Need help. My coolant is overheating and i caught in time while driving i turn my heater to max heat and the coolant gauge went down to normal temp. The coolant gauge goes when the car is moving, at stop it stop. From time to time I could drive and nothing the car is just fine. No oil in coolant and vice versa for the oil. No coolant lost, so far i'm thinking maybe my thermostat is going bad! i need to replace my water pump and waitting for slowboy to send my kit!!! But in the mean time I just like to find out the problem!!! let me know what your think

 

Just go to the auto parts store and purchase a thermostat. It's the quickest and cheapest start to trouble shooting.

FFR, if you're buying factory parts, you might want to try JNZ Tuning. They have great prices, reasonable shipping and lead-time is accurate from what they tell you on the phone.

 

if it already over heated once--good bet you need a head gasket now aside from what caused the overheating to begin with

 

^+1, start cheap and work your way up to the more expensive things. I'm going to say that most likely the water pumps has not gone bad yet, but anything is possible.

 

the coolant gauge never got in the red
and thanx for the help

 

doubt it. also depends on how much you drove on it while it was overheating. plus the OP stated that it never got in the red so i doubt the headgasket is fried.

OP - how old is ur coolant? did you ever change it? over time the coolant looses its ability to properly cool down the engine and needs to be changed.

i would take everyone elses advice and change the thermostat first. its easy and also cheap. good luck

 

I had no luck getting a thermostat from a parts house. The books they have end up supplying a Lancer thermostat which looks the same but is smaller. If you go this route, have the Evo thermostat with you.

 

If there's no leaks at all and the level is full, make sure the fan is kicking on and also the thermostat. If it's the pump it takes no time at all for it to get to the red and it will not go down quickly with the heater on.

 

were you running the a/c when it got hot? What fan setup do you have? Thermostats are normally designed to fail open so worst case scenario you have no heat and the car won't go into closed loop.

 

While driving i happen to look at my gauge and saw my coolant going up I let off the trottle and kept my RPM down as soon as i did that the temp started to go down. I was at about 80 mph on the highway. I was not using my A/C neither the heater. When I came to stop light coolant started to go down sligthly. I'm picking up a thermostat in the morning and I will go from there

 

I would say the coolant is about 10000 miles but I will flush the system and put new antifreeze

 

head gasket my friend!

whenever you remove the head, check the surface for warp, also check the valve seats v4 u install that ish back! also is good if you check the block, if the temp went all the way to the hell, u might warp you block too!

 

is there any other way to detect a BHG. If I run a compression test should that tell me if head gasket is blown! BHG would i have oil in coolant or coolant in oil?

 

dude just star your car, if u cant stay @ idle ure ****ed!

 

I would make sure the fans are working and it has plenty of coolant. You didn't recently change fmic's right? Can you think of any work that has been performed recently prior to the problem?