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Coolant problem on facelift 1.4

3880 Views 8 Replies 4 Participants Last post by  r44712
Hi All i have a 05, facelift zr, 1.4, I bought it new, its all original.
Some time ago the heater stopped blowing warm. I traced this to a plastic (With saab cast on it, is it a bypass?) valve under the bonnet.
I replaced this with one from a 05 zr scrapper, as rover garage hadn't seen one before.
Anyway, this replacement one went a while ago. When the valve is good, there is a silver ball inside. when duff, this ball becomes lost inside the engine somewhere.
Now, after any short or long drive, the water in the header tank is boiling, fan always on, radiator top hose is rock hard, bottom hose is soft and freezing. (I've proven rad is clear.) The temp gauge never rises above where it always has been. I'm starting to worry i am doing damage by overheating parts of the engine.

Where might the 2 balls be? (Nothing rude here please, lol)
The oil is clean, and it uses water, probs due to the boiling up, and forcing its way out of the tanks lid.

I dumped the water system when i changed this valve thing last time, but struggled to get it to bleed fully. mite this be cos of the original ball blocking somewhere.

Any help would be great, thanks in advance.

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Definitely sounds like there is an air lock in the system, so first thing I would do is bleed it again and see if that sorts it, if bled properly it should blow out warm air.
just remembered, when its on tick over, it blows cold, rev it, and it blows warm, drop revs, temperature drops. (Once engine is warm obviously). I have tried an tried bleeding it. all seems ok, water come from the nipple, all hoses feel right, till i drive it. then, its boiling up again.

Hmm, it could be the coolant expansion tank cap, so basically the screw on lid for the coolant tank. These can let steam escape from them causing the cooling system to malfunction, they only cost £5 to replace, so I would try that.

Are there any sort of leaks?

I just don't understand what this 'ball' thing is?

Thanks for the rapid replies,
These are two of the valve things. the ball is, or was in the large chamber in the middle, and visible from the end pipe that goes straight to it. it could be pushed in with a screwdriver, like its on a spring. (Did this 2 see what it was once original 1 broke. gently does it) hope its of some use. From what i have seen, its only on some of the facelifts, and a 90something saab 900 turbo. i am wondering if the waterpump is broke (Blocked or destroyed by the balls) hence the rev an heat, slow and cool characteristics. Its also pressuring right up. with the cap off the water expands above the max, and out of the top, and then boiling water/bubbles replaces it. rad top pipes remain pressured rock hard.

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Does anyone else have problems with this saab thing?
Might it be the broken off balls blocking the system, if so, where might they be, how do i remove?
Could the water pump be duff, . (Engine has 76k)?
Should the bottom hose always be freezing, and soft, with the top rock hard and red hot?
Can i modify the system to remove the saab thing, or replace with something more reliable?

Any helps greatly recieved.

Hi All. does anyone know which way the water goes around the pipes and engine? I'll take off pipes and try to back flush if possible.

Thank you, Stu
This problem has come up a few times and it seems that this valve is very unreliable. The original system just had a restrictor instead of a valve and I would think that this would be an easy mod to make. However, the missing ball has got to be found first because it sounds like it is causing a blockage, possibly in the hose to the heater. If the flow through the heater (or the valve when the heater is set to cold) is stopped, the thermostat will not see hot water and will never open.
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