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Hi Everybody - I have to say this car is frustrating me. I installed an All Season (I think thats the brand) heater valve about three years, replacing an OEM heater valve installed by a professional Volvo shop, it was installed incorrectly and before that was another All Season heater valve installed by a different Volvo shop. I know the OEM HV was damaged by the installer by having the hose clamp to close to the junction and overly tightening it but the other two?, is something wrong or is it just bad luck? Is my car running hotter than what the gauge registers ( the needle is just barely pass 12 o'clock )? It's been like that for as long as I can remember and I've driven this car from Houston, TX to Seattle, WA and back to Houston and then back to Seattle with no over heating problems in the dead of summer.
When I installed the last heater valve I replaced the water pump and thermostat. It was about five months ago I had a garage replace my antifreeze so it was fresh but they didn't do a complete flush because they said the old antifreeze looked good. Should I be using the Volvo antifreeze and maybe something else to make it run cooler? Any ideas what might be going on?
Thanks again!
GothM
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I had a 4 seasons one fail on me after 5 years. Leaking at the seam.
The Volvo one from Tasca is $65 plus shipping. If it is a superior workmanship, I would say it was a good investment for something that critical.
--
Paul NW Indiana '89 744 Turbo 175K/ '90 745 turbo 145K
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I'm might be ordering one here soon.
Was your Four Season heater valve leaking at the very bottom?
Thanks,
GothM
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This is another reason to install a loss of coolant sensor as described in the FAQs:
http://www.brickboard.com/FAQ/700-900/Cooling.htm#LossofCoolantSensorforVolvo740940Cars
I have installed 8 of them over many years in 1 740 and 7 940s and the peace of mind is worth the cost.
--
Mine: 4-940s running, 2-740 and 1-940 parts cars, and 3 1959 John Deere 630s (1 for parts), dtr1:3-940s, dtr2:1-740
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Dear GothM940,
Hope you're well. How did these heater valves fail? Did they break apart, causing loss of coolant? Did they fail internally, allowing hot coolant to flow, when heat wasn't needed (or vice versa)?
Heater control valves need to be installed with some care, because one end (and on some heater valves, both ends) are made of plastic, not metal.
The hose clamps at either end of the heater valve should be tightened completely only after the hose-and-valve assembly has been installed. The reason: the heater valve sits between two short sections of hose. Those short sections of hose are created, when the factory-supplied hose is cut, between two factory-printed marks, to allow the heater control valve to be installed. Once the heater control valve's nipples have been pushed into the cut-ends of the factory-supplied hose, the assembly should be installed. Installing the hose-and-valve assembly may require twisting the hose, to get it seated onto the nipples at either end (the head and the heater core).
That twisting can stress the valve's plastic nipple(s), if the hose clamps - at each end of the heater valve - have been tightened. Once the hose-and-valve assembly has been installed, the marks on the hose (that show where to cut the hose, so the valve can be installed), should be checked to ensure they align, just as they did before the hose was cut.
If these factory-printed marks align - just as they did, before the hose was cut - then you can be sure that the hose has not been twisted, and that there's no stress on the heater valve's hose nipples.
Hope this helps.
Yours faithfully,
Spook
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Hi Spook! I found out how fragile they are when I went to change my water pump three years ago and discovered the heater valve as the source of loss antifreeze. So when I installed the new one I was very careful to get it right which I think I did.
I haven't removed the heater valve yet as it was dark when the tow truck got us home last night, but it looked like the very bottom of the valve when it happened. I'll be going out to remove it here in about an hour and will report my findings.
Thank you so much Spook for your help!
GothM
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a 940 temp gauge registering just right of 12 is perfectly normal. mine has never registered anywhere else under all conditions.
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I have had two burst on me and and one disentegrate in my hands as I removed it.
The problem is simple, thin cheap plastic. Even the Ford replacement version you will see mentioned on this board has a Metal top but a plastic mid section. 3-4 years max seems about right for a lifespan(less for Turbo). I have been toying with the idea of figuring out which other heater control valve I could replace it with that is ALL metal, next time I replace. Something like this one:
http://www.fcpeuro.com/products/jaguar-hvac-heater-control-valve-vanden-plas-xj6-xjrs-cbc002536?gclid=CLy1q8LVj70CFZRr7AodfBYAQQ
Just needs to be same diameter inlet outlet and be sensitive to the same level of vacuum. One of these days...
