BrianR Posted February 3, 2009 Share Posted February 3, 2009 About a year ago I noticed that the coolant was taking a very long time, if ever, to get up to normal temperature. It would reach it after a steep hill climb in low gear. Sometimes, once this had happened the temperature would then revert to normal. The problem gradually got worse so I had a new thermostat fitted last August. This did the trick for a few weeks but then the problem returned. When I got back to the UK last November the garage repaced the thermostat FOC. Again, everything was OK, even in the early January cold spell. However, the problem has now begun to return. The maximum the temperature will reach when at normal cruising speeds is about 5ºC below normal. It seems doubtful that three thermostats can have failed and yet replacing the thermostat temporarily cures the problem. Has anyone any ideas? Link to comment Share on other sites More sharing options...
davenewellhome Posted February 3, 2009 Share Posted February 3, 2009 How are you measuring the temperature? with the built in gauge I presume? These are notoriously inaccurate and only serve as a general guide not an exact temperature reading. If your heater is not getting warm then you might well have a problem though. D. Link to comment Share on other sites More sharing options...
Philman Posted February 3, 2009 Share Posted February 3, 2009 Have you tried a cover over the radiator grille? Quite a few vehicles do not get up to normal temperature when it is a bit chilly outside. Is the fan coming on earlier than it should, or for too long? Phil. Link to comment Share on other sites More sharing options...
BrianR Posted February 4, 2009 Author Share Posted February 4, 2009 davenewell@home - 2009-02-03 8:39 PM How are you measuring the temperature? with the built in gauge I presume? These are notoriously inaccurate and only serve as a general guide not an exact temperature reading. If your heater is not getting warm then you might well have a problem though. D. Yes, with the built in gauge - but I don't think the inaccuracy of the gauge is the problem, as it's reading indicates that the coolant reaches normal temperature after a new thermostat is fitted, but then a lower temperature some weeks later. I don't see how this could be due to an inaccurate gauge as the differences are to great and too consistant. Link to comment Share on other sites More sharing options...
George Collings Posted February 4, 2009 Share Posted February 4, 2009 I wonder if this is an electrical problem due to poor connections. Corrosion can gradully add resistance altering the temperature gauge readings. The sensor is often close to the thermostat and is disturbed when the thermostat is renewed and may remakes a good contact for a while. Try waggling the sensor connection. Sometimes the spade connetor can be very gently squeezed with pliers to cure this sort of problem. Link to comment Share on other sites More sharing options...
andy mccord Posted February 5, 2009 Share Posted February 5, 2009 Have you tried changing the temp sensor which is either in the block or the thermostat housing? I do agree its odd that it appears normal when a new stat is fitted though, maybe its a coincidence? Regards Andy Link to comment Share on other sites More sharing options...
emmbeedee Posted February 5, 2009 Share Posted February 5, 2009 Is the thermostat housing corroded, so that the corrosion is holding the 'stat partially open all the time? It is most unlikely IME to have 3 faulty 'stats. Where the faulty 'stats partially stuck open when removed? Link to comment Share on other sites More sharing options...
euroserv Posted February 6, 2009 Share Posted February 6, 2009 Hello Brian, We have encountered a similar problem twice on 1998 Fiat 2.8idTD vans. Have you noticed the colour of your antifreeze? If it is a reddish colour even if you use a blue solution you have an accumulation of silt or corrosion in the engine waterways. You will have to remove the bottom hose from the radiator and take the top cap off the header tank and flush it through with lots and lots of water. We used a hose pipe and it worked very well. I assume that your radiator is in good condition. The only other place that the silt could be 'hiding' is in the heater matrix, and you may have to get that removed and flushed out too. There are commercially available engine flushing products but when it is this far gone they may help but the hose pipe will do a better job. Nick Link to comment Share on other sites More sharing options...
BrianR Posted February 17, 2009 Author Share Posted February 17, 2009 Thanks for these suggestions and apologies for not having responded before. At the moment I am temporarily separated from my 'van, so I will not be able to follow up your sugestons until mid March. With regard to "Euroserv"'s suggestion regarding the coolant, is the problem that the "silt" stops the thermostat closing? If so, this does seem to fit in well with the syptoms. Link to comment Share on other sites More sharing options...
euroserv Posted February 17, 2009 Share Posted February 17, 2009 Not exactly, the stuff accumulates over time and just stops things flowing as they should. After a while it won't matter whether the thermostat is open or closed if the flow is restricted. Nick Link to comment Share on other sites More sharing options...
Brambles Posted February 17, 2009 Share Posted February 17, 2009 It could well be faulty thermostats, or aftermarket ones that are not compatable with the antifreeze you are using. I went through much the same with my old Sierra car - tried a couple of aftermarket thermostats and ran cold again after a few weeks. Bought a Ford one from dealer and problem solved. The way to test is when the engine is warming up, if warm water is flowing into radiator prematurely before full temp of engine has been reached. This would indicate the Thermostat is slightly open when it shoud not be during warming up. Link to comment Share on other sites More sharing options...
BrianR Posted February 20, 2009 Author Share Posted February 20, 2009 Thanks for thses replies, I will persue the matter again when I get back to my 'van. The withdrawl symptons are seting in! Link to comment Share on other sites More sharing options...
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