Rich Posted October 26, 2012 Author Report Share Posted October 26, 2012 Yes I know this, damn emissions....who cares! My old Mondeo diesel still managed 35 mpg driving around town and that took twice as long to warm up. The Corolla is warmed up within 5 minutes, although that will increase now with winter on the way. Would allowing the car to idle for a couple of minutes before setting off help? I usually start the car and drive off straight away, would it use more fuel idling or driving from cold? Another thought is I've only ever had winter tyres on this car as I got them fitted a few weeks after buying it but they shouldn't make that much of a difference in mpg? Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted October 26, 2012 Report Share Posted October 26, 2012 Cold start inefficiencies is nothing new. A carbed engine need a choke to get started, just like my bike did, and my snowmobile, and my lawnmower...weedwacker... ok you get the point. It has nothing to do with warming them up quicker, it's the only way to get them to start since you are combating against extra friction fuel condensation. This article helps with why gasoline cars need more fuel on start-up. Diesels are not affected by this as much and usually will not see as large of a MPG drop during warm-up. Partially because the engines chamber temps tend to be a bit cooler unless you start looking at some of the hopped up diesels. The reason why modern engines warm up quicker is the engines nowadays have a higher specific output (HP per cyl), use lighter alloys that transfer heat better and use lighter weight oils that warm up quicker than they did 30 years ago. Aluminium is a great thermal conductor, where cast iron is not. To answer your question about idling. IMO give it 30 seconds to get the top end of the engine lubing up and drive it lightly until the temp gauge reads 'normal'. It's not for fuel consumption, but engine wear, as much as 90% of engine wear will occur during warm-up and cool-down due to different metals heating and cooling. Different metals react differently to the same temperatures. The only thing you can do to help fuel economy during warm-ups is to warm up as quick as possible, without damaging the engine. When you figure something out that achieves both at the same time, let me know =) Quote Link to comment Share on other sites More sharing options...
liner33 Posted October 26, 2012 Report Share Posted October 26, 2012 Having custom mapped cars I can assure you they are mapped not just to start and run better when cold but to warm up quicker , also most modern engines run at a higher temperature than older ones meaning its even more important to get them up to temps quicker and finally catalytic converters need high temperatures to operate properly so the quicker a car gets up to temp the cleaner it is That's why most people report better economy in the summer than the winter even when taking in the impact of air con , my diesels were noticeably worse on fuel during the winter and diesels take a lot more warming up. My Mercedes diesel was mapped to add lots more fuel if the air temperature dropped below 7 degrees . The best and quickest way to warm an engine up is to drive it , gently at first , modern oils have made the need f or idling superfluous and will just waste fuel I fear there is not a lot you can do to improve your consumption you have done the obvious things so it is what it is I'm afraid For the miles you do I expect the difference between your car and one doing an extra 5mpg will be less than a Tankful a year if that makes you feel better Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted October 27, 2012 Report Share Posted October 27, 2012 Ok Liner... the tune is the reason the car warms up quicker. =) Fuelly has some tips to save fuel that might help a little. Here Quote Link to comment Share on other sites More sharing options...
Rich Posted October 31, 2012 Author Report Share Posted October 31, 2012 I've had a very good quote on a Legacy GTB, not much more than the Corolla so I may get one next year. If I'm only going to get 23 mpg I'd rather do it in the Legacy. It'll cost abit more in fuel having a larger tank and running on V Power but it would only be around £10-£15 a month. A small engined car seems to be a no go so my only other option would be to get another diesel but then there's no fun in that! Think I need to get this out of my system before going back to an oil burner. For the miles you do I expect the difference between your car and one doing an extra 5mpg will be less than a Tankful a year if that makes you feel better Yes you're right, the difference between 23 and 28 mpg is around £70 odd a year. Fuelly has some tips to save fuel that might help a little. Here Some good tips there, some I already do. What about when I'm waiting for the missus at the local shops, sometimes I sit there with the engine idling for 5 minutes or so, should I turn it off or would it use more fuel starting it up again? Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted October 31, 2012 Report Share Posted October 31, 2012 sometimes I sit there with the engine idling for 5 minutes or so Turn it off if it's going to more than about 30 seconds. Quote Link to comment Share on other sites More sharing options...
Rich Posted October 31, 2012 Author Report Share Posted October 31, 2012 sometimes I sit there with the engine idling for 5 minutes or so Turn it off if it's going to more than about 30 seconds. Will do...I don't do it often but always wondered if I should or not. Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted October 31, 2012 Report Share Posted October 31, 2012 Will do...I don't do it often but always wondered if I should or not. Mine does it for me after about two seconds, providing no temperature extremes or lowish battery charge Quote Link to comment Share on other sites More sharing options...
Sagitar Posted October 31, 2012 Report Share Posted October 31, 2012 Forgive me if I don't join the bragging . . . Quote Link to comment Share on other sites More sharing options...
Vipercar93 Posted October 31, 2012 Report Share Posted October 31, 2012 If you swap to a V8, in those driving conditions you will be lucky to see 16-18mpg I bet. It's not the car that is giving you bad MPG. I admit guys I am a bit jelious, always wanted a car with all the frills, at least when I am toting around the family Quote Link to comment Share on other sites More sharing options...