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Dear The Rod,
Hope you're well. I'm intrigued by the all-metal Jaguar heater valve. I did some homework. the Jaguar heater control valve's hose nipples are for 5/8" internal diameter hose. If I recall correctly, that's the internal diameter of the Volvo heater hoses. Second, the Jaguar heater control valve closes, when vacuum is applied. I think that's how the Volvo heater control valve works. If my conclusions are correct - and I'd appreciate your thoughts - then an all-metal Jaguar heater control valve should work just fine.
The only question: how a Jaguar heater control valve will install.
Hope this helps.
Yours faithfully,
Spook
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Dear Fellow Brickboarders,
Hope you're well. I acquired an aftermarket version of the Jaguar heater control valve.
This all-steel valve is made of heavy-weight metal. The plate, on which is mounted the valve body, is about 3/32" thick.
The valve body is held to its mounting plate by four tabs, which are bent flat. I cannot imagine the valve body could separate from its mounting plate. This valve body mounting plate is affixed to the steel actuator enclosure, by three metal tabs, which are bent flat.
Key point: the valve body is all steel. Even if the actuator failed - or the valve body mounting plate separated from the actuator enclosure - there would be no coolant loss.
The only way coolant loss could occur is if one of the hose nipples separated from the valve body. The hose nipples seem to be welded to the valve body.
The hose nipples are the same diameter as are those on the factory-supplied heater control valve.
If this valve has any "weak point" it is the nipple, onto which the vacuum hose is affixed. Were this nipple to break-free, there would be no coolant loss. However, it would not be possible to stop the flow of hot coolant through the heater core.
This Jaguar heater control valve - when no vacuum is applied - is open, allowing hot coolant to flow through the heater core.
My only question: is the vacuum - normally supplied in a 940 - enough to close this heater valve? It is hard to access the vacuum hose that serves the heater control valve. I'll try to do so. If I can connect the vacuum hose to this Jaguard valve, I'd expect to see whether or not it closed the valve.
I'll report as to whether or not a 940'ss vacuum suffices to close the heater valve. If so, then this Jaguar valve would seem to be an upgrade for the all-plastic, or plastic-steel heater control valves.
I hope these comments are helpful.
Yours faithfully,
Spook
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Very interesting Spook, I'd like to know.
On one of my cars I installed a Chevy Astro valve that was researched by someone on TB. This one is plastic, but it has 4 inlet/outlets, thus bypassing the core completely when closed. This seems to make the flow through the head better, thus cooling it better. Some of these have been installed on Volvos for a few years now with no failures.
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Jerry,
Do you happen to know the part number for the chevy astro valve.
Thanks,
Speedy
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Here's the story and the no.
http://forums.turbobricks.com/showthread.php?t=246617
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Wow!, that surprises me, a little. I had almost the same experience as you except the ford version was put in with the clamp to close to where the nipple joint is... very thin plastic there. Anyway, it's good to hear it's not me or my GothM. However, what if when running the fan/blower inside the car and the air diminishes but the blower/fan is still working just fine. It's like a diverter door closes on it's own then slowly opens back up when it wants to. Would that build excess pressure on the heater valve?
Thank you for the link.
Thanks for your help!
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Negative, The fan is simply blowing air across the Heater core to gain its heat. No way it could cause the pressure in the Heater Valve to increase. The amount of pressure in your coolant system is regulated(stopped from going to high) by the cap on the expansion tank. Many of us with NA engines have started using the "Black caps" as they maintain a lower pressure. Not sure if I would do so in a Turbo engine. The higher the pressure the higher the higher the boiling point. Turbo's run hotter than a NA so you may need that higher pressure...dunno.
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Okay, that's good to know. Also, I was just looking at the black cap but like you said the Turbos run hotter so I'll just leave that alone and address the inside car vent system separately when I can get to it.
Thanks again Rod for your help.
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