Yeah, Compnine shows a build date of 10/12/93 for a VIN of 118955.

I’ve spent almost every free minute thinking about the cooling situation. I took a laser temp to various parts, and the heads would be showing upwards of 300 degrees while I didn’t feel any liquid in the WP return hose, and the WP showed like 100 degrees. Having the bleeder screws open didn’t change anything. I think I introduced two massive air pockets when I put the new heads on. At least that is my hope.

 

I have not been able to get the engine drain plugs out, but I did my best with a coolant drain and refill anyway. Got the car level, flushed out the heater core with distilled water. Checked good operation of the thermostat on the stove, and bumped the engine over and saw that the fins on the water pump did turn. Filled through the thermostat until it wouldn't take any more, then filled the radiator to the brim and then some with a gravity funnel. Steady fluid was coming out of both bleeder valves.

The first startup of the day was very promising. While it did eventually hit a point that I was uncomfortable, it took quite a bit longer. Another couple startups a few hours apart from all unfortunately made the needle peg. It's hard to believe I would still have air pockets. The only thing that I found a little off about my fill kit was that I could not get a good air-tight connection to the radiator cap, I had to insert one of the fittings down a bit (under the overflow hose) to not get it to gush outside the fill. The WP neck gets hot, the radiator to WP hose gets hot, the return from the heater core is hotter. The fluid near the top of the radiator is basically room temp. It's not making a loop.

I'm at a bit of a loss. There's still some nasty fluid from the block/core that has turned everything brown, I had a thought of maybe setting up my own flush contraption, just a constant flow of distilled water from the cap and out into a bucket from the WP coupler until things start looking clearer. Let the engine help me cycle everything.

Edit: manual fans on, this is my kit from Amazon:
Have not put a 160 in yet. Think I'm going to order tonight.

Edit 2: Realized I had the flow circle incorrect in my head, edited my wording. I'm not sure why the WP supply hose from the radiator would be getting hot, but not the actual fluid in the radiator. Will also put a computer on the PCM tomorrow to check WP temps.

 

Perhaps a restriction in the radiator?

 

I did have that thought. Going to flush water from the fill through to the WP return inlet today.

 

You don't need to use distilled water for flushing, "Hard" tap water only becomes a problem if it's left in the system for extended periods of time.

 

Either I have another blown head gasket or the block is compromised. It was a good run, but the project is shut down.

 

Before I go installing a new bottom end, I wanted to try and get as much coolant out as I can, and refill with just water. I have been reading that some people use a vac blower to cycle all the water out of the block without having to take out the drain plug and knock sensor. Here is someone doing it on a 95 Corvette.

https://www.corvetteforum.com/forums...ush-works.html

I was thinking about this on my car, and wondering how the air would force water out of the block if it can go straight back to the radiator or out another disconnected hose. I'm holding out hope that when I put in the 160T, it finally opened up and got some of the previously contaminated coolant out of the block finally and it surfaced in the radiator. It's a long shot, but I'm willing to try it. I'm also paranoid about rounding or breaking the drains, so I want to save that as a last resort.

 

I ended up pulling the drain plug on the driver side, but it did feel like I was heading towards breaking the knock sensor. So mostly drained, and filled back up with hose water temporarily.

So here’s the thing: can the temp sensor in the head function, but be inaccurate? The gauge is pinned past the redline, but it seems to run fine (albeit high) and putting a laser on the outside of the head shows a variance of temps. At the front of the head it can show low 100s. Nearer where the sensor is, mid-high 100s. Near the exhaust on 3/5, mid-300s. The top of the intake will show maybe 100 degrees, and is not very hot to the touch. I idled it like this for almost ten minutes without much of an issue. I plan to get WP temp tomorrow with the laptop, but the WP thermostat outlet was fairly low temp. Low 100s. I thought about maybe running it with a thermostat as an experiment.

But, eight weeks after I bought it and parked it at my MIL’s, was comfortable enough with how it was running to drive it home.

 

Sure…. Low sensor resistance = high temperature reading. Could be a direct short in the wiring or sensor. Easy to test reference voltage and sensor resistance vs. temperature.

On the other hand an air or vapor bubble at the sensor can produce actual hot spots. The steam line is supposed to eliminate bubbles. Is it hooked up?

TEST PROCEDURE:

4th Gen LT1 F-body Tech Articles

 

Yes, once you pointed it out I hooked the steam pipe back up how it was supposed to be. Outside of EGR delete, all lines should be hooked up as it came from the factory.

I did do the resistance test previously, and with the sensor in the block it seemed to test ok. But perhaps I’ll do another test with it out of the block.

Still early days, lots of things left to fine tune. If there is still an air bubble I’m not sure what else I can do to prevent it. Filled at the thermostat, filled at the radiator with vent screws open, good output through the screws when I closed them. Good pressure with the new cap, filled on a slight incline with the nose up.

 

I drove around the block for the first time just now. Temp gauge started to rise, and I turned the A/C on. Dropped to the floor. Then about fifteen seconds later was pegged to the ceiling. Intake manifold was barely warm when I got back.

Meanwhile, the brake pedal is only a suggestion, and the idle is stupidly high. Some things to work on before it goes back out.

 

Did I miss it or have you monitored engine temp with a scanner? Your temp gauge circuit seems to have issues.

 

That's next up before it goes back out again. Was monitoring surface temps with a laser thermometer.

 

It's an infra-red device. The "laser" is just an aiming feature. You need to understand the limitations of the device. Remember that the surface of an item (engine block, or radiator hose) does not necessarily represent the temperature on the fluid inside (coolant), depending heavily on the insulating properties of the intermediate structure.

That device is very sensitive to the finish of the object you are measuring. Bright, reflective surfaces throw it off. Dull, flat surfaces produce more accurate results.

It is very sensitive to distance from the object you are measuring because it affects the diameter of the area you are measuring.

Cautions from Fluke:

 

I would buy a mechanical temperature gauge and use it, then you eliminate any faulty temperature sensors, bad grounds, bad wiring etc!!!