Vehicle runs hot at idle but not going down the road. There is no circulation at idle,
Head gasket was replaced twice, 2nd time head was replaced. 3rd time going to replace the head gasket found block needed to be decked. All new radiator, water pump, t stat, cooling fan, all hoses. There is no circulation at idle. If i put a garden hose in the upper radiator hose, than the other hoses and radiator become warm, other wise they all stay cold. Even replaced t stat a second time. Driving down the road no problem. The block was tanked and cleaned when it was decked. Is there any way to put the head gasket on wrong. We are at our wits end.
Could it be a bad heat sensor? If it gives an incorrect reading to the computer, the fans may not activate. Is the overheating showing on the gauge or does it really overheat by sight and sound and smell? It may be no thermostat was put in, or one needs replacement. It sounds like you spent a ton of money, but something little may be the issue.
Check the coolant temp sensor first. You can simply check the sensor by unplugging the harness connecter and use a jumper wire (one end of the wire in ech pin port, make sure you do this on the engine wiring harness connecter). By doing this the wire acts as a good sensor and sends a signal to the pcm ( powertrain control module) to turn the fans on. If the fans still do not come on then check to see if you have 12 volt power going the the fan connecter, if you do not then look for a blown fuse or bad cooling fan relay or even wiring gone bad in the harness . If you do have 12 volt power going to the engine cooling fan and the fans are still not coming on then the fan motor is bad and must be replaced.
Thanks. The fans do come on and I have replaced the t stat a second time just to be sure. Still no change. the upper radiator hose is so hot you can't hold it and the head is too hot also. As soon as I put a garden hose to the upper radiator hose there is circulation, the head cools down and the lower radiator heats up. The temp gauge shows between half and 3/4 but it feels much hotter.
Are you sure the head gasket was not installed the wrong way, if the water jackets are blocked between the head and block that could cause severe overheating. Yes you can install the head gasket wrong it's rare but can happen. The thermostat could also be installed backwards. I'd make sure the spring side in inside the engine if it is installed wrong the thermost at will not work.
Thanks. I know for sure the t stat is right. You can't install it backwards, it will not work, but I checked the function and it is working. that was one of my questions can the head gasket be installed wrong? Someone else did the head gasket this time. I replaced it the first time and there didn't seem to be a way to do it wrong.
Have you replaced the rad cap.
If I remember, the bolts are off set so it can not be put in upside down. Some gaskets are made for universal applications an the water jackets are in different locations on different engines or models of engines. the gaskets ar made to cover the areas where there33 is no water holes, but also cover where they are. Care must be taken to make sure all the coolant flow holes are open allowing the coolant to flow. I'm aware of at least three engines that has happened to. Not saying that is true here, but something to think about. I just replaced the gaskets on my intake because they were leaking oil like a Texas oil derrick. I got the expensive set of gaskets $75.00, and not only did they fit as they should, but it stopped the leaks three other mechanics couldn't. Sometimes you just have to do the work yourself, and don't look at the cost until it is done. It's really hard trying to guess the true issue on line. You're sure the water pump is working as it should? Remember a lot of parts are now made outside of the U.S. and there is a lot of equipment/parts failure. I had to go through 5 power motors for my car window until I got one that actually worked. I also had to replace a new alternator because it really screwed up my electronics. So now just because they are new, does not mean they will work. There are two water pumps also, one totes backward for the serpentine systems, the other rotates the other direction for the old v-belts. Make sure that is correct. Double check everything. When you stated the car runs hot at idea but works at highway speed, to me that is a coolant flow issue or fan issue. My first guess would of been the thermostat, as that is the way it acts when it is stuck. My Vette did the same thing and it was a poor connection at the fuse box for the fans. All it took was the hood to be open to reconnect the wire and the fans ran when the hood was open but not closed. I lost a lot of hair on that one.
If you put cool water on the thermostat/upper hose, it has to be the thermostat, and it acts like it is upside down. You cool it off, and it closes, but if upside down opens and the coolant flows. Like I said, parts even new are now bad. Make triple sure you have the correct thermostat and it is in correct. I've seen this done a lot. Never admit you did it, just do it. Only the entire world will know.
I agree with John it is hard to diagnose a car in front of you. Just for curiosity I will check to see if the right head gasket was purchased. 95 to 98 civics have different head gaskets. Which would mean water jacket holes are in different spots.
I will check to make sure the head gasket you have is for a dx and not an ex two completely different gasket in that an ex engine is vtec.
Ok, I will see if I can check.
Looking for a Used Civic in your area?
CarGurus has 87,376 nationwide Civic listings starting at $1,499.
Search Honda Civic Questions
Honda Civic Experts