Sorry me again, Cooling System =(

[Smokey Eddy]

Hey,

I posted a problem with my cooling before and it turned out to be a hose that leaked. Now i really don't know what's going on ( i never did in the first place )

symptoms:
gauge reads just at the top of the solid white 90% of the time. Other 10% it will read 1/4 temp for a short while and then return to the top of the solid white.
While at 1/4 temp the light (temp light) stops flashing. At the top of the solid strip the light flashes constantly.
A faint hiss from the expansion tank.


my horrible confusion on the matter:
my expansion tank and cap are new, why does it hiss?
why does the gauge read at all if it's a temp sensor that is broken?
why does it read so cold when the engine is clearly very warm (Very hard hoses after running)

possible info that may help:
new tank, new cap, new hoses but 2, straight water ATM not 50/50 coolant, i switched the two wires that go to the "T" at the head (coolant hose to the head) around a few times to see if the flashing would stop on my dash... they may be backwards? I just switched them again to day to see if it would make a difference.
While running and hot the expansion tank is empty. However, when cold it's inbetween the min and max lines... is this not backwards or does "expansion" mean something else in German?

my ideas:
maybe there is an air lock somewhere in the system?
faulty/crappy connections at the sensors?
Do i have to try and fill it with coolant/water while its hot and running? (open the cap, start it up and wait for it to get hot while adding coolant; just an idea?)

All advice is greatly appretiated.

[the caveman]

First off it doesn't hurt to fill the rad first, that way you know it'll be probably filled the the cold side of the thermstat. Then from cold, turn your heater fan off, but turn the heat volume slider knob to hot. Fill the system up. start it and while it's running squeeze all the hoses one by one,especially the heater hoses. Within a couple of minutes those heater hoses   should be getting warm, if so check by getting the car and check for warmth at defrost. turn the fan of again]. If they don't get warm, remove one [carefully !] and rev the motor a but until some coolant runs out, reconnect and check again for heat/defrost. Once that's done rev the motor a bit while squeezing those hoses. It takes a while until the thermostat opens ,but once all the hoses except the lower one get almost too hot to touch, it should then open. Keep the revs up until the rad fan comes on. If that all works as it should, you have a bigger problem.

[Smokey Eddy]

ok. thanks i'll do that!

[fatmobile]

How's the coolant flow into the resevoir?
 Steady?
 Spurts?

 Temp swings like that are rare.
 An empty, then full coolant resevoir is also rare.

[Smokey Eddy]

What do you mean by flow into the res. ?

if i undo the cap while it's under pressure but not hot anymore it'll gush up into the res. sometimes over flowing with velocity. but if i do it slowly in spurts and relieve the pressure the level comes up a little bit into the resevoir, like i said, between the lines.


I topped it up at a time before but it would leak out the excess through the over flow holes at the side of the tank.
I don't understand why this is happening. The rubber ring in the cap is fine. The Tank and the cap are SO new they can't be faulty. They worked fine at some point or another.

Should i just keep topping it up like it's belching out air locks or something?

I could be burninga bit of coolant but  would that cause this bizzare behavior?

[jtanguay]

sounds to me like you have a possible head gasket job coming up in the near future  

[Smokey Eddy]

i only just changed it.... Hence the straight water. Like .... 2 weeks ago?
my head has cracks between the valves. I'm waiting for the money to get a new 1.9 mtdi head from prothe.

[the caveman]

How is the flow from the small hose into the overflow ? How is the water pump. It's rare on the older style ones, but i have seen one or two with bad impellers. Did anyone recently dump any stop leak into it ? Any who it does sound like a HG or head mating problem.

[Smokey Eddy]

uhhhhh i THINK i know what you mean....
the waterpump is about 4 years old...

i just changed the HG with a 1.9 metal one. But the head is totally fubar so that's probably the hissing out of the expansion tank

but im mostly baffled why my gauge reads so strangely

[jimfoo]

I would not run straight water. The boiling point is quite a bit lower, and it has no anti-corrosion properties. It would be much easier for it to form steam pockets in the head, drastically increasing the chances for warping the head.

[Smokey Eddy]

ah, thanks! I planned to add some in there but i wasn't sure if i'd just have to drain it as soon as i got a reply as to what to do on here that req. me draining the coolant. I guess i could put it in something clean and reuse the coolant mix

[Smokey Eddy]

ok so my gauge reads really screwy.... Where is the sensor that gives the read out to the gauge? does anyone know? there are SO many wires going to the cooling in so many places im totally lost as to which one it is

[burn_your_money]

on the head. It's one of the 2 connectors on the front coolant flange. The other is the GP controller

[jtanguay]

I would not run straight water. The boiling point is quite a bit lower, and it has no anti-corrosion properties. It would be much easier for it to form steam pockets in the head, drastically increasing the chances for warping the head.

jimfoo makes a really good point... straight water should only be used in an emergency  :lol: even though the gauge might not read 100 dec C, there can still be hot pockets (yum!  :roll:) in the head that will cause the pressurization.

jim, you still running the evans coolant???

[Smokey Eddy]

jeeze you guys are smart!
I'll get 50% of that water out of there but im still trying to figure out this stupid gauge.

on the head. It's one of the 2 connectors on the front coolant flange. The other is the GP controller

Does anyone know which is which? and what stock colour wire goes to which?