D1 Overheating Issues -- guru knowledge required
- Thread starter d1owner
- Start date
Now that the hot temperatures have arrived I have noticed that the temp. gauge only rises when the A/C is on. Even if I turn off the A/C and am in stop/go traffic, the temp gauge will eventually come down to normal. For some reason, the A/C is putting an excessive load on the engine.
Regarding an earlier discussion in this thread about exhaust gases entering the coolant -- can this still be the problem? I would think not because it should occur regardless of whether the A/C is on or off. The temp. gauge should increase because of the hotter outside temperature and exhaust gas in the coolant system, not because of the A/C compressor.
Any thoughts?
Regarding an earlier discussion in this thread about exhaust gases entering the coolant -- can this still be the problem? I would think not because it should occur regardless of whether the A/C is on or off. The temp. gauge should increase because of the hotter outside temperature and exhaust gas in the coolant system, not because of the A/C compressor.
Any thoughts?
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syoung
Guest
If your AC compressor is starting to sieze up- it can take a lot of power to spin it, but often times that just causes the engine to stall at idle or the belt to slip and make horrid noises.
Is your secondary fan coming on with the AC?
Is your secondary fan coming on with the AC?
What do you mean by secondary fan? (are you referring to the 2 electric fans). I know that often times they run when I turn off the car for a few minutes. I do not know if they are running when the car is operating. I will need to check. Should these fans come on when the A/C is on, or only when the temp gets to a certain point. BTW, I recently had the viscous clutch replaced for the main fan.
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studio54
Guest
getting all scientific
This it totally true!
Also remember that switching the AC on also adds heat load from the AC system itself. (Energy, like matter, is not created or destroyed it is only changed from one form to another (first law thermodynamics)). The ?hot? heat exchanger for the AC is in front of the coolant radiator. This can increases the temperature of the air flowing through the coolant radiator.
According to the Second law of thermodynamics the rate of energy transferred from one medium to another increases as the difference in temp between the to mediums increases and vice versa. So the higher the temp of the air flowing thought the radiator the less heat it will carry away with it.
If part of you cooling system is not working effectively then this increase in temp and subsequent decrease in energy transfer rate may well be enough prevent adequate cooling for the engine.
syoung said:
This it totally true!
Also remember that switching the AC on also adds heat load from the AC system itself. (Energy, like matter, is not created or destroyed it is only changed from one form to another (first law thermodynamics)). The ?hot? heat exchanger for the AC is in front of the coolant radiator. This can increases the temperature of the air flowing through the coolant radiator.
According to the Second law of thermodynamics the rate of energy transferred from one medium to another increases as the difference in temp between the to mediums increases and vice versa. So the higher the temp of the air flowing thought the radiator the less heat it will carry away with it.
If part of you cooling system is not working effectively then this increase in temp and subsequent decrease in energy transfer rate may well be enough prevent adequate cooling for the engine.
I noticed that only one of my electric fans is working. But I am not sure if the other one is designed to go on only when the engine/coolant reaches a certain temperature.
Let me ask another simple question...Is it possible for the fans to be connected in such a way that they rotate in the wrong direction, i.e. drawing heat into the radiator? Or is the connector for these notched so that it can only connect (and therefore spin) one way?
Let me ask another simple question...Is it possible for the fans to be connected in such a way that they rotate in the wrong direction, i.e. drawing heat into the radiator? Or is the connector for these notched so that it can only connect (and therefore spin) one way?
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studio54
Guest
fix the fan
if only one of your fans is working you need to fix it. They come on together. As for Reverse polarity of fans, it should not be possible but??????. just feel which way the air is moving
if only one of your fans is working you need to fix it. They come on together. As for Reverse polarity of fans, it should not be possible but??????. just feel which way the air is moving
ptschram
Well-known member
The fans are AUXILIARY fans-if the fans are needed in everyday usage, the radiator is likely toast.
Replace the radiator before you need to replace the engine.
It seems s though you are trying as hard as you can to not replace the radiator even though the preponderance of the evidence points in that direction.
Replace the radiator before you need to replace the engine.
It seems s though you are trying as hard as you can to not replace the radiator even though the preponderance of the evidence points in that direction.
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syoung
Guest
When radiators get old, aside from getting clogged with crap they also lose their ability to transfer heat. The metal from which they are made fatigues and loses the capability.
ptschram
Well-known member
syoung said:
The tubes become coated with silicates and other contaminants that limitss the thermal transfer. some radiator shops claim that even with chemical cleaning, some remains and drasticlly reduces efficiency of the radiator.
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studio54
Guest
more
D1,
I do not think you can repair the fan however thinks to check are:
1 does the blades turn easily by hand? If no then a bearing has gone.
2. apply direct power from the battery and check all the wires, it is amazing how often electrical problem come down to broken wires. Look for any place that the wire bends differently.
Time for a disclaimer: If it dose not work what have you got to lose by removing it and trying to fix it? I am a big fan of trying PROVIDED ONE IS MECHANICLY COMPITENT if you are unsure then please do not listen to me!
