jpuleo

Hi everyone I am new to this site, I have a 99 civic si and I have had an overheating problem recently. Recently I have changed: water pump, thermostat, radiator, coolant overflow tank (due to a small hole that caused it to leak antifreeze), and the head gasket is new done about 1500 miles ago. I am confused because once my car heats up to normal operating temperature it's fine, it's only when I drive it for a short amount of time and then, for example stop at a stop light for about a minute or so, the gauge will slowly rise and just keep rising until I start moving once again and it will just cool back down to normal temperature again. I'm thinking this might be because my electric fans appear not to turn on, ever. If so can anyone tell me how to diagnose this problem and how to go about it? Thank you any help will be appreciated.

tony_2018

After replacing all of that did you bleed the cooling system for air? Is your radiator fan kicking on like its suppose to?

jpuleo

Yes I just changed out the relay and all the fuses for the cooling fan and it now kicks on when the temp gauge gets up to about 3/4 of the way, but the cooling fan seems to do no good as the temperature keeps increasing as i sit still and if I let it, it will just keep getting hot until the guage goes all the way up

tony_2018

Your thermostat is stuck closed and won't open, verify that the thermostat is functioning like it should. Yeah that requires you to take it back out.

NotARaCist

iTrader: (1)

Original radiator? Original fan? Any modifications at all? Did you use any "head gasket fix in a bottle" **** in your engine before replacing the head gasket? And I'll ask again, since you didn't answer the first time: Did you bleed your coolant system properly? If you think you did, tell us what procedure you followed.

jpuleo

The whole motor is new I have just replaced all the internals the WHOLE motor and I mean everything is new and replaced. The motor has about 1300 miles on it right now. Everything is brand new I changed every single component in the cooling system. I have not bled the cooling system because I do not know how to do that, could you explain to me how I would do that on this car? And what temperature should the thermostat open up at? Should I put it in a pot of boiling water? Is it supposed to open if it were placed in boiling water? Thanks.

jpuleo

The only modifications on the car right now are AEM v2 CAI and a cat back exhaust and header

NotARaCist

iTrader: (1)

Put the front end on jack stands, or park it facing up a hill. Set the heater blend to full hot. Remove the radiator cap. Start the car, and let it run for 30 minutes, keeping the radiator topped off at all times. That's how you bleed your coolant the easy way.

jpuleo

Ok I will try that tomorrow, I'll give you an update on how it turns out. Thanks.

KSavaiki224

Try the relay. Had this issue a couple weeks ago and it is solved now. Good luck.

NotARaCist

iTrader: (1)

Yep, let us know how it acts after a proper bleed. There's a high possibility, given all that you've changed, that you have a small air pocket either caught at the fan switch sensor, causing it to not do what it's supposed to do, or a small air pocket near the ECT sensor, causing it to give a false reading.

jpuleo

Cool guys thank you, good advice I'll try all of your suggestions, and KSavaiki I just replaced the relay today and the fan now kicks on but still heats up. I'll give it a proper bleed and then see how it works I'll keep you guys updated. Thanks

jpuleo

Update: so I have bled the system and the car was fine all day yesterday. I took it out again today and the car was okay for the first hour or so, but once I went to a parking lot and was sitting in it for about 5 minutes on the phone with the car on, the temp guage slowly started to rise again. I don't know what the problem is here I cannot figure it out. I will check for leaks but I haven't seen any at all but it's worth a shot, do you guys have any suggestions? I can't think of what the problem could be here. Thanks.

joey1320

Why was the engine overhauled?

Who did the work, a reputable shop or some hack?

Have you done a compression test after rebuild?

Have you actually seen the cooling fan spin?

Have you checked the thermostat for proper operation?
(if you don't know how YouTube it)

If you want, completely remove the thermostat and run the engine without it and see what happens.

jpuleo

The engine was completely rebuilt because the previous owner seized it somehow, once I opened it up there was metal shavings everywhere. Cooling fan turns on as I said before, I didn't think of doing a compression test I don't see why that would be necessary, a good shop did the work on the motor I've been going to them for years. And I kinda ruled out the thermostat because I figured that if the thermostat was stuck closed the car would overheat all the time, even when I drive it. It does not overheat when I am driving only if I have the car on and sitting still for more than about a minute.

joey1320

Reason I ask about the compression is because you could have a small coolant leak via the head gasket and hopefully a compression test would reveal that.

If you have a new radiator, water pump, fans and thermostat, and they are all working, then those shouldn't be the problem. So now time to start looking into the engine for possible signs of internal damage.

Good luck!

KSavaiki224

The relay was my issue man.

joey1320

If you are going to help, why not actually do so...

What relay are you referring to my man?

KSavaiki224

The only relay that has to do with cooling. The radiator fan relay. Not being rude but figured you would've guessed which one I was referring to considering the issue.

Former User

In tech forums, it's best to provide unambiguous advice. That's joey's main point.

joey1320

Understandable but according to the op, the fan comes on when supposed to, so one would conclude the cooling fan relay is working properly.

KSavaiki224

He says when he sits still it starts to overheat. When he is driving the air is cooling the vehicle. I will almost guarantee it is the relay(radiator fan) that is the issue.

Former User

A bad fan relay is theoretically possible if the fan doesn't run, but it's not all that common.

KSavaiki224

Only reason I'm saying that's more than likely the issue is because I just went through the exact same thing two weeks ago. Replaced a lot then it ended up being the relay.

OP just swap your relays around and see if the fan ends up coming on doing that. If so, that's the issue.

NotARaCist

iTrader: (1)

He already said that his fan is working. If the fan works, the relay isn't the problem.

OP, you said you replaced "everything". What fan do you have on there? Is it shrouded?