bleeding/venting the cooling system

[soxnail]

I do realize this topic has been beat to death......but I am having no success in doing it this time. Normally the front end higher than the back and filling the system let the air out of the vent. Drive and repeat a few times and it works.
In this case after replacing the water pump, both the thermostats, hoses and the heater valve (it was leaking). I also flushed the heater core both direction, confirmed the operation of the heater valve.
500 miles of front end higher and venting (both hot and cold engine), The car is running hotter and there is no heat out of the hvac. So air pockets right ?
One more data point the temperature gauge does not the fluctuate just climbs to the second white line. I am used to seeing it at the first white line.
The only difference in the lay out is that I moved the heater valve up so it was easier to see and get to. It is still below the vent point.
I have also tried the "using a pressure tester to fill the system" same results.
I am about to try the vacuum the system the system and then fill it with the vacuum drawing the coolant in.
Any insights would be appreciated.
Thanks Sox

[grendiers]

How about using a coolant pressure tester with vent open?

[944 Ecology]

After doing major work on the cooling system, I would carry a 12 mm box end wrench around with me (for a couple of weeks) and open the bleed screw. It seemed to work well as the air in the system found its way to the highest point.

[soxnail]

Originally Posted by grendiers

How about using a coolant pressure tester with vent open?

Sox: "I have also tried the "using a pressure tester to fill the system" same results."

Thx

[soxnail]

Originally Posted by 944 Ecology

After doing major work on the cooling system, I would carry a 12 mm box end wrench around with me (for a couple of weeks) and open the bleed screw. It seemed to work well as the air in the system found its way to the highest point.

That is what I have been doing for the last 1200 miles....Only coolant comes out.
Sox

[soxnail]

Used a vacuum fill system (home made), that fixed the running hot issue.
The no heat issue was due to the heater valve being too high as compared to the engine block, even though it was below the vent hole height.
Sox

[soxnail]

Well premature...
Fixed the no heat issue but the running hot still exists. One interesting thing is that the slow fans have always come on at the first white mark on the gauge. Now they are coming on later, see attached pic.
At this time the only item that is original in the cooling system is the radiator.
I did get a very small "pisst" of steam from the vent after the run, so I will keep venting.
Sox

[soxnail]

The gauge in the dash tests good....Interestingly it is fed from unregulated +12v, so if the the car's electrical load changes, lights on for example will cause it to read high.
Still looking Sox.

[soxnail]

One more theory put to bed...
I thought that the old thermostat might have been a 'cold' one, but nope it's 80 Deg C. so the car was running cooler before I did all the cooling system work.
Sox

[BobCT]

I’ve been chasing a similar issue on mine. I would strongly recommend the $80 Maddox vac bleeder from HF. THEN you can completely rule out a bleeding issue which I must have done 20 times.

[soxnail]

Originally Posted by BobCT

I’ve been chasing a similar issue on mine. I would strongly recommend the $80 Maddox vac bleeder from HF. THEN you can completely rule out a bleeding issue which I must have done 20 times.

Sox: "Used a vacuum fill system (home made),"
I already did that, vacuumed to 25 inches and let it suck in the coolant. Interestingly when it was done (no more vacuum) the coolant level came to exactly half way between the max and min line.
Sox

[soxnail]

Further... tested the instrument cluster gauge, it is mostly accurate. Tad high at 115 deg C, but dead on between 100 and 60 Deg C.
Sox

[soxnail]

Slightly different question, I pulled the water temp sensor to do a bench test on it (not conclusive, but definitely of at 212 boiling point).
My question is : when I pulled the sensor out no coolant came out, I could see see it sitting right at the rim of the sensor mount hole but since this point is lower than the vent hole should there not be some coolant coming out of the sensor hole?
Thx Sox

[nize]

i used to have this same problem for years and finally installed the lindsey steam vent hose and the problem went away.

one issue is that a pocket of air gets trapped at the very back of the engine head by the firewall which can never be removed, and the kit returns that air back to the coolant reservoir.

it requires drilling a hole in the engine head and the best way is to remove the head to do this right. the kit is here:
https://www.lindseyracing.com/LR/Parts/STEAMVENT.html

[soxnail]

Looks like that is what I may need....
I just did the head a couple of years ago and about 30k miles, so I really don't want to rip back into it. There has to be another way of getting rid of the air pocket. Obviously flush and re-fill have been done on these cars since 86'.
Sox

[soxnail]

Originally Posted by soxnail

Slightly different question, I pulled the water temp sensor to do a bench test on it (not conclusive, but definitely of at 212 boiling point).
My question is : when I pulled the sensor out no coolant came out, I could see see it sitting right at the rim of the sensor mount hole but since this point is lower than the vent hole should there not be some coolant coming out of the sensor hole?
Thx Sox

Been traveling so a little time off.
I think I need to address the issue stated above. If no coolant comes out of the temp sender hole then the level must be low correct ? But I cannot put more coolant in without it just coming out of the bleed hole.
As far as I can tell the sender hole is below the bleed hole so how is this possible ?
Need some one way smarter then me to answer this.
Thx Sox

[nize]

i'm assuming you're doing this with the engine cold so the thermostat is closed which will affect the coolant path.

also, have you tried venting the system by opening the coolant reservoir cap?

[soxnail]

Nize yes and yes.

What I am trying to figure out is if the vent point is higher than the sensor why does the coolant come out of the vent but not the sensor hole ?
Thx Sox

[nize]

are you talking about the coolant temperature sensor on top of the engine? if so, it's probably because that's the low pressure area (due to the water pump/coolant return path) so if you open that with the engine running it will suck in air.

the vent point is a high pressure area (on the other side of the water pump).

i'll bet if you open the sensor with a hot engine turned off, coolant will blow out.

[nize]