Hi Everyone,

I have a Japanese market 4WD 1994 Civic RTSi with the DOHC ZC motor. I am resurrecting the car here in New Zealand and I've run in to an overheating issue:

Symptoms:

• Lower rad hose remains cool
• No heat in cabin
• Cooling fan won't turn on
• Overheats at idle

Troubleshooting done:

• All bleeding done according to service manual
• All hoses checked for blockages, none found
• System flushed
• Thermostat replaced, tested and working before install, old one didn't close completely
• Fan thermoswitch tested and working
• Fan relay works
• Fan works when jumped
• Heater core bypassed, no difference
• Near-new good condition rad

Things to know:

• New Zealanders are terrible for using straight water for cooling, so I assume this was used for most of its life
• Unknown age/condition of water pump, but timing belt looks really fresh, so it was possibly changed at the same time as this (unknown though...)
• Engine was removed from a vehicle that was in a minor wreck (damaged roof) but may have been sitting for a couple of years
• New oil put in recently, no contamination found in old oil nor when checking new oil

Am beginning to suspect a bad water pump ... but wondering if there's other things I've missed to diagnose the problem. Any way to test the water pump without removing it first?

 

You might consider flushing the cooling system and heater core. The cooling system may be filled with rust and mineral.

 

Water pump n is a mechanical gear that is manually spun by the timing belt. You'll have to tear into it and inspect. Thermostat is probably clogged.

 

Right... So I should add, system was flushed. And I stated the thermostat was replaced already.

Pump impeller may have separated from shaft??

 

probably..or corroded. Heater core is probably clogged to *****. What you can do is disconnect the heater hoses from the engine and run a hose through it to verify proper flow. Connect the water hose to both inlet and outlet to verify if any build up comes out.

i want pics of this beast.

 

Heater core and whole system was flushed. A water hose was jammed in to various rad hoses and sprayed until the water ran clear.

As for pics ... sure, here's a couple of quick shots.







deschlong's 94 Civic RTSi - Front<br/>ZC DOHC motor





deschlong's 94 Civic RTSi - Interior





deschlong's 94 Civic RTSi - Rear





deschlong's 94 Civic RTSi - Rear differential





deschlong's 94 Civic RTSi - Front propeller shaft

 

wow, an rti....

anyways, something else you can check is if that valve opens and closes.

 

/end thread





Looks OK from here.





Crigey.

 

Wow. Poster child for coolant.

 

This is why you don't use straight water. I hope all the rust particles were flushed out or else you'll have more issues.

 

These guys are terrible for it here. Coming from a cold climate, I was dumbfounded. They even have watering cans at petrol stations so you can "top up" your rad. Crazy.

 

That's pretty astounding. At least you get all the cool vehicles, though. Hopefully replacing that water pump solves your problems.

 

When you get a chance, take a look at the heater core. I know its a bitch to get to but I don't want you having any overheating issues if fluid isn't flowing properly.

 

Thankfully the motor is not the original from the car. It is a replacement one I pulled myself from a wrecker yard JDM EG5. So the rust and **** collected in that other poor bugger's car which has now firmly departed this life and entered Honda heaven.

 

All gravy. I just didn't want that stuff still cycling through your system.