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Discussion Starter · #1 ·
So my car has neve ran hot in the 2 years I have owned it. Not when the ambient temp is say 85+ degrees if I sit idle for more than a few minutes, like today waiting on a buddy, the temp hand goes to 3/4 with the AC on. Once it reaches the 3/4 the a/c goes hot and the engine bogs for a few seconds then the A/C goes cold again like normal and the engine idles fine but temp hand is way up there at 3/4 still. This is the second time it has happened and it seems turning off the a/c makes it go away and cool back down. I have already drained and refilled the coolant and the thermostat seems to fuction perfect as far as giving heat in the morning only when it's warmed up and not like it is sticking closed or open.

I have been hearing about the CCRM that controls fan speed. I am not sure of an easy way to test it but I know it should be good as when I am flashing a tune with my tuner the fan comes on loud as hell. And it feels like it's blowing pretty damn good when it was running hot. I have smelt coolant on a few occasions but can find no leaks or loss of coolant in the bottle or anywhere else. Level seems to stay fine. I let the car run till normal temp with the cap off to try and get any bubbles out. When it over heated today I did notice some drops of coolant on the radiator plastic right around the cap. So I plan to replace the cap tonight and see if it goes away.

Any other ideas guys and gals? I need to fix it before temps hit 100+
 

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Discussion Starter · #2 ·
I should add I have noticed no over heating at hwy speed with a/c on
 

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If you bought the car used look for sediment on the bottom of the overflow tank cause someone might have put that sealant stuff in a while back and it might be cloggin you up somewere. The cap may be leaking but long shot. The reason I say this is the previous owner used that sealer fgor my radiator and it slowly started to get hotter and hotter so I changed the radiator and it went away. Hope I helped cause our cars are twins!
 

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Discussion Starter · #4 ·
I wil start with the cap lol. The car only had like 50k on it when I bought it :) Tank looks pretty good. Nice ride!
 

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I wil start with the cap lol. The car only had like 50k on it when I bought it :) Tank looks pretty good. Nice ride!
Ya start with the simple stuff! I wasnt trying to say replace your rad, I was just telling you my experience. Nice ride yourself I need to get a nice camera so I can take pics like your sig. Good luck with the fix though!
 

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Well at highway speeds even if your fans were not working you wouldn't over heat. You've got a lot of air hitting the fins of the radiator at those speeds.

A/C going hot do you mean your blower blows in hot air into the cabin before it bogs?
When its over heating have you popped your hood to see if the fans are running. If the engine temps get to a certain temp fans should switch on to cool the engine. If it doesn't I would think something is up with your temp sending unit. Usually when you turn on your A/C the fans kick on to ensure the extra load isn't creating more engine heat. If the fans aren't kicking on with the A/C on than there's an issue with wiring or the temp sensor.

I would say to wire your fans directly to the battery to see if its the fans but you say you can hear them when you install a tune. I would probably install a tune again and check if both fans are working.

You could always install a switch to the fan relay so that you manually turn them on or off when ever you choose. I had to do that to my Saturn when I had so it wouldn't over heat :)
 

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laser red representing
 

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Discussion Starter · #12 ·
LOl on all the MG love. I replaced cap and it's still overheating but taking longer to do so slightly. And yes, when the car bogs the A/C will blow hot air. And I only see one fan correct me if I am wrong. I just am not sure if I need to be looking at the fan or the CCRM that controls it and both look pricey so I am weary of throwing parts at it. I honestly can;t tell if the fan is going into the second speed or not. I know it's on but I think it may be running only in the lower speed and I don't know which part to replace first.
 

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Discussion Starter · #13 ·
Ok guys I jumped the red wire to the fan for low speed op and the fan came on connected directly to battery. I did the same with the blue/orange wire for high speed operation and the fan also came on. With the car running and at normal range on temp gauge with a/c on I tested both low and high speed wires going to the fan from ccrm (i guess) and both were showing 12 volts at the same time. Is this correct? If so it's telling me the ccrm and fan SHOULD be good. Perhaps my blower just makes to much heat under the hood in the hot ait with stock cooling system? I can only assume my thermostat is good or I would not be having normal heat correct? Also my hoses appear to be in good shape also.
 

