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This is a honda forum, why are you asking us about your miata? As per forum rules you need to list the year, model, and trim level of your car, plus any modifications.

 

My bad, I forgot to list the car. Its a bone stock d series sedan. Its my dd. The Miata doesn't leak coolant.

 

Most likely the U shaped heater hose by the thermostat under the intake manifold. I highly reccomend the $50 ebay silicon hose kits



And

 

Thanks! I will check that! I also recommend you a new radiator on the red car lol! normally when they are brown like that they are on their last leg.

 

Yep. Been there done that before

 

1996 Honda Civic Lx d16y7 automatic

I am having an issue with my civic overheating sometimes. It really has only happened when coming to a stop or stop and go traffic. I have an 120 mile round trip for my job. I can drive all the way to work or home and it be fine till I slow down or stop to get food and then it will happen. I have replaced the radiator cap, thermostat, fresh coolant, and bled the system on a steep incline with the heat on. I tested the fan switch and it turns on when I jump it. The fan turns on when the car gets hot. Both upper and lower radiator hoses get hot and pressure. The coolant has gotten low previously before the radiator cap replacement. It seems to stay full now I believe. I will have to keep an eye on it and check it lunch. If its low ill check for a leak but I do not believe it has one.

other possibilities.
-Is it possible for the sensor that tells the fan to turn on to be going bad? Like it works sometimes and not other times. It seems to turn on when bleeding the system but maybe after hour long drives and it gets warm it doesn't?
-blown head gasket, if all else fails ill rent a tester this weekend and see....hopefully not.
-water pump, I'm guessing this would be okay but any way to check it?

Other Ideas??

 

Check the heater hoses by the thermostat housing near the intake manifold. It is common for one of them to have a small leak and cause issues.

The thermostat switch is on the thermostat housing, you could replace it but it sounds like it is working fine.

Normally with an overheating condition my first advice is to replace the thermostat and inspect the hoses as you replace the thermostat and bleed the system.

 

Yes the fan sensor switch can go bad like that. Test by unplugging it and put a jumper wire in the plug-- that will make the fan run all the time the key is on. (if the fan does not come on with the plug jumpered, check the motor, fuse, and relay).

Test drive with the fan running all the time. If it doesn't overheat when standing still any more, replace the fan switch.

 

I will check for a leak by the thermostat housing. The thermostat has been replaced and the cap.

As for the whole switch thing.
I have jumped the switch before and it turns on the fan. I guess there is a thermo sensor (switch) that tells what the coolant temperature is and that turns the fan on when hot. If the car is overheating the fan should always be on correct? Like no matter how long its hot the fan should be on? If the fan works but is not always on when overheating then the thermo sensor is bad?

this is the part correct?
Duralast Coolant Temperature Sensor SU4006- Read2Reviews onDuralast #SU4006

 

One thread per topic. Related threads merged.

 

Im having exactly the same issue ----2000 civic with d16y7.
Ive bled the system (on an incline with heat on) twice
Ive changed the thermostat + temp sensor
Installed new radiator cap (Radiator fairly new)

I literally just purchased a headgasket + waterpump from ebay (both honda OEM) and figured Id tear it down and just do the waterpump / headgasket as this is my daily driver and its cheaper for me to spend $100 in parts and not worry about any issues.
Id *really* prefer to not do them. I had a feeling it was a failing water pump but I also am pushing 200k so it probably isn't a terrible idea to replace. The water pump has about 60k on it (Aisin brand)
Ill follow your thread, please update if you find the solution.....and I hope for both our sakes it isnt a HG or Waterpump.

 

Do a compression test, and a block tester to verify headgasket leaks.

If you have hit full hot on the temperature gauge you should be worried about the head gasket. If you've caught the car going towards the hot needle before it got there you might still be safe from a head gasket.

Ron is quick to say head gasket for a reason, if you've driven it around over heating all the time I guarantee you blew a head gasket.

 

Sorry, I forgot that I had created this thread previously. Thanks for merging.
I have never drove around with it hot. When noticed I pull over immediately. The car has never made it over 3/4 of the way to hot. So hopefully no head gasket issue. We will see what happens. I will update when I figure it out or find more info.

 

The 2 hoses themselves? The heater core? Replacing the clamps is a waste of effort, replace the coolant lines and be careful not to kink the pipe the are connected to. You were warned.

 

No.
There are ways for the engine to overheat and the fan won't come on, even though the fan system is working.
This is why you should test drive with the fan running all the time to rule out the fan not starting being the actual cause of the overheating.

 

And repair all leaks so the system stays full. Before each trip when the engine is COLD, take off the radiator cap and confirm the radiator is staying full to the top.

 

Is there an easy way to inspect the hoses on the back on the intake manifold. Near the firewall. Theyre almost impossible to see from above with the hood popped. Can you see them from underneath the car? I think one of them may be leaking.

 

Use a mirror and/or raise front end on jacks.

 

So they are visible from underneath? The oil filter or other accessories aren't in the way to much?

 

You can see all the heater hoses in this picture. The large U shaped one closest to the intake manifold is the one that typically leaks

Which is why I always replace all hoses anytime I get a new civic. They are like $12 each at an auto parts store, cheaper to just get a generic ebay hose kit. The silicon hoses are suppose to outlast the car, so far all 4 vehicles I've used them on have been great successes

 

I will try and take a look at those hoses today. I can see drips on the transmission normally. Not a bunch just some. Is there a change that something else is leaking other than heater hoses. Like the other really small hoses or the intake or something?

 

Sure, but you should be able to identify the source of the leak.

 

There are 2 to the throttle body, but as mentioned once the engine is warm you should be able to spot the leak. If it's a small crack it won't leak until it gets warm which is what caused my overheating problem which causes me to say just replace all the hoses