924Board.org

charly · Joined: 17 May 2012 Posts: 13 Location: Virginia

Hello!

I could use some new ideas concerning the cooling system on my '79 N/A...

After getting progressively warmer at idle and city driving over the past few months, I decided to go through the cooling system.

-drained system and flushed (hot) 4 or 5 times with (distilled) water and a cleaner of some sort for the heck of it. heat valve open. nothing too nasty came out.

tried to bleed system after, but no coolant from bleed hole. hose from thermo housing to rad is bone dry.

-replaced thermostat with confirmed good one (old one confirmed good, too). still dry.

- replaced water pump with meyle from autohausaz, as well as a few old hoses. refilled to max and let set overnight.

morning, tried to bleed system, but only small amount coolant can be seen if i look down into the line from thermo, but it's not gushing forth like it should. I let it run 15 min or so and the gauge gets a bit past 1/2 mark, i see no leaks anywhere and fans are working as advertised. the radiator feels warm after this time, but not hot. hose going into pump is hot.

my thoughts go to the radiator being blocked, or the new pump is not working??

I can't quite figure it out. anything come to mind?

Charly

Tanso · Joined: 16 Mar 2014 Posts: 81 Location: Sweden

Blown head gasket maybe?
_________________
Our 1983 Porsche 924 project: http://www.924board.org/viewtopic.php?p=364034#364034

charly · Joined: 17 May 2012 Posts: 13 Location: Virginia

thanks for your response, i've considered that one, of course! but have been avoiding it. Soon may be time to take the plunge and do the foes anyway.

even so, i'd like to understand what exactly is going on here. i don't have any other head gasket symptoms like white smoke, loss of coolant, contamination of oil and coolant, plugs look fine. I haven't done a compression test yet, however.

it definitely seems to be a problem that the coolant isn't making it past the thermostat with the volume it should, head gasket blown or not.

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

does the thermostat have a small hole drilled in it to allow air to bleed past?

If not, add one with a very small drill bit and it should work better for you.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

charly · Joined: 17 May 2012 Posts: 13 Location: Virginia

yep, it does. i put in a standard wahler one. you can hear the little air valve clinking around when you squeeze the lower rad hose without the engine running, i guess letting some fluid pass.

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Sure your pump is working?

in the past, I've filled the upper hose from the bleed nipple using a small funnel to help get the cooling system filled.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

charly · Joined: 17 May 2012 Posts: 13 Location: Virginia

not positive the pump is working, but this is its maiden voyage. do they fail right of the bat very often?

was just discussing filling the radiator up from the bleed valve with a friend, i don't fully understand why this would help (assuming the radiator is blocked?). by filling the radiator by the expansion tank, this should be the quickest way to supply coolant to the pump. as it enters the radiator just above the hose to the pump.

also, the level in the exp. tank has not been falling or rising as i attempt bleeding, so the pump hasn't been taking water from the radiator/expansion tank supply.