Rep Power: 0

So I’ve got a 93 eg d15b, coolant overflows to res but doesn’t return when cold, I’ve also never heard the fans turn on and I know they work because I’ve jumped them from the coolant switch, I have also bought a new coolant switch and coolant temp sensor. Would the headgasket cause the coolant to overflow and not return and the fans not to turn in any help is appreciated

 
Rep Power: 230

The fans aren't related to the head gasket, directly. Those should turn on when the vehicle reaches the right temperature.

But the fans not turning on could have caused the head to overheat, warp, and unseal the head gasket.

When the head gasket leaks, exhaust gas displaces the coolant in he cooling system and it overflows into the res.


If while the engine is cold and you open the radiator cap and hear/see bubbles, the head gasket is definitely leaking.

 
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Would that be the reason the fan would not turn on tho? The circuit seems to be fine according to my testing, unless I’ve just so happened to have gotten a bad coolant fan switch from auto zone. I don’t want to replace the headgasket and the fan still not turn on and ruin it again.

 
Rep Power: 223

Try an OEM switch

 
Rep Power: 519

It can and will if circumstances are right for it, but there may be other possible causes as well.

Radiator fan does not run until its thermoswitch is hot enough to close its contacts, and the temperature of the liquid at that switch is not necessarily going to be the same as engine temperature shown on the gauge in the dash.

If you suspect the head gasket is blown, do tests that would prove or disprove such.

 
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Let car idle for like 30 minutes filling with coolant and reviving. Bubbles started coming out whenever the car was at operating temp and when I held The throttle. Was I seen it the first time it started bubbling every like 10 seconds. So I guess no doubt the headgasket is blown right? Last question would be would the headgasket cause the fan not to turn on

 
Rep Power: 519

Didn't the fan ever run during this time?

Not necessarily. Like I said, if you believe it's blown then do tests that would prove or disprove such.

If the fan never turned on and the radiator cap was not installed, the liquid in the engine could have simply been boiling.
Or maybe it was expelling trapped air pockets.

An engine can run hot and/or overheat with less than a quart of liquid missing from the radiator.
Any loss of liquid can compromise cooling system efficiency.
There is very little reserve capacity in those small systems.




In and of itself, no. But if the fluid level inside the engine has dropped, then yes.
When a cooling system is low.......the engine itself could become hot enough to suffer damage, yet the fan thermoswitch might never get hot enough to turn on the radiator fan. This DOES happen.

 
Rep Power: 0

Theoretically if I changed the headgasket do you think that would solve the fan problem?

 
Rep Power: 519

If head gasket is not causing the problem, then why would replacing it fix the problem?

Test, don't guess.

 
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Btw no fan did not turn on during that time