly, and the water pump is turning the wrong direction?

I’m not sure that investing any additional money in repairing that car would make much sense.

After all–if it used to “overheat continually”, the likelihood of engine damage is very high.
Whether it might have a warped cylinder head, or a breached head gasket, or scored cylinder walls, or–worst case scenario–a cracked engine block, damage to the engine is almost certain if it overheated on several occasions.

Time to walk away from this old money pit, IMHO.

Hoes this car have an electric fan? Is it working? How is the radiator? Are the fins of the radiator clogged? How about the water pump? You should see flow into the radiator.

Sounds to me like you either have a clogged radiator…an Air bubble in the system…Or a blown head gasket…WHich would introduce…Said Air Bubble…

Hard to diag over the net, but I am thinking the head gasket…PRIMARILY…because this engine has been overheated many X…it takes only ONE TIME…to damage the cylinder head to make the Cylinder head gasket fail…This is where I would be focusing my energy. If you t reat it W Blue Devil and the prob goes away…YOu can than start saving to do the job the right way…which is remove the head, have it cut and install the new Cyl Head gasket…

You can fix it properly…which is mechanical…or try Blue Devil…

AFTER you verify that it isnt the radiators ability to shed heat…but my monay is on the Head Gasket…Hapns all the time…People just think the Temp gauge is a friendly reminder of how hot the engine is

CSA is on the Ball as usual… Or just because he agreed with me…take your pick. LOL…I think hes right

AT this point BLUE DEVIL THE THING…its 60 bucks and will FIX IT…so that you can save for the proper repair…Blue Dev is permanent tho…works like a charm when the issue is minor…such as this case…where the gasket has failed from the water jacket side of things. YOu are getting cylinder air pumped into the rad system in this instance…thats the lesser of evils in the head gasket failure manual, which I have happened to read and re-read many x in my life.

Old Car (As In - “Washington Slept Here”), Continually Overheated, Belching Coolant . . . My Money’s Still On The Horse Named Blown-Head-Gasket To Win.

Will the coolant from the overflow bottle be drawn back into the radiator as the car cools down after being parked or does it remain in the bottle, allowing the level in the radiator to drop ?

Just spoke to Terrence, he said the overflow container has captured all the coolant that boiled out of the system. The overflow tank has been very hot.

We need to know this from Terrance. I hope Terrance has been checking the coolant level in the overflow bottle and radiator each time the car cools off several hours after one of its episodes. Knowing where those levels start out and end up is important information. The car needs to start out with a full radiator and all air purged from the cooling system and then when it cools it should still have a full radiator and no air in the cooling system.


Replace the water pump.
Sounds like it has failed internally, probably with a damaged impeller.


yes, there is a better way. Diagnosis.

At this point i’d do nothing until I looked for evidence of a headgasket leak. That can be verified with a pressure leakdown test.

If despite the fact that his odds of having a headgasket leak are about 99.99765% at this point his head gasket is still good, he’ll need to start by checking the water pump, the radiator, and the hoses. One of them is probably blocked.

And, of course, he’ll need a new thermostat. Removing the thermostat will NOT fix the problem.