CLUE

thanks, I want to give it a good clean flush, I see there's people on here that know their stuff, I'm just thinking of flushing it myself, but I want to do a proper job, I know it can be time consuming and if you don't do a good job then what's the point. I've done a flush on older trucks before, don't think I used a flush solution for that I just drained the old coolant into a pan, pulled out the reservoir and cleaned and then filled & drained rad with water a couple times and then topped it up, would that be sufficient enough on my car (1991 mustang gt)? If anyone has any info to give me on helping me through the process, like what coolant to use, and/or a link to instructions to do this for my specific car would be great. Remember it had been sitting in a garage for 2 years before I bought it as well, so far I've changed oil (synthetic) and oil filter and K&N air filter, put on a flowmaster exhaust and now this low coolant light came on, it may be running just a bit hot, although the temp gauge on dash is always normal. If you can give me some pointers that'd be great.

jojobanks

personally when I flush my coolant I do it by taking off the thermostat housing, removing the thermostat, and sticking a water hose in according to the flow direction and just let it flow till the water looks clean.

Some places use a machine to flush the coolant and that's cool and they don't have to remove the thermostat, but if they're doing it any other way then they're not really cleaning the system out very well.

Your low coolant light is there for a reason. if there's not coolant hitting the temp sensor then your gauge isn't going to tell you if you're overheating. Just add some more water/coolant to the reservoir and it should go off. If it doesn't then your sensor is probably bad.

CLUE

Ok, how can you tell which direction the flow is? Is there arrows on the hoses or something, or do I have to find out the rad type and look it up? That would mean putting the hose in the rad cap or through the bottom (direction), am I correct? I also read somewhere that you can get some sudsy water and brush the outside of the rad, parralell along the fin direction. Is there anything I should take note of when taking off the thermostat and putting back on? I might just bring it to my buddies house, it's a ways away but he used to be a mechanic and he has stands and tools and a shed to do it in. Thanks, I want to learn how to do as much as I can myself to save some cash, I will give it a go tomorrow and if there's any issues after that, then I will have someone take a look at it.

ITALIANO66669

i remove radiator cap and upper radiator hose from radiator,start car and let it run with the water hose in the cap hole and with the upper radiator hose off you can see the water coming out of the radiator but wont come out the hose till the thermostat opens,itll open probably 4-5 times then itll be clear.stick upper hose back on top off coolant and done.thats how we used to do it till osha issued fines for dumping coolant on the ground.now we use a machine.

jojobanks

when you take out the bolts for the thermostat housing you may need to clean the threads on the bolts and/or chase the threads in the holes. A lot of times people will get silicone in here when reinstalling everything and the holes are pretty easy to strip. If this happens you gotta yank the whole manifold and drill/tap new holes. not fun.

animalkracka

i'm having the same issue with my 95. it's kinda wierd because the light comes on when the car is first started and stays on. if i shut it down and start it again after it's warmed up the light goes off. what do you think could be the problem? i can't see any visibe leaks or pooling but i do smell coolant.

CLUE

Ok, so I flushed out my rad and I put in a new thrermostat today. I feel much better about it now, although the low coolant light still came on, why would it be doing that still? I drained the rad and put in the new thermostat, Canadian tire didn't have the gasket for my thermostat housing and Lordco was closed when I went there, so I had to use the old gasket, will I have to re-take it apart because I didnt change the gasket? It doesnt seem to be leaking at all, so I'm wondering if it's ok? I put in some prestone flush stuff and ran the car with the heater on full blast for 10 minutes, then turned it off and drained it, filled with water one more time, ran it another 10 minutes then drained again. Then I filled it with a 50/50 mix of coolant and took it for a little drive, after that I took the rad cap off and burped it a bit then topped up the rad again. For some reason the low coolant light came on again shortly after, do you think replacing the rad cap, or the sensor would fix this? I was thinking of just buying a new radiator cap and if that doesnt work then a new sensor, it's not overheating at all, temp gauge sits in the middle of normal range and doesnt go much higher. I know that it has a new thermostat and it has been flushed and filled with new coolant, so I'm not as worried about it anymore, but the light does kind of annoy me, so I just want to fix it, what do you think?

AdderMk2

Your coolant is low... add some.


Man, I guess it is called an idiot light for a reason.

The_Dude

Your sensor is probably bad. Did you try cleaning it?

Tony71502

The coolant expands and is no longer "low" when the car is warm. Notice the cold/warm level on the coolant reservoir. As Adder said, add more coolant.