Looking good. I read through parts of the thread again and had some questions.

I noticed you said your coolant is brown. Have you done a complete flush and burp/bleed of the system. (I read where you just bled it, but just double checking?)

Also, fans not coming on is an issue. Shoebox has a good write up for fan and fan relay operation. I wonder if they were wired to manually control them at full speed via switch for some reason.

I've burped my system recently, thinking I got all the air out, and then did it again, and was surprised to get more air. I've drained my radiator twice (removed and replaced intake manifold gaskets, and installed oil cooler bypass hose).

When I drained the system is was green both times fortunately with no particulates/rust etc.

 

Hi Eric. I did a complete flush of the system, including removing the knock sensor and the plug on the driver's side and flushing until the water was clear. I installed an in-line coolant filter to catch any crap that might still be in the system. I want to run the engine, maybe even put some miles on the car and then drain and fill with 50/50. Right now I just have distilled water in the system.

I used a special tool to refill the system. It pulls a vacuum and then sucks from a bucket to fill it. It's supposed to remove all the air and then replace it with exactly the right amount of coolant. Main benefit is, supposedly, no need to burp the system. I did notice today that the coolant level in the radiator was below the level sensor in the radiator, so I added some more water to top it off.

I ran the car a few minutes ago with the AC on to see if that forced the fans on. It did not. While the engine was running, I jiggled the fusible links near the battery because I read online about trying that to see if it might enable them. I understand they go bad commonly. Doing that had no effect.

Time to do the diagnostics on the shbox site. I have a multimeter and even a Power Probe, though I'm not really very good at using them.

I'm nearly positive I heard the fans running back when I started this project, so it's odd that they just aren't working now. But, maybe I am wrong and they weren't running before.

 

Using the info on the shbox site, I jumped pins #5 and 6 on the diagnostic port, then turned the key to "Run." Both fans came on. According to him, that means all the relays and wiring should be okay and the PCM is capable of operating the fans. Not sure what to do next.

"You can jumper two pins on the DLC that should cause the fans to come on. 1993-1994 cars with the 12 pin DLC can jumper pins A and B. On a 1993, that is the same way that you would retrieve trouble codes from the ecm. The 1994 won't give you any codes, but the fans will engage. 1995-1997 uses pins 5 and 6 on the 16 pin DLC to initiate what is called "field service enable mode". That will cause the fans to come on and operate most sensors for sanity checking. After placing the jumper on the correct pins, turn the key to ON (don't start). If the fans work after jumpering the DLC, your PCM is capable of operating the fans and all fan wiring/relays should be ok."

 

With your scan tool showing real time data, start the engine with coolant temp below 200°F. When the coolant reaches 226° FC1 should switch to ON, and both fans should come on at low speed. FC2 won’t show ON until coolant reaches 235°, and fans should shift to high speed.

Maybe the dash rocker was for the fans. If it's wired correctly it won’t set codes. The PCM diagnostic system only monitors the signal side of the fan relays. It can’t tell if the fans are actually running.

The electrical section of Shoebox has the manual fan switch info, showing where the switch wires would tie in, and schematics.

 

I just idled the car for a while with the Actron showing the datastream. The results today are different from yesterday.

At a bit more that 226 degrees, the FC1 Relay went from off to on. I visually confirmed that the fan on the driver's side was spinning.

At a higher temp that I could not precisely observe because I was moving around, the FC2 relay also switched to on. I can't visually see the PS fan moving because of the alternator and other things blocking my line of sight even if I lean into the engine bay.

The scanner did not show the coolant temp drop after the fans came on. At 252 degrees, I shut the engine off. Should the temp be dropping with the fans? How hot should the coolant be getting? This is straight distilled water right now.

The temp gauge in the dash was in the red zone when the Actron was only showing a coolant temp of 180 degrees. I don't have much trust in the dash gauges. The fuel gauge shows well above full, for example, but I only just added six gallons after the car turned out to be so empty that it would not start, despite the gauge showing 1/4 tank. Is it possible for the dash temp gauge to be accurately showing a much higher coolant temp than the gauge in the water pump? With the dash temp gauge, is it either going to be dead and not working at all or working and accurate, or is there an in between option where it is working but inaccurate?

 

Do not let it get that hot. Both fans should come on. The low speed should be adequate to pull the temp down from 226-deg. If for some reason it reaches 235-deg, both fans should shift to high speed and should easily prevent the temp from rising any more, should drop fairly quickly. A healthy cooling system should idle at the mid-point of the gauge (~210-degF) or lower. The PCM is responding correctly. The cooling system isn't.

 

The radiator, heater core, t-stat are new. The system was thoroughly flushed. If I have a coolant flow issue, am I correct that it will be an issue with the water pump (not new, corroded, but spun by hand when off the car) or the thermostat? Or...an air bubble, which would be frustrating given that I used that special tool to pull a vacuum and then suck in coolant in its place.

 

Have you checked the front of the radiator for a plastic bag or other obstruction? Not likely with the radiator being replaced, but worth a check.