Re radiator. It sounds a lot like it needs to be looked at. I would defiantly try to get the fan working as it will affect cooling and a/c efficiency however it sounds a lot like there is insufficient heat transfer from coolant to air. One more thought, your radiator is not full of bugs and mud is it? Radiators have to be clean inside and out to work effectively.
D1,
I do not think you can repair the fan however thinks to check are:
1 does the blades turn easily by hand? If no then a bearing has gone.
2. apply direct power from the battery and check all the wires, it is amazing how often electrical problem come down to broken wires. Look for any place that the wire bends differently.
Time for a disclaimer: If it dose not work what have you got to lose by removing it and trying to fix it? I am a big fan of trying PROVIDED ONE IS MECHANICLY COMPITENT if you are unsure then please do not listen to me!
Re radiator. It sounds a lot like it needs to be looked at. I would defiantly try to get the fan working as it will affect cooling and a/c efficiency however it sounds a lot like there is insufficient heat transfer from coolant to air. One more thought, your radiator is not full of bugs and mud is it? Radiators have to be clean inside and out to work effectively.
Everyone, thanks for the inputs.
PTshram, I do not believe (or want to believe) it is the radiator. The problem only occurs in hot weather with the A/C on. If I had a radiator problem, it would show signs more frequently with the A/C off. I tested the radiator's cooling ability the other day. It was like 94 degrees outside and I was driving in stop/go conditions with the A/C off. There was no movement of the coolant gauge.
Also, although I have quite a bit of mileage 198K and the radiator was replaced at/about 110K, I have had (noticed) these overheating issues at about 30K into the radiator -- the time it took from replacement (in late fall) to early summer -- I drive a lot. I would not have noticed this problem during the cooler months anyway.
I think the simpler and more cost effective route is to fix/replace the aux. fan first and then go from there. As I indicated in my first post in this thread, I have replaced most, if not all, coolant related components and I believe the dealer probably overlooked the broken fan. I am not saying that the other components did not require replacement, but they probably could have lasted a bit longer.
If all else fails, the radiator will need to get replaced. I have heard that getting them rodded is only a temporary fix and that a new one is probably the better choice.
PTshram, I do not believe (or want to believe) it is the radiator. The problem only occurs in hot weather with the A/C on. If I had a radiator problem, it would show signs more frequently with the A/C off. I tested the radiator's cooling ability the other day. It was like 94 degrees outside and I was driving in stop/go conditions with the A/C off. There was no movement of the coolant gauge.
Also, although I have quite a bit of mileage 198K and the radiator was replaced at/about 110K, I have had (noticed) these overheating issues at about 30K into the radiator -- the time it took from replacement (in late fall) to early summer -- I drive a lot. I would not have noticed this problem during the cooler months anyway.
I think the simpler and more cost effective route is to fix/replace the aux. fan first and then go from there. As I indicated in my first post in this thread, I have replaced most, if not all, coolant related components and I believe the dealer probably overlooked the broken fan. I am not saying that the other components did not require replacement, but they probably could have lasted a bit longer.
If all else fails, the radiator will need to get replaced. I have heard that getting them rodded is only a temporary fix and that a new one is probably the better choice.
d1owner said:Everyone, thanks for the inputs.
PTshram, I do not believe (or want to believe) it is the radiator. The problem only occurs in hot weather with the A/C on. If I had a radiator problem, it would show signs more frequently with the A/C off. I tested the radiator's cooling ability the other day. It was like 94 degrees outside and I was driving in stop/go conditions with the A/C off. There was no movement of the coolant gauge.
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see thats the problem...you dont want to believe
but I would have to say he is correct, why? you ask...because he has had a bunch of these into his shop with the same problem. because there have been 50 people on this board in the last year or so with the identicle symptoms that fixed it with a new rad.
this board works if you let it...people all have the same situation with the same vehicle it becomes clear that that vehicle tends to do that or act that way.
BOTTOM LINE
when the radiator on a disco starts to get plugged it often can still cool the engine under most circumstance because it is so large that at even reduced capacity it can still do its job. Add in the extra heat energy of the AC condensor raising the temp of the inbound air across the radiator and the less then optimum radiator can no longer do its job. It then starts to heat up and up and up till you turn off the AC and remove the source of the heat.
this is a known problem...believe it and get a new rad before you cook the engine and warp the heads ect ect
MM
I have to agree with Musky here. I had these same symptoms. It would run on the hot side in hot weather and once the A/C was put on it would climb way up. It would be fine in cold weather. Still on the warm side though. I was bashing my brain trying to figure out what this was until one day I just decided to pull the radiator out. In the pic you will see that almost half of the radiator was clogged and doing nothing. I know nobody wants to believe that it could be their radiator because it's so damn expensive but I would have to say pull the damn thing out. It's super easy.
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Paolo
Guest
like someone posted. install a mechanical temp gauge and run it into somewhere you can monitor it while driving. do everything you usualy do to bring the temp's up and see if the gauge temp. increases like the stock one. if it does then start to look for problems like rad etc. always try the simple things first
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Electro Gremlin
Guest
ptschram said:
PT --
What's a "CB" radiator? Is it Aluminum? If it works better than the stock unit and the price is right, I'm interested -- anything to keep the temp down.
---Norm