I have been having some issues with my coolant guage. It has been happening for a while and its now iritating enough for me to want to fix it. Anyways. I have a 95 gsr motor and a koyo radiator. The car does not seem to be overheating but when I am on the gas the coolant guage drops to the bottom and dances around there for a while. when cruising on the freeway it reads about 1/4 but when I am at a light it goes to 1/2. Do you guys think it is the sensor or something related or is it caused by the bigger radiator. Thanks for any help.

 

What do you mean by "dances around"? Is it making quick, jerky movements up and down, or is it more gradual? If it's bouncing around quickly, more quickly than the engine could possible heat up or cool down, there may be an electrical issue somewhere. If not, it may be a cooling issue.

 

Find the coolant temp sending unit. When it is "dancing", hook up a voltmeter to the coolant temp guage. Check the voltage, if the voltage is dancing around the coolant temp might be broken, especially if the voltage is changing very quickly.

 

Thanks for the replies. The guage is moving fairly rapidly. Only trouble is I think it jumps around only when under throttle. When stopped it just sits right in the middle. Would make it hard to test, unfortunately. I will see if I have a loose connection somwhere either in the cluster or the sensor. If you guys come up with anything else but I'll let you guys know when I work on it tomorrow.

 

its probably a bad guage. mine did that and i replaced the sending unit and it did no good (fortunately the parts store took it back (but i do a lot of business there)). i never did replace the guage.

 

You are probably right on the guage thing. I had no problems with my stock guages before I put in a jdm one. Ill have to throw the old one in to chrck I guess. Is there a way to crack it open and fix it?

 

I would probably check the cooling system a little first, just to rule it out. Engine temperature can cause a gauge to fluctuate pretty quickly. Your case seems a little strange because there is a pattern to the changes. Electrical problems tend to cause more random changes (not always, though). My suggestion would be to turn the heater to high and feel how hot the air gets when the gauge is moving around. Feel it at idle when the gauge is up, and again while you're driving when the gauge is low. Also, does the gauge move when you rev the car up for a while in neutral?

 

I have the same exact problem. Could it be an air-lock in the system that is causing this? When I throttle up especially on a steep uphill my temp guage drops and once i'm at cruising speed the guage returns to normal. When i'm sitting in neutral and rev the engine the guage also drops. Any new info about this problem?

 

Try bleeding the cooling system.

 

Yes there was air in the system. I let the car run with the rad cap off until the fan came on about 5 or 6 times and there was lots of air bubbles in it. The guage is fine now. Thanks!!!

Anyone in southern Ontario, canada have a motor with low miles? I'm looking for the stock replacement for my car. It's a D15B7.