Mike1971

HELP! I have a 1999 Honda Civic EX. I recently had the head gasket replaced, and ever since the radiator fan will not come on, resulting in overheating. Here is what I have done to check fan system operation.


1. I direct wired the fan to the battery. fan came on.
2. I jumpered the fan switch on the thermostat housing. Fan came on.
3. I replaced the cooling fan switch on the thermostat housing. NOTHING!
4. Thermostat was replaced when the head gasket was done. My lower radiator hose is heating up, so I am assuming I have flow through the thermostat.
5. I put the car on ramps, radiator cap off, heater on, for 30 minutes to bleed any air. the car stayed at normal operating temp the whole time. As soon as I turned the heater off, temp climbed. Fan did not turn on.


I am out of ideas. I don't want to run a toggle switch. I want it to work properly. Any ideas?! Thanks.

mk378

Test drive with fan jumped to be on all the time and confirm no overheating. If it still overheats, there is another problem (lack of coolant, clogged radiator, thernostat doesn't open, etc.)

Former User

Did lower radiator hose get hot?

Mike1971

Yes the lower hose got hot.

Former User

Some possibilities:

Air is still stuck in cooling system.

Head gasket install was bad or head/block is warped. (Rent a block tester kit.)

New fan switch is bad out of the box.

Mike1971

I understand how air in the system or bad switch would prevent the fan from coming on. How would the head gasket/ head/block prevent it from coming on?

Former User

Exhaust gases injected into the cooling system from the cylinders would have the same effect as air.

slomofo

iTrader: (1)

Coolant not flowing where it should.


But seriously, I think he's trolling you.

Former User

Troll implies intent.

mk378

I suggested doing a very simple test, this advice has been ignored.

Former User

OP - Don't ignore mk. He's the real deal!

Mike1971

Not ignored. I am at work right now. I will try your suggestion this evening and post results.

Mike1971

I got the fan all wired up with a toggle switch in the cab. It got late so I will test it out tomorrow. Assuming this keeps the temp normal, what would you suggest I do next?

Former User

Run the test and go from there.

fcm

Hmmmm, if fan runs when you jump the fan switch, then it can only be the ECT switch that is the problem, and because you said you replaced it, I can only assume the new switch is DOA. 94

tony_2018

He'll have to test the ECT to confirm that.

Mike1971

Ok I ran with the fan on constantly and it still wants to overheat. My radiator has seen better days, so I am thinking I should change that next to try and correct the overheat problem. The thermostat is only a couple weeks old, and i can hear it clicking when i squeeze my lower radiator hose. Also my lower hose gets hot, so i would assume it is working properly, is that correct? I guess the fan issue will have to wait. Unrelated, can anyone suggest a good lube for my throttle cable? It feels kinda grabby...

Former User

Do you have 50:50 coolant in the cooling system? How does it look?

Replace radiator and flush cooling system. Then go from there.

Have you already removed the TB and cleaned it? If not, do so.

Mike1971

50/50 in there and looks pristine. Hate to sound ignorant, but what is TB?

Former User

Throttle body

Mike1971

Will do. Is that to help with the overheat issue, or just good housekeeping? Will that help with the sticky gas pedal?

Former User

^

Clean thoroughly with brake or carburetor cleaner, re-install with new $2 gasket, and torque TB nut/bolts to spec.

Auto or manual transmission?

Mike1971

Manual

Former User

When you decide to clean the TB, also consider removing and cleaning the IACV attached to the back of the intake manifold (IM).

Mike1971

Ok so I finally got a radiator, but I believe it's for an A/T. It has 2 brass fittings the bottom that I assume is for transmission fluid cooling. Does it matter? Is it losing a significant amount of cooling?