Surging issue, possibly relating to cooling

I've got an '88 2lt injected Accord.

It had not been running a while and had a problem with overheating and surging.

I've replaced the water pump, which had a bad bearing, and attempted to bleed air from the cooling system. I undid the bleed cap near the thermostat housing and filled the radiator until coolant come out. I then started the car and brought it up to temperature. It was there that it started surging - idle rising and falling. The temp gauge also started to rise to about 2/3rds but the thermo fans did not kick in.

The old coolant is in pretty poor condition - very, very rusty brown - so I plan to do a full cleanse of the system, but I was just worried about this issue with the fans not kicking in and the engine surging (checked fan fuses and they're ok).

Would anyone know where I should start with trying to figure this out? Many thanks!

I bleed the coolant while the car is running the the T stat is open. Just like bleeding brakes on a car in a way.

The IACV controls the idle and is mounted on the intake manifold. Two small coolant tubes run in and out of it. Again with the car running try and loosen one side and listen to air escaping,that should fully fix the idle problem. I think its the tube nearest the throttle body is coolant out.

https://i.ebayimg.com/images/g/cngAA...MKC/s-l640.jpg

public service note: the above image I stole from E bay the product appears roached as noted the corrosion on the coolant pipes.

I have reasonably decent luck jacking up the front of the car when filling coolant. For the fans, there is a diagnostic chart on p. 23-6 of the '89 manual in my sig. It's worth consulting. The cooling fan system is surprisingly complicated on these cars.

Take the cover plate off the idle air control valve, it's the thing with coolant lines on the bottom of it on the back of the intake. There will be two phillips head screws holding the cover plate on. Get a quarter and using said quarter spin the slotted thingy inside it up or down. It's threaded in there. Move it up and down a little at a time and hold your hand over the valve to keep air from bleeding out each time you move it a bit until you find the sweet spot. When you get to the point the idle stops surging with your hand covering the valve, put plate back on. Put a new o-ring on the cover plate if you can.

Hey all! I now have this same issue. The car one day decided to start surging when its warm and the temp gauge would rise and the cooling fans would not turn on unless I turned the car off or if I turned the ac on. Fans would turn on if I did those things but surging wound not stop. I had this issue once before and I changed one of the temperature sensors (the one for the computer) and that fixed it but that was 10 years ago and I don't remember witch one it was.

Check your coolant level.

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Originally Posted by Dr_Snooz

I have reasonably decent luck jacking up the front of the car when filling coolant. For the fans, there is a diagnostic chart on p. 23-6 of the '89 manual in my sig. It's worth consulting. The cooling fan system is surprisingly complicated on these cars.

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Hey Snooz, is that page specific for cars with AC? also tryna work out why my 1 radiator cooling fan doesnt come on. Cheers.

Do they not come off the same wire? If you follow the loom down from the fans you will find the fan pigtail comes off at a plug. See if theres more than 2 wires in there. Mine are wired together, but my car isn't fancy... so sounds to me like you have a bad motor.
Don't even bother with the stock fans though, they suck and theyre loud. I am able to get 2 flexalite fans on mine, I think theyre 1ft.

Disclaimer: I did not check the manual to conclude that, but you could just wire them together anyway, but maybe not with the stock fans.

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Originally Posted by ShiRen

Do they not come off the same wire? If you follow the loom down from the fans you will find the fan pigtail comes off at a plug. See if theres more than 2 wires in there. Mine are wired together, but my car isn't fancy... so sounds to me like you have a bad motor.
Don't even bother with the stock fans though, they suck and theyre loud. I am able to get 2 flexalite fans on mine, I think theyre 1ft.

Disclaimer: I did not check the manual to conclude that, but you could just wire them together anyway, but maybe not with the stock fans.

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I only got 1 fan on my deck, it works when I short the connector like it says in manual (pg10-9) but doesnt want to come on otherwise, so assuming not motor, I replaced the thermosensor itself (located in bottom of rad), although need to test the old one. Found out recently on some engines theres two temp sensors by dizzy, Tw and other, thoughts are I may have the other instead of the rad one. Will perservere and look at alternative fan arrangements.

So only one fan comes on when the sensor kicks it on or you turn the AC on? Which one is it? The big one?
I am looking at the diagram on 23-4, they should both come on under any circumstance, unless the timer unit doesn't apply 12v to the small one all the time. They ground on the same path, thats why mine come on at the same time, but there is no timer unit to cut 12v... I am surprised there is any complexity to this circuit. Yeah, use 2 separate, replaceable relays for the fan motors, but run the 45w headlights through the stalk switches.
So you could have a bad timer unit, but it sounds more likely that you just have a bad relay. You are shorting the connection for them, but 12v is always present on the motor side of the circuit. The timer unit only switches 12v for the relay coil.
I have no idea what test you are running because my manual does not have a page 10-9... Just so we are on the same page here is the one I use, it should be the same one Snooz gives around. https://www.dropbox.com/s/h7ao48yvb8...anual.pdf?dl=0

Think i've misread this thread, havent got AC on my car, the only fan is the rad cooling fan, which has been playing up a bit. Page 10-9 is this one. I got it from the pauldesign link.
Don't wanna hijack the thread either sorry.

Attachment 10463

We mix up threads all the time its fine gives it it a facebooks feel. Dont worry about it.

AC cars have two fans so it's a bit confusing I guess when you only have one.

I would look into changing the relay next it should be available. There is a control box under the passenger seat. If thats messed up it is hard to find a relacement.

You may just have to rig up a switch make it run before your trip and run it your self.

We mix up threads all the time its fine gives it it a facebooks feel. Dont worry about it.

AC cars have two fans so it's a bit confusing I guess when you only have one.

I would look into changing the relay next it should be available. There is a control box under the passenger seat. If thats messed up it is hard to find a relacement.

You may just have to rig up a switch make it run before your trip and run it your self.

No need to replace the relay, if jumping the thermosensor works then it should turn on, that is energizing the relay coil. Um, so what do you mean by its acting up? Are you sure you are reaching temp? It kicks on at like 195F, I should know because my car can barely reach that temp and before I knew that I lived in fear of overheating.

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Originally Posted by ShiRen

No need to replace the relay, if jumping the thermosensor works then it should turn on, that is energizing the relay coil. Um, so what do you mean by its acting up? Are you sure you are reaching temp? It kicks on at like 195F, I should know because my car can barely reach that temp and before I knew that I lived in fear of overheating.

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yeh confuses me too, the first never seemed to kick in, the replacement was fitted, and while I was idling the car a few weeks back, the temperature climbed and climbed high on the dial but the fan didnt want to turn on. High enough and hot enough that when I panic turned off the ignition, about 3/4 litre of coolant seeped out the overflow with a nice fizzy sound. No the end of the world, but assumed it would turn on before it got decently hot.

Coolant is getting to the sensor right?
You can test the switch in a pot of boiling water too, just don't scald yourself. It will switch from open to closed like a mechanical switch once it reaches temp, you can see it on a multimeter