shawshankkid 1 Posted December 15, 2015 Hi all, I need to change my thermostat, my heater has become luke warm so I'm guessing it's jammed..it has been on 12 years while I've had it, and then the time before that. I've read a few posts but there a bit conflicting. Can it be done without taking any belts off ? I've also bought a new plastic housing as a few have said it's likely to crack and break. Any help much appreciated. Thanks chris. Quote Share this post Link to post Share on other sites
Yandards 0 Posted December 16, 2015 It might not be the thermostat that is stuck, it could be the thermal bypass to the heater matrix is going. If you look in the engine bay near the bulkhead around where the ignition coil lives there should be a aluminium coloured valve with 3 hose connections on it - this is there is prevent hot coolant from flowing into the car if the heater matrix fails. This was all done as part of a recall program and if you have replaced the heater matrix then the same mechanism is incorporated into the newer matrix so you can remove the aluminium valve from the hoses. If it is a thermostat replacement you need to do then its not possible without dropping the power steering pump out of the way so you will need to remove the V belt that drives this - you don't need the charger belt off though. Top tip is to use a little bit of Vaseline to help glue the thermostat and seal in place. Quote Share this post Link to post Share on other sites
shawshankkid 1 Posted December 16, 2015 Hey yan, nice to hear from you. Thanks for the advise, to my knowledge the heater matrix has never been changed. Would you try the thermostat first ? Quote Share this post Link to post Share on other sites
Yandards 0 Posted December 16, 2015 It wont hurt to do the thermostat although if you have not removed the PAS pump before there are a lot of hidden bolts to get undone. I would be looking at your coolant gauge temps - if they are in normal range for the car then it is unlikely to be a thermostat issue as if its making the heater run cold it has to be stuck open to do that. They tend to be pretty reliable things as they are always submerged in coolant and move/operate when you drive the car. You don't need to change the matrix to replace the valve as you can source 2nd hand items that will hopefully work. Can't find a part number as they are not listed in ETKA as it was a recall job issued via a service bulletin. Quote Share this post Link to post Share on other sites
shawshankkid 1 Posted December 18, 2015 Many thanks for the advise yan. Do I just look for a heater matrix valve then ? Or is there another name for it ? Thanks again. Quote Share this post Link to post Share on other sites
Thursdave 10 Posted December 19, 2015 It might not be the thermostat that is stuck, it could be the thermal bypass to the heater matrix is going. If you look in the engine bay near the bulkhead around where the ignition coil lives there should be a aluminium coloured valve with 3 hose connections on it - this is there is prevent hot coolant from flowing into the car if the heater matrix fails. This was all done as part of a recall program and if you have replaced the heater matrix then the same mechanism is incorporated into the newer matrix so you can remove the aluminium valve from the hoses. Interesting! I wondered about what this was when doing the matrix on my G60. Did it before I started driving it properly but my heating has always been tepid, which combined with a coolant temp gauge that always reads very low, I figured it was a stuck thermostat, however the fan comes on normally, so perhaps instead of the stat it's a temp sensor and this silly valve? What would you do with the spare hose once you've removed the valve? Quote Share this post Link to post Share on other sites
Yandards 0 Posted December 19, 2015 Many thanks for the advise yan. Do I just look for a heater matrix valve then ? Or is there another name for it ? Thanks again. If you can find one, breaker would be easiest and its a heater matrix bypass valve IIRC. Thursdave, if your heater is constantly blowing tepid along with a low reading coolant gauge I would go with a sticky thermostat as the fan controller system uses a different temp sensor than the gauge. Ideally you would replace the coolant pipe if you have removed the valve as the original recall called for a section of pipe to be cut out, so you should end up with only two coolant pipes going up to the bulkhead post heater matrix change due to the valve being incorporated into the heater matrix assembly. Quote Share this post Link to post Share on other sites
shawshankkid 1 Posted December 19, 2015 Top info Yan thank you. I'm having a full respray in march £3500 ...be like new again. Quote Share this post Link to post Share on other sites
