Low Coolant light problem

[roadrunner19va]

I have a 1991 5.0. Everyonce and a while my low coolant light comes on. The resevoir is low so I add water. about 2 weeks later it comes on again. I will have to add water. I do not see it dripping anywhere nor do I see any smoke from my exhaust. I pulled the plugs and there is not deposits on them so I do not think the head gaskets are shot. The car drives great all the time. I checked the oil and it looks fine. It'd not milky. Anyone have a problem like this or have a possible clue on what can cause this? Thanks Travis

 

[Roland69]

sounds like the symptoms of a heater core.....atleast the same symptoms that I had.

 

[Roland69]

here is a pic of the "weep hole" that drains coolant or moisture from the hearer box. I found mine dripping one hight after getting fed up with the coolant light comming on every few weeks. I did this at night with a blue LED keychain light and the green stood out like a sore thumb cuase the light made it glow. I took this pic cause this question is kind of common and some people didn't have a clue what I was talking about.

View attachment 430110

 

[mob]

Does your car smell like burnt coolant? Thats a clear sign of bad heater core. Honestly sounds normal though. Do a search next time, the sensors on the resivors go bad, or get dirty. My resivor is always dry. Try this, one morning go and fill up the radiator. Leave the light on for a few days, and if the car isnt over heating, another morning morning get up and check to see if the radiator is still full. As long as the radiator is full and the car isnt overheating, then ignore the light. If it starts overheating and is losing coolant, check out the radiator. If that dosent work, do a pressure test and if there is a leak IT WILL show.

 

[cjnecessary]

I have had 93 and my 89 at different times develope a small hole in one of the cores in the radiator that I could not find until the rad. was out of the car.

 

[vristang]

Put a pressure tester on the cooling system.

with pressure on the system, while the engine is not running, it will be much easier to find the source of the leak.

jason

 

[Roland69]

the sensors are known to get dirty and make the light come on

 

[speedytang]

If you read he has been adding water so it is not a faulty sensor. I would say either heater core, radiator small leak or your burning it from a intake gasket or head gaskets. Kinda like a water injection kit it is turning to steam and since the leak is so small your not showing in the exhaust or causing pinging. Put a pressure pump on the radiator and is if it drops pressure then put a dye in the radiator run the car then let it cool down some but make sure it is still warm and pressurize the system and use a black light to find the leak.

 

[bubba-dough]

Check the weep hole on the water pump as well as what others have said.