Bare minimum, it should absolutely tell you if the CAT is plugged or take the CAT issue out of the equation.

A diagnosis win regardless.

 

I think you've got far too much coolant in there. Check it when cold & siphon off the excess. There should only be one inch or so in there - between the MIN & MAX lines.

 

Yeah I think I may pull some out yet. But the level goes up and down more than what is normal with temperature change

 

How do you know what is "normal" if you don't have the level down to an acceptable level when cold?

 

I’m a mechanic

 

Glad to know that!

 

Yup! We just don’t know everything unfortunately. And some things can be properly confusing. This car did have some questionable service history before I got it which is why the oil rings are bad

 

Well, I've been turning wrenches on cars since 1954 and I don't know everything either!

 

Well, it may be a minute till I work on it again!

 

Got the cat out and drove it around and the header is still glowing. I didn’t drive it long enough to get in multiple driving styles, so I don’t know if it is less than before

 

Another thing I thought of, the oxygen sensor is bad so the computer is probably in a preset fuel mixture. Since it has a 17% pulley and a larger cam, is that increase in airflow making it lean? Since it doesn’t have a MAF sensor it’s probably not seeing the airflow increase? I don’t know how much the MAP sensor can see an increase. Which makes me wonder, how good is it to keep running it like this? If it is in fact the second O2 sensor, would it make a difference if its still catless when replaced? It’s been a while since I’ve messed with emissions control on anything so I don’t remember exactly how the fuel mixture is monitored and adjusted. I also tried another coolant reservoir cap that I had laying around, that didn’t make a difference but I also don’t know if this cap is any different

 

So I’ve gotten a new reservoir cap on a bit ago and so far it hasn’t barfed out coolant. But I’m still getting a decent amount of air out of the bleed valve every run cycle. Even if I let the air out after its fully warmed up, run the crap out of it, and check it again, I’ll still get roughly the same amount of air out again. And for the fuel mixture question, I have fixed/verified my knowledge that the afr is controlled by the front sensor and my bad one is the rear sensor. So that shouldn’t be my problem there. Possibly a vacuum leak somewhere that I haven’t found yet

 

I am planning to rebuild the engine sometime soon since the piston rings are shot. Do I just replace the rings? Or do I do a full rebuild pistons and rods? Would there be a benefit? I don’t have any plans currently of tuning it or adding more power than it already has, but I would like to start tracking it sometime

 

Right, little update here. Engine is rebuilt, and it literally had no affect on the cooling characteristics. I been driving it around now couple thousand miles hitting the bleed valve often to let the air out. But now I really want to get this sorted out. Not concerned about the glowing header anymore, it needs to be tuned for the mods I did. I have dug around some recently with the cooling and found out if I let it idle until it fully warms up, no air comes out of the bleed valve. But if I drive it, it does. Every drive cycle. Seems to have something to do with pump speed? I did a leak down test with 100psi in all cylinders on a stone cold engine and no pressure seemed to appear in the cooling. But that doesn't say there isnt a crack/hole towards the bottom of the cylinders as the pistons have to be at the top for the test. Thats one theory. Other theory is the thermostat I installed could be defective in that it doesnt close all the way making it warm up slower (warms up faster sitting still) and maybe is restricting flow making pressure build up enough at the reservior making the cap dump pressure at high rpms and causing enough vacuum on the other side of it to suck air in. Is that possible? Any thoughts? I been so puzzled by this. And yes I did crack the bleed valve by the thermostat. I have pulled the thermostat and inspected it and it looks ok visually. I heard about the Volvo coolant tank fits and holds more pressure and since we got a junkyard full of them I'll try one of those

 

The Volvo coolant tank cap is installed, and so far it is holding pressure good. My next idea of things to try since the time I let it idle no air came from the bleed valve, is to start it and just let it idle repeatedly over the course of a couple days to mimic the drive cycles just without higher engine speeds.

 

I ran it a couple weeks with no thermostat and 3/4 air blocked to the radiator. No air ever came out the bleed valve. Ordered a new thermostat and that fixed the warming up issue but I'm getting air out of it again. The first thermostat was a Rein and has a black seal, the last one I got was a genuine Mini with a white seal. Both say MotoRad, the white seal is just a hair thicker, the top crimp is slightly different, and the spring tension is tighter on the Mini thermostat which I'm sure that is the reason the first one took longer to warm up. The air that is getting into the system is not from the engine from like say a crack or head gasket or I would have still got air from the bleed valve when I had the thermostat out