Coolant change now no heat - PeachParts Mercedes-Benz Forum

fruitcakesa · #1 03-13-2009, 10:40 PM

This cooling system thing continues.
I went to the "big city" Napa and got some Zerex G-05 at $17+ /gal
and hustled home to get the deed done
I managed to get about 8.5 qts down the top rad hose before it started weeping out the top hose neck on the expansion tank.
The car is up on jack stands sothe nose is higher than the tail.
I started the car and after about 10 minutes the temp gauge was at 84C
but I have no heat in the cab.
The heater functioned before the change so I assume the core is ok.
If it is trapped air , how best to purge it out?

kerry · #2 03-13-2009, 10:51 PM

Do you have the heat on high while running it on the jackstands?

::matthew · #3 03-13-2009, 10:56 PM

Quote:

Originally Posted by fruitcakesa

I managed to get about 8.5 qts down the top rad hose before it started weeping out the top hose neck on the expansion tank.

your 240 has an expansion tank?

weeping doesn't sound good.

run it with the heater on and with the cap off...this has helped me burp mine. after it's running awhile, try to add more to the top rad. hose.

fruitcakesa · #4 03-14-2009, 07:52 AM

I am calling the top tank on the rad the expansion tank and weeping is the wrong word.. I meant that eventually filling thru the top hose raised the level in the rad till it began to run out the top hose neck on the rad since it is open while I pour the coolant into the unconnected hose.
I had the cap on loosely and the heat full on while I was running the engine.

t walgamuth · #5 03-14-2009, 08:22 AM

I usually just take the car and drive it for a while to get it good and warm so that the tstat opens and circulates coolant, then refill. Repeat as necessary.

Its not rocket science, really.

fruitcakesa · #6 03-14-2009, 08:42 AM

I would love to take it out for a drive but unfortunately the car is still in the process of recon and not at all ready to hit the road. I guess I will fire it up again in the shop [with the outside exhaust hose hooked up] and see if it clears up.

fruitcakesa · #7 03-14-2009, 10:37 AM

Ran the car again till 84C on the gauge still no heat .
The small hose from the rear of the block to the heater core neck on the firewall is hot but the small hose from the engine to the heater valve and the lower rad hose are cold.
New thermostat is correctly installed as I put it in like the old one came out.
If the tstat is faulty, ie: stuck shut, would that keep the lower hose cold and would the temp gauge register normal temp?

kerry · #8 03-14-2009, 11:26 AM

Are you sure your heater valve is working right? (ie opening up) Lower hose should be colder than upper hose.

fruitcakesa · #9 03-14-2009, 11:33 AM

Well, the levers on the outside of the valve operate smoothly.
How else could I tell if it is functioning properly?
I put the new and old tstats in water and brought them up to temp 80*C and both opened and then closed when cooled down

cdplayer · #10 03-14-2009, 12:14 PM

I read somewhere here a member had a similar problem and was told to open up the small inlet/outlet hoses at the firewall mounted mono valve. Now your car does not have a mono valve, but I thought this theory of opening up the connecting hoses at your firewall mounted heater valve would give you the same result.

fruitcakesa · #11 03-14-2009, 01:26 PM

Great minds think alike?
I pulled the the outer hose from its heater valve neck and discovered a dry valve and hose. Same for the other side.
Poured coolant via funnel until the level in the rad began to rise.
This totally filled the smaller inner hose but left all of the outer hose empty.
Started the car and got immediate heat from the pass side which is controlled by the smaller inner hose [the right valve side when facing the car]
No heat from the other side.
I pulled off the outer hose again; it was still dry and tried adding more coolant but it just raised the rad level.
Hooked it up, restarted the car and fiddled and squeezed all the hoses to try and move the air bubble out.
Finally got some warm air out of the drivers vent and somewhat hotter air from the pass side. Ran it a few minutes more but the heat did not get any hotter so I figure there is still some air in the line.
It needs a good drive to work things out.
But the wheels are off so I am going to replace my rubber brake lines then I can button it up and wait till a hard freeze or the winter and mud weather to be done before I take it out into the world.