Are BOTH fans working? Are the fans rotating in the correct direction - pulling cool air through the radiator, not trying to push hot engine compartment air outwards through the radiator?

Is the coolant water pump suction hose possibly collapsing?

What was the condition of the splined driveshaft for the water pump?

In a post above you indicated the radiator coolant level was below the level switch. That's a huge red flag. Where did that coolant go? After adding water, did you bleed the system?

Water actually has a higher heat removal capacity than a 50/50 coolant/water mix. That should be helping the system perform more efficiently.

I'll go back and read through all the posts to see what we may have missed.

 

You're basically a hero for sticking with a hack like me on this project. Thank you.

When I removed the radiator cap about twenty minutes ago, once everything had cooled, the water level is AGAIN below the level of the level sensor. Where it's going is a mystery to me given the fact that I used a tool that supposed to have pulled all the air out of the system! I did crack both bleeders while the engine was running earlier. I got air from both, but not a vast amount of air.

I will check the front of the rad for an obstruction.

I will run the car tonight and check for any collapsed hoses.

How can I check the see what direction the fans are moving the air without getting my body close to hot or spinning objects?

I thought that I had taken some pics of the water pump when it was out, but I can't find them to check the condition of the splines. I do not recall seeing any damage to them, but memory is a flawed instrument.

 

The steam pipes are present. The one of the passenger side has a metal tube that comes up on top of the intake, then enters a rubber line that goes into the bottom of the throttle body.

I used a flashlight to look at the front side of the radiator; no obstructions.

I looked at the rubber hoses; I didn't see any that looked collapsed.

Lemme ask another basic question: if you start a car with the radiator cap off and watch it until the thermostat opens, what are you supposed to see? I did this to see if I could observe some evidence of water "flowing" in the system, whatever that looks like.

I had burbling and the coolant rising up and down, gradually at first. It started spilling over the radiator neck. At some point, the water got hot enough that I could see steam coming off of it. It was spilling more aggressively at that point. I saw some bubbles. I opened the bleeders a few times, when the engine was cold and when it got hotter. I didn't get any strong streams of water; it looked like water was flowing out of the t-stat bleeder and from the heater hose bleeder it seemed more like sputtering. I couldn't really concentrate because my garage floor was getting dumped with coolant and I wasn't really confident in just letting the car run with the cap off and making this big mess. I didn't see what looked like any "flow" of the water visible in the filler neck, but I don't know what it really should look like.

I put the radiator cap back on and got in the seat. I could see the Actron was showing water temp just under 200 degrees at that point. I waited to see what would happen. FC Relay 1 came on around 227 degrees and FC Relay 2 at 230-something. I was frazzled. I didn't want to stick my hand near things to see if I could tell which way the fans were moving air.

 

There's only one steam pipe. Starts at the back of the driver side head, picks up the connection at the back of the passenger side head, wraps around and runs forward. On a 93/94 it has a rubber hose that connects directly to the radiator, below the fill neck. On 95-97 a rubber elbow connects the steam pipe ro the throttle body, as yours does. The hose coming out of the throttle body on the driver side then runs over to the connection on the radiator.

Shoebox has factory manual diagrams, marked to show the flow directions (I may have linked these before).

http://shbox.com/1/95-97_hoses.jpg

http://shbox.com/1/heater_hoses.jpg

Because you are running straight water (no coolant), and you have the radiator cap off (no pressure on cooling system), the water will start to boil as soon as it reaches 212°F. Adding coolant to the mix not only lowers the freeze point, it elevates the boiling temperature. Adding pressure to the system (factory cap is 18 PSI) raises the boiling temperature even higher.

The water can actually start boiling sooner in the water pump suction line, because the pressure there is negative (PSIg). Cavitation in the pump can make the situation worse, but that's more likely to happen at very high flow.

So.... it’s likely virtually everything you describe is the result of the water boiling. The scary part of where is the water going = possible blown head gasket.

 

Is the possible boiling casing the surging that I see at the open filler neck, then?

Somewhere in this thread, I think I have some pics and description from the pressure test I did on the cooling system, I think before I installed the new radiator. I had been trying to determine if there was a blown head gasket. According to that test, it didn't look like I did. The pressure tester maintained pressure and did not leak down, as I recall. I'll go back in the thread and see what I described.

 

Back in July, before doing the flush and changing out the radiator, I bought a pressure test kit. After running the engine for seven minutes, my gauge read about 7psi, which I was told at the time meant combustion gases were not entering the cooling system.

 

I am not familiar with that test procedure.

Boiling water explains everything you described in post #70.

Another possibility is the water is dumping into the reservoir as the system heats up (as it is supposed to), but when the system cools down the vacuum that develops in the radiator is not pulling the water back into the radiator to keep it full. That only happens with the cap on.

Is the reservoir filling up?

 

If you aren't familiar with a procedure, that doesn't give me much confidence in the procedure! Maybe I should consider compression and leakdown tests to check for head gasket/cracked head issues another way?

The overflow reservoir was not very full when I checked it yesterday. The level appeared to be lower on the dipstick, but I didn't ascertain it precisely.