Rich Posted November 1, 2012 Author Report Share Posted November 1, 2012 Forgive me if I don't join the bragging . . . Ah, but is your car as much fun to drive as mine! Shame you can't have the best of both worlds! If you swap to a V8, in those driving conditions you will be lucky to see 16-18mpg I bet. It's not the car that is giving you bad MPG. I admit guys I am a bit jelious, always wanted a car with all the frills, at least when I am toting around the family I don't want to swap to a V8 though, maybe a V6 or a turbo. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 2, 2012 Author Report Share Posted November 2, 2012 Can anyone recommend the cheapest place to get a Denso (OEM) O2 sensor? I'm thinking I might replace it anyway and see what happens as it's getting on for 10 years old now. Quote Link to comment Share on other sites More sharing options...
Tony Posted November 2, 2012 Report Share Posted November 2, 2012 Eurocar are good. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 2, 2012 Author Report Share Posted November 2, 2012 I looked last night and they had none in stock, just checked now and they have! It's £58 with a discount code. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 6, 2012 Author Report Share Posted November 6, 2012 Anyone know why a car would lose coolant when only the heating is used? I've noticed I have to top mine up when it's been used as it goes down but there is no sign of a leak. Quote Link to comment Share on other sites More sharing options...
phipck Posted November 6, 2012 Report Share Posted November 6, 2012 A leak is the only thing i can think of, could be a minor leak and with the temp of the liquid it would most likely be evaporating off quite quickly. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 6, 2012 Author Report Share Posted November 6, 2012 But it's only when I use the heating, if I don't use it the coolant level stays where it is. If it was a leak surely it would constantly lose coolant, this is what's puzzling me. I know the earlier Corolla's (01-03) had issues with the heater matrix blocking up and not working but I don't think this is the problem. Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted November 6, 2012 Report Share Posted November 6, 2012 Sounds like you have a leak in the heater matrix, when you let the water flow through and it's hot it's escaping. Get some leak stuff in the radiator quick to see if it fixes it .... if it doesn't then you will have a pain of a job to replace the heater matrix ( well it is in most cars ). How much is it losing? Quote Link to comment Share on other sites More sharing options...
Rich Posted November 6, 2012 Author Report Share Posted November 6, 2012 Sounds like you have a leak in the heater matrix, when you let the water flow through and it's hot it's escaping. Get some leak stuff in the radiator quick to see if it fixes it .... if it doesn't then you will have a pain of a job to replace the heater matrix ( well it is in most cars ). How much is it losing? Someone else on the Corolla forum said he has the same problem (in fact a few do) but he said he can sometimes smell coolant inside the car as well, which is making me think it could be the matrix. Someone has said they've managed to replace it with just removing the glovebox so it might not be too bad but obviously another expense I could do without. When I bought the car last October the coolant level was very low, just above minimum so I topped it up with water so it was halfway. Really I should've used pink coolant but didn't have any. That was fine until the start of this year when I had to top it up again as I had been using the heating throughout winter, although I don't have it that hot, maybe a max of 22 degrees. It didn't use any coolant during the summer months as I don't have the heating on but now that I am I've noticed it's going down again. The heater matrix is like a small radiator isn't it so rad weld should be ok to use in the system? Or what about K-Seal? I'm weary of these products though as some people say never use them, they damage the system and others think they're fine. Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted November 6, 2012 Report Share Posted November 6, 2012 Product to choose is a matter of "choice" as you say different opinions. Wait for comments good or bad ........... Quote Link to comment Share on other sites More sharing options...
phipck Posted November 6, 2012 Report Share Posted November 6, 2012 Sounds like you have a leak in the heater matrix, when you let the water flow through and it's hot it's escaping. Get some leak stuff in the radiator quick to see if it fixes it .... if it doesn't then you will have a pain of a job to replace the heater matrix ( well it is in most cars ). How much is it losing? this is what i meant by a leak, if it drops when using the heater it has to be the matrix. The smell will also definately be a strong sign that this is the case Quote Link to comment Share on other sites More sharing options...
Rich Posted November 6, 2012 Author Report Share Posted November 6, 2012 Certainly sounds like the matrix. I'll check the hoses in the engine bay that connect to it but if they're ok I'm not sure whether to replace it (I think £90 for a pattern part) or put radweld in. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 9, 2012 Author Report Share Posted November 9, 2012 How does the heater matrix work, does coolant run through it the whole time, what happens when you turn the heat up and down, does this cause the matrix to behave differently? Any more thoughts on using radweld or similar then? Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted November 9, 2012 Report Share Posted November 9, 2012 The matrix works like a radiator at home. There is always water in it from the main cooling system and when heat if off then a valve is closed so no through flow. As you increase the temperature the valve opens more and when it's on max. it's fully open. If you look under the bonnet you should see the valve with a cable that operates it. I'd say try a sealant first and see if it works ( follow instructions and make sure heater is on max temperature ), if it doesn't then you have a bigger job on your hands. Quote Link to comment Share on other sites More sharing options...
Rich Posted November 9, 2012 Author Report Share Posted November 9, 2012 So the more the valve opens the more pressure there will be inside the matrix? So if there is a leak from the fins the extra pressure is forcing it out, is that right? I'll try some radweld then and will make sure it's on max temperature Quote Link to comment Share on other sites More sharing options...
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