My car is running at 220*+ at cruise speeds at times it gets as hot as 240*(maybe even hotter, the gauge stops at 240*). It will stay at about 190* sitting in the drive idleing all day long but as soon as I rev on it the temp start to rise then no matter how long I let it idle it stays at the temp it got up too. I changed the radiator hoses, had flex hoses, now it has molded hoses. Took the thermostat and tested it in a boiling pot of water, it opened at 180*, also drillied a hole in it to keep from air locking. I have a 3 core maverick radiator and a electric fan w/ shroud. With the car running and the cap off the rad I can see the water flowing, put it seems to be flowing in "sprits" it will flow for about 15-30 seconds then it seems to stop for about the same amount of time, is this normal? Sorry for the long explanation, I just can't figure this out.
The temp is definitely not normal ( but you know that) but for it to flow then stop then flow, yes that is normal, that is showing that the thermostat is opening, letting the water flow then closing once the water has cooled enough, then when it heats back up the thermostat opens up again. I really do not know what to say about why it is heating up when the car is running at highway speed and not at an idle, most cars I have seen overheat do the exact opposite. Do you think that maybe you gauge is messed up? If it were me I would try another gauge FIRST then go from there just buy a cheap gauge and the thermo-couple that goes with it and check it that way. You did say that you have an electric fan, Is the fan blowing in the right direction?? Also is the fan coming on when you are running at highway speeds? Maybe when you are driving it out on the road the airflow is enough to keep the thermal switch cool enough that the fan doesn't come on when driving at highway speeds?? If that is the case then it definitely isn't going to cool back down by letting it sit and idle, #1 because the electric fan isn't going to push enough air across the radiator to cool it back down, (it is made to maintaine a Temp not to lower the temp after an overheat) #2 like I said at an idle is when most cars overheat to begin with because the waterpump isn't circulating the water very fast and you do not have the cool air flowing over the radiator. My bet is going to be that you have the electric fan mounted to the engine side of the radiator "BLOWING" the air toward the front of the car and when you are driving the air flow hitting the front of the radiator is working dead against the fan so you are in a sense trapping the hot air at the radiator. if the Fan is mounted to the engine side of the radiator you should have it "pulling" air through the radiator, and if it is mounted to the grille side of the radiator you shoudl have it "blowing" air through the radiator toward the engine. Of course all this long winded posting is pure speculation. Hopew you get this figured out
Thanks, I have checked the fan several times and it is pulling the air through the radiator, if I put a peice of paper on the front side of the radiator the fan will hold it there. The fan is operated by a manual switch, so it always on when I turn it on. I will check the gauge though, but when it reads hot on the gauge it is also dumping water too so I believe the gauge is working fine. Shouldn't the thermostat stay open for longer than 15 seconds though. The car was at 200* last time I checked it was still flowing for 10 second "sprits" I am thinking maybe I have a "weak" pump (if that is possible) but don't want to change anymore parts before consulting the maverick gurus.
It's either the T-stat or the water pump. If you continue driving it hot like that, you're gonna have yourself a blown head gasket...
well it sounds like you have the bases covered. I don't know exactly how long it should stay open, but if the temp it at 200 degrees and it is still cycling then I would say something is wrong with the thermostat. once the temp goes over 180 and is staying there the thermostat should stay open. One way to see if it is the thermostat or the pump would be to completely remove the thermostat and run it without a thermostat in. If the pump is ok it should do almost the opposite of what it is doing now. It will run really cool when you are running at highway speeds because the pupm will continuously circulate the water through the radiator, and when you come to a stop and let the car sit and Idle it will heat up pretty quick because there is not enough air flowing across the radiator to cool the water before it returns to the block and gets heated up more. I don't know if you would consider it to be a "weak" pump but it is certainly possible for a blade or two or three to break off the impeller inside the water pump and cause it to not circulate the water as well as it should. It is also very possible for the waterpump to maybe have an undersized pulley on it and that would certainly cause it to overheat when running at highway speeds.
'Only other thing it could be, besides what I previously mentioned, is a corroded or clogged-up radiator...
I never thought of the sending unit wire on the intake as being a conductor and giving a false reading until I read it on the other cooling thread. Have you tried isolating/insulating the wire? I am having some cooling issues also (no boil overs though just reading hot) and my wire just lays on top of the intake. Scott
That was my first thought. Does your new lower hose have a spring inside to keep it from collapsing? That's exactly how it would act, fine at idle but when the water pump sucks harder at a high rpm the hose collapses. I've seen some newer molded hoses that claim not to need the internal spring, but I've seen them fail, too.
I started out with a flex hose that had a spring in it, the motor also over heated with it too. The new molded hose doesn't have a spring, where could I get one to put in it. If the hose is collapsing would I be able to see it collapse while holding the engine at crusie RPMs?
Had a similar problem myself. Turned out to be air in the system. Had to "burp" it by using one of those funnel type fillers that hooks to your radiator and filled it while the engine was running and removed it once it cooled. Did this a few different times and worked well each time.
That is one of the things I hoped it was, this last time I drilled a 1/8 hole in the thermostat to stop air lock from happening. I am changing the water pump and putting a new thermostat in it. Hopefully it won't overheat anymore. Thanks for all the input.
I keep reusing the spring I have from an old hose. Once I even twisted a wire coat hanger to make my own.
Is your engine built up any?? Is your radiator original(it could be plugged up with calcium deposits)Try flushing it out before you throw money at it.
