To start off its a 1997 crv awd auto. Has 204xxx miles on it , Has been maintained very well. !!!!!!Engine runs like a dream no issues except!!!!!!!!!!!!!!

The problem started a couple months ago. I noticed the temp gauge went up to H, my first impression as common sense would tell you the engine is overheating. Well as I gave it gas the gauge would go to normal. Then 2 weeks later went to h and stayed , I pulled over and popped the hood and no steam or boiling over coolant was there as it normally appears in this situation. I let it sit about 30mins and drove home . I have replaced my thermostat, temp sender temp switch and also flushed the cooling system . It had normal flow and no blockages. Tried cranking it up and let it idle for around 30mins thermostat open as it should and I also got all the air out of the system as well. Temp was fine, so I went for a test drive down the street and within a mile temp gauge back up again. I pulled the water pump and timing belt and replaced with new timing belt, water pump , and tensor pulley and also changed the crank seals and cam seals valve cover gasket . ( timing is perfect also ) When I finished I cranked it up and It runs very smooth as always but still done the same stuff.. I noticed when I turn my lights on and high beams ,radio , int. lights, use power windows , and turn the ac on , I can flip for example my lights on and off very quickly and my gauge will move down than up a little . But still always when I turn everything off and drive it still maxed out the temp gauge . I have a theory it could be maybe something with my electric system but than again don't want to chance it with the temp gauge going up either. The belt on my alternator has wear and cracks which I going to replace this weekend but the others are fine. It just seems when the electric system is under strain the gauge goes up quicker. But when I sit at idle without touch the gas is stays normal until I drive!!!!!!!!!

Sorry for the book but I am stumped here and wanted to tell what I have replaced and the problems.
I have tried shorting the cooling fans and driving just to see if it would change anything and nothing fans are good.
My oil looks no coolant mixture good and compression test was right were it should be. Head gasket should be good.
No oil leaks either , engine runs smooth and quiet.


Thanks in advance , any other things I can check that I haven't listed ?

 

Wow. I think you pretty much covered everything there that I can think of. ECT sensor wasn't mentioned unless you called it something else but it sounds like a gauge/wiring issue to me.

 

Kinda sounds like a wiring issue, or maybe a ground. If I was in your situation, I would use my code reader, using live data, watch the coolant temp there and compare it to the gauge. There are 3 coolant sensors on a honda. The small one wire sensor on the head under the distributor is for the gauge, next to it is the one the ecu uses to dictate fuel multipliers and set idle, the 3rd is on the thermostat housing and that controls the fans.

The gauge on the dash should rise quickly till 170°F, then not move till about 215-220°F. Just trying to give you an idea of the numbers you will be seeing if you aren't aware

 

[QUOTE=goldsy;49412300]Wow. I think you pretty much covered everything there that I can think of. ECT sensor wasn't mentioned unless you called it something else but it sounds like a gauge/wiring issue to me.[/QUOT

yep the temp switch- I going to mess with the wiring today and see what happens.

 

ok I will give it a shot thanks .. I will let you guys no what happens.

 

The 2002 and up CR-V's and Elements do not have a distributor or a separate sensor for the gauge. The ECT sensor between the block and the head is used for both the ECU and the gauge.

 

He stated 97 crv, that's what my reply was geared towards

 

OK guys- I went out the morning and cleaned all ground pulled the temp gauge wire , sprayed wd40 and cleaned with a very small wire pipe cleaner. It had some corrosion done in the connector. I cranked the engine let it run for about half an hour . Everything fine a usually , Until I started driving down the street . Again fine til about a mile and same thing except when I come to a stop it drops to normal when I go rises to max. I'm sorry but engines that are over heating just don't drop like that from a stop. So I'm thinking its a bad cluster. I'm going to look one up and see if I have enough cash to order it today. I let my wife keep driving it but if it indeed ever does overheat I don't want to take that chance with her driving around and mess the head up or crack the block either. What do you guy think order the cluster and see what happens ? I hate process of elimination !!!!!!!

 

This is how the temperature gauge works:
The coolant temperature gauge has two intersecting coils wound around a permanent magnet rotor. Voltage applied to the coils, through fuse 25, generates a magnetic field. The magnetic field, controlled by the coolant temperature unit, causes the rotor to rotate and the gauge needle to move. As the resistance in the sending unit varies, current through the gauge coils changes. The gauge needle moves toward the coil with the strongest magnetic field.

The coolant temperature sending unit’s resistance varies from about 137 ohms at low engine coolant temperature to between 30-46 ohms at high temperature (radiator fan running).

As long as the car really is not overheating and there are no large air pockets in the cooling system; basically the problem you describe can be due to:
• Temperature gauge sending unit.
• The wire that goes from the sending unit to the gauge. If there is an intermittent short in this wire, such as being caused by wire insulation melted or nicked and the bare wire touching chassis/body ground, it will cause the gauge to move up.
• The gauge may be faulty. The gauge is separately replaceable from the rest of the instrument panel.


Do you have a multimeter or ohmmeter, so that you can do a resistance test of the sending unit?

Unplug the Yel/Grn wire from the sending unit. Measure the resistance of the sending unit between the positive terminal of the sending unit (tip of the sending unit) and engine ground. When it is cold should be about 137 ohms. If the engine is at operating temperature, it should be about 30-46 ohms.

 

Oops, my bad.

 

Figured it out guy it my voltage regulator go figure!!!!!!!!! when I unplug it my temp it perfect when I plug it up it spikes . replaced the regulator a few min ago and good to go. Never seen that before. I had someone from another forum give me that advice. but thanks for all your reply's.

that's going to be stuck in my head forever to check that as well.

 

Do what I said with the scanner. It will give you an actual temperature reading in a numerical value. If it fluctuates you know the engine is getting hot, if it doesn't then you can start trying gauge related parts.

 

What voltage regulator? In the alternator?

 

yes in the alternator . through me off to but I tried everything on the cooling system and also use my buddy's scanner as requested and it was good. I tried what the guy said and it worked. blew my mind but makes since with the problems I was having. I have seen that before in other things but never with the temp, that why is crossed my mind.

 

I can see it being possible, but I'm surprised you didn't have other issues too.