In your photo where your finger is pointing to, that is not ECT (Fan) Switch A; that is the ECT sensor.



The ECT Switch A is not shown in your photo. I've attached a photo of the location of Switch A. If jumping the connector for Switch A with the ignition ON doesn't run both fans, then with a spare piece of wire attached to terminal no. 2 (Blue wire) of the connector, touch/connect the other end of the spare wire to body ground and see if both fans run with the ignition ON.

 

Just a thought, but typically when using the heater blower motor causes the temperature to decrease it is a sign that the thermostat is not opening. The temp sender isn't sending a signal to run the fans because the it isn't receiving hot coolant to activate it. If this is an intermittent issue, your thermostat is about to go....it just hasn't quite yet. Again....Just a thought.........sean

 

Ok I jumped the right ECT Switch A and with key on both fans come on.

Drove with it jumped and it still started to overheat eventually.. however did take about a quart of coolant after that, may need radiator as a result now too. Thermostat and radiator and go from there?

 

Yeah still slowly overheats with coolant topped off and fans running, unless I keep the heat on, which is very toasty.

 

And now I can't keep up with it even with the heat on. Still with me here? Whatever it is should be easier to figure out now if I end up taking it in. Just replaced the thermostat a few weeks ago while doing the new cyl head, timing belt, etc. It was a spare thermostat that came with the car, hopefully that's the problem.

 

It could be the thermostat. You said you have to add coolant, so a coolant leak is a possibility. Why did you have to replace the cylinder head?

Try getting a radiator pressure tester as a loaner tool. Remove the radiator cap. Verify that your system holds around 15 psi of pressure.

 

I had just bought the car, it wasn't running right, I thought it just needed valve cover gasket but it lead to doing many things, I plan on keeping it.

In my experience since all I've driven is a cb7 for 15 years, it can be a little low on coolant and have no fans running and it should be fine especially in the fall. Only leak I can see is it steaming out and dripping down the overflow tank, which is completely full. The heat should not be as hot as it is. Taking it to freakin dealer.

 

It could just be the thermostat. It could also be a faulty cap if you are loosing coolant and can't figure out where. However, if the head was just replaced, did you do the work yourself or did you have a shop do it? I ask because that could be the problem. If the head was not torqued properly, either step up, sequence or insufficiently then you could conceivably be loosing compression into the cooling system when the engine heats up. The head could have, or already been warped or cracked. Look in the coolant expansion tank when the engine is running and see if there are bubbles coming up through the coolant consistently. If so, have someone rev the engine for you and observe if the bubbles increase in volume or frequency. If either occurs you have a compression leak into the coolant system. IF a shop did the install, you may have some recourse as they should warranty their work. If they don't you still may have some recourse in small claims court. If you did the install yourself....well....you might be SOL if the head is damaged....sean

 

Well you may be right, dealer concurs. It was a new head from a head shop and I had a guy do it. I'll let you know the verdict.

 

Yeah, your overflow (expansion tank) should never be completely full. It should only be as high as the max mark on it. If you keep it there and it ends up higher or lower than when you filled it, you'll know you have a problem somewhere. One symptom of a blown head gasket/warped or cracked head will be loss of coolant from the expansion tank over flow. Bubbles in the expansion tank is another as is engine overheat. All three pretty much confirm the head as the source of the issue.

One thing that occurs with loss of coolant is air pockets in the coolant system. What happens with an air gap in the coolant is the coolant will boil into super heated steam which in turn will wreck a head or head gasket. The super heated steam will actually cut into the aluminum of the head and eventually blow out a head gasket or even cut a hole to anywhere outside the cooling jacket. I have actually pulled a head and seen exactly this sort of thing. Almost looks like someone went at the coolant passage with a plasma cutter or cutting torch. It gets that bad if left unchecked. If yours ran low on coolant or was never bled properly after installation of the head, that could be the source of what ever failure has now occurred.....sean