jonathan13

Okay I just got my si running not too long ago and I have an issue with it warming up. I can let it run forever and it doesn't ever get passed the bottom line on the gauge showing that it is warming up.. (though it will climb slightly). But then after driving it for some time and coming back to let it sit it will slowly start to climb and actually show that it is a little on the hot side- more so than it should be and it will stick there. Doesn't act like its too hot- no water in the overflow, no steam from the radiator- only issue is at this point it stops wanting to idle and sometimes will die on startup or while sitting in a still position after driving (like at a stop light). Another weird issue with it is that when it is starting to warm up but isn't fully to operating temperature yet the fan will kick on like its already hot- This made me think maybe my gauge is reading wrong but then if so when it was reading slightly hot it was actually fully overheated and would have been showing signs which it was not. I am stumped. I have replaced the fan and thermostat and have let it sit for over an hour running with the radiator cap off to bleed the system but the thermostat never opens because it won't warm up while sitting still. Any ideas or suggestions will be great appreciated. Thanks in advance.

jonathan13

oh and i also wanted to add that when it gets in the hotter than normal position it takes hours upon hours for the gauge to show it is cooled back down- even if i have the keys in the forward position to keep the fan on with the motor off.

jdeemseerx

when it is running does the top hose get hot? are you sure you didnt put the thermostat in backwards or perhaps get a faulty one? any CELs? make sure there is no coolant in the oil.. does it look low after a long drive?

Former User

I think the 1-wire ECT sending unit under the distributor may be bad. Unplug the sending unit connector and ground its single wire to the engine. In ON(II), does the needle in the dash temp gauge now rise more rapidly?

jonathan13

ill try that asap, should i let the car cool down first or do it while it is already warm.. i replaced the thermostat switch today as well and also noticed my hoses to the IACV were a tad bit leaky and causing it to loose pressure so that may be the cause- i fixed those as well.. and the thermostat is in correctly and there are no CELs.. oil is very clear- no coolant in it.. both hoses get hot.

Former User

The test can be done when the engine is either hot or cold, though testing a cold engine might be easier.

jonathan13

well i havent had time to test it yet but after all the work i did yesterday it is still taking forever for it to warm up and it wont get all the way warm. it has yet to get on the hot side even with the ac on with it idling but today has been a cool day with some rain so i need a very hot day to see if its going to get hot or not. and as for the test.. so i just need to unplug the sensor and cut the plug off to ground it and then when im done just reattach the plug with a soldering iron?

Former User

Don't cut anything. Unplug the sensor and use a piece of wire to ground the sending unit wire to the engine.

40mpg_dx00

Any codes?
Are we sure this isn't a head gasket issue? I have seen '02 civics kick ECT sensor codes as a result of internal leaks from the gasket. In fact, my buddy just did one the other day that had the same symptoms like it wanting to die at stoplights and poor gauge response.

Former User

It's possible, though the OP might want first to check the coolant level in the radiator and reservoir and also bleed the cooling system of possible trapped air. The test I suggested was simply to ensure that the dash temp gauge is functioning properly.

jonathan13

i have bled all the trapped air and i havent had any loss of coolant except for what i mentioned above about the lines to the IACV- at least no loss to my knowledge.. doesnt seem to be burning out the exhaust or anything and it is running fantastic otherwise.

shawn_crx

x2

I heard the eg civic are known to have bad temp gauge

jonathan13

this is a 99-00 si.. i was thinking the same thing but i have never in my life seen a bad gauge.. but we shall see. i appreciate all the help guys

jonathan13

well no more overheating.. i think im gonna leave it as is for now. its running perfect so i honestly dont have a problem with it taking some time to warm up since the overheating issue is gone and it idles fine now. must have been the small coolant leak and the thermostat switch. thanks for the help everyone

tw1tch

I have the same problem with my si, and a buddy of mine also had this problem. I think it's due to the needle "sticking". Sometimes when I shut the car off, the needle stays in the normal operating temp, instead of falling back to the fully cold position like normal. I would advise you to spend the 50 bucks on a nice Autometer water temp gauge. Peace of mine.

jonathan13

im gonna swap my cluster out for a buddies and see how his gauge acts and if its like it should be ill will probably drop the cash on a gauge.. mine sticks at operating temp. for quite some time after i shut it off.

tw1tch

I've only had one 96-00, but I doubt that is normal. Sometimes my needle goes right to cold when I turn it off, but other times it takes a while. That tells me it's gotta be sticking, since there's no reason it would sometimes stay and sometimes go right down. Sounds like that could be your issue. Dunno about the dying issue and the overheating, though. Mine would stay on cold forever, and then it would literally shoot up to operating temp in 3-4 seconds. If you can hit vtec after a few minutes of driving but it still says cold, it's definitely a faulty reading since vtec won't engage without proper oil pressure that you lack when it's too cold. Good luck.