1983 280zx turbo engine

[Zed Head]

How about pressurizing the cooling system and waiting to see which cylinder fills with coolant.  Watched a youtube video where the guy forgot and left his pressurized overnight.  The leak area was apparent.

[Dave WM]

1st off tic is gone, pulled the pivot, reassembled under oil bath, all good.

Now the odd stuff. installed T stat, put funnel in rad, made sure it was the high point, filled to the max, no instant overflow. as the engine heated up I got a slow expansion and push out of coolant but no bubbles. by the time it hit about 185f it was just a bit of water coming out. Not sure I understand how that could happen unless there is gas filling somewhere, but decided to do the chem test again, before draining coolant (with it still running) I just pulled some garage air thur the test kit, opps blue is starting to turn green....

So before ANY more messing the engine is going out to the sidewalk for the next test. I cant imagine that enough exhaust gases were accumulating inside an open garage, but before any more moves, its going WAY out in the open air. Perhaps some of my recent decisions may be explained by the garage air test.........

ZH I will add that to the list of to do IF i get another L after an OUTDOOR test of the chem test.

 

[kickstand80]

3 hours ago, Dave WM said:

but decided to do the chem test again, before draining coolant (with it still running) I just pulled some garage air thur the test kit, opps blue is starting to turn green....

Interesting observation. I wonder how may blown head gasket have been replaced due to too much exhaust gas in the garage!  

[kickstand80]

Have you ever used one of these?

https://www.amazon.com/LEIMO-Cylinder-Compression-Leakdown-Diagnostics/dp/B07W9FXKTF

Everyone can use more tools!

[Dave WM]

leak down test done, passed with ony about 5-8% max loss. I suspect the combustion pressures are way higher so doubt I could pick up on a small leak.

I am going to try the top off with water test again. seems like NO water should flow out of the rad top on a cold start for at least a few min. IF any comes out at all then it seems must be gases displacing water. I figure it must be done cold to avoid any trapped air in the water jacket heating up. I assume IF no air at all in the water jacket, NOTHING should overflow as I dont think water expands from heat, at least until it shifts into steam. 

[Captain Obvious]

53 minutes ago, Dave WM said:

seems like NO water should flow out of the rad top on a cold start for at least a few min. IF any comes out at all then it seems must be gases displacing water.

I dont think water expands from heat, at least until it shifts into steam. 

Water does expand with the heat. Just not as much (volumetricly) as gasses do. So even if there isn't any air in the system, the water will expand as the system heats up. And that expansion will start as soon as the engine is started.

Now granted... If there is air trapped somewhere, or if you do manage to boil some of that water, it will expand orders of magnitude more than water. But even just the water will expand (even if it doesn't change state).

[Dave WM]

roger that CO. well I will have the videos soon, both of the water expansion and the chem test. Not looking good... let you guys have a look. tell me what you think.

will post here soon.

[Dave WM]

chem test

 

[Dave WM]

here is the water overflow test. Note I did the same test with my car that does NOT change the fluid color, and I had the same results, water started to over flow within the same time span as this video. So as CO mentioned, the water apparently was expanding enough to start flowing with out the introduction of gases (in my good engine in the car).

 

[Dave WM]

going to try adding some UV coolant dye to the rad, pump it up with a pressure tester, let it sit for a long while, then spin with plugs out and see if any dye is expelled thru plug holes. I tried already with pressure and then examine with borescope, but its not the best and could not really see well enough to call it. I figure the compression stroke will aerosol any accumulated coolant and spray will show the dye. I will spin the engine with the plugs out to hopefully disburse the dye, that may not do it though.

Edited August 5, 2022 by Dave WM

[Captain Obvious]

2 hours ago, Dave WM said:

I figure the compression stroke will aerosol any accumulated coolant and spray will show the dye. I will spin the engine with the plugs out to hopefully disburse the dye,

This sounds like another fantastic opportunity for you to film yourself doing something entertaining.

Pics or it didn't happen!!    

[Dave WM]

hmmm