Loss of coolant + air con.

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C

cockneyjock

New Member
Posts
10
Location
Wiltshire UK
Hi all,

When I bought my 1995 P38 I was aware that the Air con was faulty and vowed to get it fixed 'soon'. Before Xmas I put her in for re-gassing and was told that I had a 'serious leak'. Now the weather is getting warmer and I am experiencing a problem.

I found the car overheating (on two occasions) and losing coolant. A 'jack of all trades' :blabla: has told me that the AC relies on the coolant to help it control itself and, as the AC has no gas, may well be causing the engine to overheat:confused:. Also, the AC system has to have oil in and, if the oil is lost, the AC circuit itself may be overheating.

Any comments would be greatly appreciated.

CJ.
 
as far as i am aware there is no coolant supply to the ac pump, suggest u get a sniff test done on your coolant system to rule out head gasket failure. my aircon has no gas in it and car dont overheat anymore (done head gaskets)
 
cockneyjock said:
Hi all,

When I bought my 1995 P38 I was aware that the Air con was faulty and vowed to get it fixed 'soon'. Before Xmas I put her in for re-gassing and was told that I had a 'serious leak'. Now the weather is getting warmer and I am experiencing a problem.

I found the car overheating (on two occasions) and losing coolant. A 'jack of all trades' :blabla: has told me that the AC relies on the coolant to help it control itself and, as the AC has no gas, may well be causing the engine to overheat:confused:. Also, the AC system has to have oil in and, if the oil is lost, the AC circuit itself may be overheating.

Any comments would be greatly appreciated.

CJ.
Click to expand...

In one word. BULL****.
True about oil in aircon but if there is no gas in, it cannot run, so cannot overheat.
 
Last edited:
I agree with Wammers, he's told you complete bollocks. As you said, 'jack of all trades' - sounds like master of none.

If there is no gas in the aircon then it will trip the switch for low pressure and won't run the compressor.

Not having the aircon on will actually slightly improve your cooling performance.

When the aircon is running it adds slight load to the engine turning the compressor, but the main effect on the cooling system comes from the fact that the aircon condenser is working and gets hot which heats the incoming air through the grille (as it's in front of the rad). So the result is that the air temp onto the coolant radiator is hotter, hence the coolant will then also be hotter.

Thats why the aircon is programmed to turn off at around 115 deg C coolant temperature in order to reduce the load on the cooling system if it's about to overheat.
 
Thanks Guys!

Just as I thought ... Bull****! :mad:

I will get a sniff test done on the cooling system as robp38 suggests and, I suppose, I must get the leak fixed in the AC. It just seems to be a big job to get the front of the car off to access it all.

Thanks again for the hep though.

CJ
 
I am a A/C commissioning engineer. The common problem with loss of of refrigerant in vehicles is due to the drying out of O rings and damaged condenser coil. The best way to test for leaks is to pressure test the system via the High pressure port with Oxygen Free Nitrogen to Approx 3 Bar with a Helium Trace gas added before you add the nitrogen. Then using soapy water solution check all pipe work joints and condenser core.
The A/C condenser is a common leaking component as it is located infront of the radiator thus can be damaged by road debris i e stones etc. The replacement of the P38 condenser is a very easy fix remove the front bumper and radiator grill panel remove the 2 refrigerant pipes for condenser core unclip electrical supply joints to condenser fans then unbolt the condenser Take condenser to bench or work top remove condenser fan assembly. New P38 Condenser approx £60.00 from ebay
Refit Condenser fan assembly and replace refrigerant pipe O rings then refit the Condenser. Evacuate system with Vacuum pump recharge system with 1450grams R134 refrigerant.
Refrigerant can be purchased in Halfords with oil and leak seal for £49.00 per 500grams with a £10.00 refund on each container.
The A/C Compressor on P38's are very reliable and generally only stop operating due to lack of refrigerant and cut out on the low pressure switch. There are 4 sensors interfaced with the HE-VAC unit
1. Outside Abient Sensor (Located under left hand side of front grill)
2. Vehicle Internal Solar Gain Sensor (Centre top dash nearest windscreen)
3. Evaporator Sensor (Located left hand side of heater access via Glove Box a twist and turn removal operation see Service Manual easy fix)
4. Suction Pipe Clip On Sensor (located on Suction Pipe right hand side of heater just clip off see Service Manual easy fix)
The 1st plan of attack would be to visit Quik Fit get a pressure test done find the leak.
If it is the Condenser buy a new one and you replace it
Take car back to Quik Fit get complete regas done this should sort out the A/C.
If the compressor starts Happy Days!
If you have a book symbol on the HE-Vac LCD display this could be a blend motor problem generally the centre blend motor unfortunately you have to buy a blend motor kit this is approx £220.00 and gives you 3 Blend motors.
Regarding sensors etc get a Test Book check done this will identify and sensor problems.
It is not the end of the world the A/C is a very easy fix :)

Best Regards
DavieP
 
Aircon condensor is the usual failure item on the P38. Dead easy to change, not too expensive either and a leak check and re-gas is around £50.
As others have said it's definately nothing to do with your overheating problem.
 
DavieP said:
I am a A/C commissioning engineer. The common problem with loss of of refrigerant in vehicles is due to the drying out of O rings and damaged condenser coil. The best way to test for leaks is to pressure test the system via the High pressure port with Oxygen Free Nitrogen to Approx 3 Bar with a Helium Trace gas added before you add the nitrogen. Then using soapy water solution check all pipe work joints and condenser core.
The A/C condenser is a common leaking component as it is located infront of the radiator thus can be damaged by road debris i e stones etc. The replacement of the P38 condenser is a very easy fix remove the front bumper and radiator grill panel remove the 2 refrigerant pipes for condenser core unclip electrical supply joints to condenser fans then unbolt the condenser Take condenser to bench or work top remove condenser fan assembly. New P38 Condenser approx £60.00 from ebay
Refit Condenser fan assembly and replace refrigerant pipe O rings then refit the Condenser. Evacuate system with Vacuum pump recharge system with 1450grams R134 refrigerant.
Refrigerant can be purchased in Halfords with oil and leak seal for £49.00 per 500grams with a £10.00 refund on each container.
The A/C Compressor on P38's are very reliable and generally only stop operating due to lack of refrigerant and cut out on the low pressure switch. There are 4 sensors interfaced with the HE-VAC unit
1. Outside Abient Sensor (Located under left hand side of front grill)
2. Vehicle Internal Solar Gain Sensor (Centre top dash nearest windscreen)
3. Evaporator Sensor (Located left hand side of heater access via Glove Box a twist and turn removal operation see Service Manual easy fix)
4. Suction Pipe Clip On Sensor (located on Suction Pipe right hand side of heater just clip off see Service Manual easy fix)
The 1st plan of attack would be to visit Quik Fit get a pressure test done find the leak.
If it is the Condenser buy a new one and you replace it
Take car back to Quik Fit get complete regas done this should sort out the A/C.
If the compressor starts Happy Days!
If you have a book symbol on the HE-Vac LCD display this could be a blend motor problem generally the centre blend motor unfortunately you have to buy a blend motor kit this is approx £220.00 and gives you 3 Blend motors.
Regarding sensors etc get a Test Book check done this will identify and sensor problems.
It is not the end of the world the A/C is a very easy fix :)

Best Regards
DavieP
Click to expand...

Excellent post. And your first one. Cheers for that and welcome aboard!
 
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