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Discussion Starter · #14 ·
One other detail...back when it first over heated I topped off coolant and left the car running to normal temp with the radiator cap off. Coolant ended up starting to bubble all out with the cap off. Have since refilled coolant of course. I mean it bubbled alot. What is the proper way to bleed the air on these cars. I will probably replace thermostat this weekend.
 

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LOl on all the MG love. I replaced cap and it's still overheating but taking longer to do so slightly. And yes, when the car bogs the A/C will blow hot air. And I only see one fan correct me if I am wrong. I just am not sure if I need to be looking at the fan or the CCRM that controls it and both look pricey so I am weary of throwing parts at it. I honestly can;t tell if the fan is going into the second speed or not. I know it's on but I think it may be running only in the lower speed and I don't know which part to replace first.
I think you may be right its one fan I might be confusing with my other car. Anyway if your fans are working with a direct power source than its not your fans. Try replacing your thermostat or engine temp sensor it may not be working properly and its not sending a signal to fans to turn on. First of all have you checked if your fans kick on when A/C is on? If so then I would check the thermostat. Just start cheap and work your way up.


As for air in the system usually the reservoir tank is the "highest" point and air should find its way out of there but if your worried it might be air trapped in the system just run it with the cap off and lift and support the tank higher than the highest point of coolant lines which i think is the big one going from your radiator to the intake manifold or thermostat housing. here's an ok example of what kind of bubbles to look for


If you keep losing coolant while tracking this down, since you live in such a hot climate just run straight water its got almost twice the heat capacity of antifreeze, which will help help keep your car cooler. Water is one of the best liquids for absorbing and transferring heat.
 

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Discussion Starter · #17 ·
OK I am going to change the thermostat and flush out the radiator tmrw and put in yet more fresh coolant in a 50/50 mix. Any other ideas I am desperate. I still am not sure I can rule out the fan. Its hard to tell a difference between the low and high speed. If I jump the blue and orange wire from the fan this should in theory put it into high speed mode right?
 

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OK I am going to change the thermostat and flush out the radiator tmrw and put in yet more fresh coolant in a 50/50 mix. Any other ideas I am desperate. I still am not sure I can rule out the fan. Its hard to tell a difference between the low and high speed. If I jump the blue and orange wire from the fan this should in theory put it into high speed mode right?
I don't have a wiring diagram but if the blue/orange wire is what is indicated as high speed than yes. I don't think you need to flush your system again I think its just wasted money. But if you are try running straight water first and see how it aids in keeping the car cooler when the A/C is on. Water will keep your car cooler better than antifreeze and its free so its worth a shot.

I would imagine at low speed the fan wouldn't make as much noise as it would in high speed mode. At high speed it should be moving a good amount of air so it should be noticeable.

I re-read your post and I noticed you said while the A/C is running your getting 12V from low and high speed going to the fan at the same time? I'm no electronics expert but I would imagine that its a relay so it should only swap from one side to the other, also the CCRM distributes power to other components and relays but there is no relay for the electric fans so I'm assuming its withing the CCRM (correct me if I'm wrong). Just for kicks find a buddy with same year/model and swap out your CCRM for his see if it still does it. I know the CCRMs are very year and model specific. It may very well be that the fan is blowing at low speed when the A/C is on. If you cant find a friend are there any junk yards nearby? try finding one in there.

Just to be clear the engine does not overheat if the A/C is off correct? if this is true than I don't think a thermostat is going to make a difference. If it was the thermostat the car would overheat regardless.

If all else fails I would try the temp sensor on the crossover on the intake manifold.
 

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Discussion Starter · #20 ·
Sio you guys think that the ccrm could be bad if there is power on both the high speed and low speed wires? I don't have another to test with. As far as fan speed my blower and stuff is so loud that I can't hear the fan changing speeds.
 
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