I had similar problems with a civic years ago. especially when you mentioned rusty water after giving it a flush. The previous owner to me ran the car on plain water. no coolant. this rusted the fins away completely on the water pump. the water pump was unable to circulate enough water to cool the engine so over heated. You might need to take your water pump out.
Do you know the age of the radiator? Maybe it's partially clogged and needs to be replaced.Originally Posted by CzEcHy
Good point, when I got my motor it was guaranteed to have 50k or less miles on it, the thing was mint. BUT, I did replace the water pump because that is just what you do when you buy used motors. Good thing I did because even with low miles, from sitting around, the impeller and housing was like red clay. Those impellers are stamped steel, little rust breeders...(some were actually cast iron!)
That sediment can hide in the radiator too, no matter how much you flush it as long as some little bit remains it breeds like an infection.
The PH will be acidic, and just the flow of the coolant thru the radiator and engine can make it actually take on electric charge. Want to see that? just hook your DVM to ground and set the positive lead in the coolant.
Well, you already replaced the thermoswitch in the bottom of the radiator, so you are familiar with how the connector looks like.
IMAGINE this is the connector (sorry don't have a pic of the actual one), take a metal clip, make an "U" and insert one tip in each side, just like shown in the picture. Open your ignition Key and the fans must kick in immediately. If so, then your new thermoswitch might be defective or is not rated for the car.
Power is nothing without control
K I will check the switch and coolant tonight.
Xerex G5 is a good long life coolant to use. Many problems with cooling system corrosion, rust, rusted pump vanes, plugged radiators, blown head gaskets,,, can be traced to not changing the coolant, running only water, etc. The important function here is not just keeping the engine operating temp, but very important corrosion inhibitors with all the various metals exposed in the system. It is what drove the industry to develop long life coolants; nobody paid attention to the fact you had to change your coolant every 2 years! Now we are about 5-10 years for coolant flush and replace for long life coolants.
...lets not complicate the problem here though with more issues: the engine temp overheats only when the car is not moving and the fan does not come on when it should. Also, turning on the A/C, (which turns on the fan) will bring the engine temp back down. This all points to the fan thermo not working. Plugged radiator, or faulty water pump possible but should wait until the fan is fixed first.
Jumped thhe rad thermo switch and... fans turned on.
Jumped the thermo on the thermostat housing, small fan kicked on (with key OUT of ignition)
Rad switch bad? It was brand new
Either that, or you aren't getting enough circulation. The only way to test the switch is to use wire to suspend it over a pot with the probe in water, then heat the water on the stove with a thermometer in it, use a multimeter to see when you get continuity. I should kick in between 195 and 200 degrees. Earlier though, you were saying that the bottom of the radiator was cold after you flushed it. Is it possible that you flushed rust into the tops of the little cooling tubes in the radiator? If so, the best thing to do while you have the coolant drained, is to remove the radiator, hold it upside down, and run water in the lower radiator hose opening (which will now be the one on top) full blast while tipping the radiator back and forth. This will dislodge anything that isn't really stuck in the tubes.
Is it possible you are getting paranoic? What do you mean with car overheating? Is it blowing water vapor through the radiator cap?
Fire up your car and let it get to the max temp, the fan should kick in sooner or later.
Power is nothing without control
An infrared thermometer from Harbor Freight can be enormously helpful in seeing what engine temps are really doing. Both fans should be turning on when the radiator fan switch gets to 194* F.
For what it's worth, you might start budgeting for some cooling system repairs in the near future. I had a rusty system like yours and by the time I was done, the heater core was about the only thing I hadn't replaced.
Dr_Snooz
"I like to take hammers, and just break stuff, just break stuff." - Beavis
1989 Honda Accord LX-i Coupe, 240k miles, MT swap, rear disc swap
Shop manual downloads available here: CLICK TO VIEW
Yeah, the infrared thermometers are highly useful.
Well CzEcHy if you never get the issue resolved we certainly have enough material in this thread for anyone else's overheating issues. Keep it going all the way to a intermitant head gasket leak, which can have this symptom as well.
Infrared thermometer is one of the most usefull tools ever, use it in any trade out there.
I could start a thread just on what all it could be used for!
Last edited by 2oodoor; 11-17-2012 at 06:46 AM.
Forgive me for sounding 13 in the video. I let the car sit at idle for ten minutes till the gauge started moving then started recording
http://m.youtube.com/watch?v=qY1gfOZDeO0
OK, I'm stumped; Unable to open, load, play, or punt with that video in your link.
Try removing the m and .
I saw you touch the top hose, have you felt the bottom one at that point? Is it cold, warm, or hot?
Very hot.
You said that you replaced the cooling fan switch in the radiator. Are you sure you got the A-90 (194 deg) and not the A-108 (226 deg)? Or could there be debris (rust) caked around where the fan switch goes inside the radiator. If both hoses are very hot, it seems that the circulation is good. If you can get or borrow a non-contact thermometer, you can monitor the temp of the sensor directly to see at what temp it is really coming on.
Just a thought, also check your battery ground to transmission. If the ground is not good, it can cause random problems like that.
+1 Most likely it's still the fan thermostat in the bottom of the radiator. It's defective or the wrong temp rating.
If it was a circulation problem (clogged radiator, bad pump, or thermostat stuck closed), the temp would not drop so effectively once the fan came on and the lower hose would be cooler than the top. Reving the engine above idle (2-3K rpm) will increase coolant circulation and bring the temp down quicker.
It's tough to diagnose when you replace a part with one that does not work right... one reason I much prefer to order OEM parts from Honda. Usually Majestic Honda.
He said that he replaced the fan thermostat switch. That was why I questioned which temp rating he put in.
Just went through this a couple days ago. It turned out to be a bad/lazy crusted up thermostat. On a whim I also replaced both fan switches (the one on the thermostat housing with the black connector and the one on the rad with the grey connector). I did check the new switches with boiling water and a multimeter to make sure they were good. Even with a hinkey thermostat both hoses were getting hot after 20min of running but still no fan action (one can force fans by flipping on the AC). Was a bit of a head scratcher. I shall meter both old switches when I have some time over the next couple days and post up the results for your general amusement.
I seem to think the two aren't interchangable connector-wise as well.
Sent from my rooted Samsung
I was wondering about that with the connectors, but my 2g only has the one on the radiator, so I couldn't go check it out. He did say that he replaced the thermostat though. If it were me, I would test the new radiator switch with the multimeter, thermometer, hot water.
Thermostats can be put in backwards too. It can drive you crazy if it's not discovered.
It is weird though how many of these car's fans come on at differnt temp readings on the dash guage.
Last edited by 2oodoor; 11-23-2012 at 05:29 AM.
That's what I would do as well.
Looks like the fan does finally turn on, (in the video) but way too hot already. Either this thermostat is not turning on at the right temp or there is poor circulation of the coolant. (the test in the video points to the thermostat as the temp comes down quite rapidly once the fan is finally turned on)
...we would all like to hear how this is finally resolved. for future reference.
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