El Dingo Posted May 8, 2006 Report Posted May 8, 2006 No airlock probs on 2.3 (edit) I haven't had any... :blink: Quote
johnb80 Posted May 9, 2006 Report Posted May 9, 2006 Why bother, he's boiled the 'stat and it don't work? It's a lot of work on the VR6 to fiddle about and do the job twice for no reason! Consider fitting the Neuspeed 70C 'stat, it makes the engine and oil run cooler giving slightly better performance and MPG. Get it here: http://www.awesome-gti.co.uk/shop/customer...&cat=398&page=1 Cheers. I find this amazing IF running at 70 deg was beneficial why wouldn't VW do that as standard? No cost involved, increase MPG etc etc it would be a marketing mans delight. Engine running temperatures are critical for correct operation, they will have been optimized by the designers and manufacturers during development. I personally don't see how running cooler will hep MPG figures, the oil will be thicker causing more drag for one. Regards - JB Quote
sepulchrave Posted May 9, 2006 Report Posted May 9, 2006 Optimized for which climate/market? Don't kid yourself, this (2.8 version) is a low volume model sold throughout Europe from the Artic circle to the Equator! I've said it helps and it does! :huh: Quote
johnb80 Posted May 9, 2006 Report Posted May 9, 2006 Whoa, I'm not calling you a liar and if you got that impression I offer you my sincere apologies. By nature I'm a questioning sole and hence my response. You say for which climate in my opinion thats irrelevant, the engine running temperature is optimised to be right. The ability of the cooling system to cool can only be changed by size of radiator or coolant flow, i.e. hot country = bigger rad. So as I said before why would running at a lower temp improve matters, I really don't see how it can. Only my view, if you say it works then it must work but WHY? Regards - JB Quote
sepulchrave Posted May 9, 2006 Report Posted May 9, 2006 To be fair, this is a problem which the Golf VR6 community noticed first. Large engine in a small engine bay, with a small frontal area. VW fitted a double depth rad but it's basically the same frontal area as all the other Sharans et al. The engine heats up so quickly of a morning that an auxilliary heater would never be needed even in Antarctica! All that the 70c thermostat does is open fully 10 degrees earlier, reducing the heatsoak phenomenon under normal driving conditions. As soon as you hit a traffic jam it makes no difference at all. With my old thermostat, since I live in the countryside, the temperature needle would hit halfway and then stay there unless heavy traffic were encountered. Now it sits at one third under the same circumstances. More importantly the Oil temp. as indicated by the MFA used to be around 105c, it's now about 97c. I know it doesn't sound a lot, but I can assure you that the torque and flexibility of the engine has improved noticeably, and I swear that I'm getting another MPG or two (and at the current prices that's a big deal!) and I'm equally certain that the oil will be in better condition as a result. I know you weren't calling me a liar, I was just nipping at your 'who's that trip trapping over my bridge' routine. :blink: Quote
johnb80 Posted May 10, 2006 Report Posted May 10, 2006 No problem, thanks for the explanation. Regards - JB Quote
tim-spam Posted May 10, 2006 Report Posted May 10, 2006 However, speaking as an experienced automotive design engineer, JB was quite right. Yes, you may benefit from a 'cooler' thermostat in southern Spain, and you may benefit from a 'hotter' thermostat in Finland, but the effect is very small on modern engines, as the proportion of heat dissipated from parts other than the cooling system is very small indeed. In addition, modern engines are installed such that induction air is taken from outside of the engine bay, so that underbonnet temperatures have a much smaller effect on engine performance and emissions. Leaving the thermostat out altogether will increase the engine running temperature, as, when the thermostat opens all the way, it blocks off the radiator bypass - without the thermostat, some coolant will always bypass the radiator. Quote
johnb80 Posted May 10, 2006 Report Posted May 10, 2006 Leaving the thermostat out altogether will increase the engine running temperature, as, when the thermostat opens all the way, it blocks off the radiator bypass - without the thermostat, some coolant will always bypass the radiator. Never knew that, just shows, 35 years of experience working on cars (not professionally) and a forum like this adds to the knowledge every day :blink: Quote
Masked Marauder Posted May 10, 2006 Report Posted May 10, 2006 Well I am going to put my tuppence in here. I have NEVER ever owned a car that ran hotter with no thermostat in. As for blocking the bypass, every car I have owned the thermostat housing has been a simple open or shut design and fluid dynamics dictate water will take the least course of resistance so the system is designed to take advantage of that. If the stat is shut the water is forced round the engine again through a smaller pipe at a higher pressure. when the stat is open it flows through the less-ressistant radiator. With no stat blocking the rad off then this is even more the case. Quote
tim-spam Posted May 10, 2006 Report Posted May 10, 2006 With no thermostat in place, the engine will run cooler, and take longer to warm up, as there will be coolant running through the radiator. That is, until the engine is loaded to the point where maximum cooling capacity is needed - eg: in hot ambient temperatures, pulling hard at low speeds, etc. - then the cooling capacity will be reduced due to the coolant flowing through the bypass. Thermostats which block the bypass when fully open are becoming much more common as engines produce more heat due to ever more stringent emission regulations. Quote
Masked Marauder Posted May 10, 2006 Report Posted May 10, 2006 I can see that I am going to have to catch up with modern engines at some stage. Quote
tim-spam Posted May 10, 2006 Report Posted May 10, 2006 All that's normally involved is a spring-loaded disc at the bottom of the thermostat, which seats against the radiator bypass inlet when the thermostat opens. My wife's Mercedes 190D has such an arrangement, and I would guess (although I don't actually know for sure, as I haven't seen it) the VR6 engine would be a very likely candidate due to its compact design, and the need to maximize the heat dissipation capacity in the smallest possible space. Quote
Guest Sword Posted May 12, 2006 Report Posted May 12, 2006 well, changed the stat (housing aswell, but thats a different story) Put some G12 in, left my expansion cap off and ran car until rad fan came on, normally before, the rad fan would come on around 7/8 on the scale. Now it came on at not even 2/3 on the scale and the temp guage dropped to 1/2. I am soooooooo happy, you cannot imagine. Thankyou all once again, for your tips and knowledge. Lets hope i get at least "some" trouble free miles again. Quote
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