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Discussion Starter #1
Hi guys,

decided to replace the thermostat on the 155 this weekend, as it took longer and longer to warm up in the morning, and with the cold nights recently it stayed at 70C.
After forking out 70 euros (GBP45) for a thermostat (daylight robbery, that! what do I want with an all new housing when it's just the thermostat itself that's going?), draining the system, replacing the thermostat and refilling with coolant, the engine warms up nice and quick again, but I don't! There is absolutely no heat whatsoever coming into the car. I assume there's an air lock in the heater matrix, but how to get it out? I'm stumped. I've tried hot start, cold start, fiddling with the control while revving the engine silly, doing the same on a steep incline (yes we do have those in holland; in the multi-storey!), squeezing all kinds of hoses, but no luck.
Any suggestions, anybody? I'm beginning to wonder if I did take off all the plastic caps from the new thermostat... eek! Nahh, wouldn't have been able to get the hoses to fit over them. Would I?
 
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Discussion Starter #3
I THINK I did.... :(

Of course, having to replace the complete housing does make it all a bit more idiot proof, well resistant, perhaps.
 
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Hi, this might not be the obvious answer, but worth a try unless you've done it already, try bleeding the system from a cold start.

Remove radiator filler cap before engine is running and let warm up with it off to see if any air comes through, it may gurgle then drop down to minimum, don't do it for to long, just enough for the thermostat to open and see what happens, if there's any air it should come out throught the filler, replace cap and let cool then refill if neccessary.

You could also try putting the heaters on while your doing this

PS Don't let it get to hot and boil

Hope this helps, but do it at your own peril
 
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Discussion Starter #5
Hmmm... draining the system didn't sound like a too great idea in retrospect. When I did mine I just undid the hose on the thermostat and let the coolant tip onto the floor.

The cold start idea seems to have mileage in it. Put the heater full on, remove the coolant cap and fill it up to the max level and then as it warms up just squeeze every hose in sight to get as much air out as possible.

I don't think the 155 had an air bleed on the heater hose as some cars do, so it should be self-bleeding, I hope.

Ralf S.
 
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Discussion Starter #6
Hi all,

thanks for the suggestions. I did solve the problem eventually, and no, I'm not going to tell ANYBODY what the problem was. I'm just going to creep back into my little dark corner and sit very quietly for a very long time..... :eek:
 
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Discussion Starter #7
BTW don't forget to put the heater on full blast (hot) to ensure the water goes round the matrix too wink Presume this applies to 155's, used to on other cars I've owned :D

wrinx
 
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Discussion Starter #8
el gringo

Please come out of your dark little corner and tell us what you didn't do :D Come on lets have a laugh wink

wrinx
 
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Discussion Starter #10
Hey!!

I 'bled' the air out by removing the temp sensor on the thermostat housing whilst filling thru the expansion tank.

Just a thought

Oliver :cool:
 
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Discussion Starter #11
Oh alright then. Promise you won't laugh.

I managed to put the bottom heater hose on without taking the plastic cap off. Small wonder there was no hot air coming from the heater.

Oh stop it. You SAID you wouldn't laugh! It was dark. And it's out of sight at the bottom of the housing. And it's a VERY slim cap. And it's transparent. Sort of. Nearly invisible. Sort of. Oh bugger, I'm going back to my dark little corner.
 
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Discussion Starter #12
You should have kept that quiet. LOL.

Don't worry, bet others have done similair things but just kept quiet.

Marlon
 
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