Overheating interesting finding
#1
08-31-2010, 11:47 PM
Overheating interesting finding
I am in the middle of a trip across Australia and have now traveled 3000km in my much loved XJS. When in the middle of nowhere she decided to leak coolant from a pinhole in the LH return hose, very near the hose clamp (looks like a screwdriver impact). Anyway after waiting hours for our friendly local RAC guy to arrive to tape the hole so we could get to the next town. I have all sorts of tools with me spanners screwdrivers and sockets but NO tape, oh well.
He replaced the hose with one from a Ford, lucky it fitted. Now comes the interesting bit. After fitting the hose and filling the coolant (it only took about 5L) we were again under way. Now for the next few hundred KM the temp gauge crept up way higher than I was comfortable with. Which meant many stops to cool her down before continuing. I found that he had over filled the coolant and the pressure in the system was obviously so high that the thermostats could not open when the pressure rose. I evacuated some coolant from the system and viola we traveled 400km today with no temp issues.
The only thing I can put this down to is the new aftermarket radiator caps I installed prior to the trip. I should have vented the excess pressure. But these caps even though they are on the compatible list are obviously different.
He replaced the hose with one from a Ford, lucky it fitted. Now comes the interesting bit. After fitting the hose and filling the coolant (it only took about 5L) we were again under way. Now for the next few hundred KM the temp gauge crept up way higher than I was comfortable with. Which meant many stops to cool her down before continuing. I found that he had over filled the coolant and the pressure in the system was obviously so high that the thermostats could not open when the pressure rose. I evacuated some coolant from the system and viola we traveled 400km today with no temp issues.
The only thing I can put this down to is the new aftermarket radiator caps I installed prior to the trip. I should have vented the excess pressure. But these caps even though they are on the compatible list are obviously different.
#2
09-01-2010, 12:07 AM
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V12 XJS, I presume?
Was the system bled after the hose replaced?
AFAIK there's nothing unique about the caps. What psi rating were they? Should be 16psi.
Sometimes the hose to the atmospheric tank clogs, too...meaning the coolant has no place to go as it expands
Glad you made it home OK :-)
Cheers
DD
Was the system bled after the hose replaced?
AFAIK there's nothing unique about the caps. What psi rating were they? Should be 16psi.
Sometimes the hose to the atmospheric tank clogs, too...meaning the coolant has no place to go as it expands
Glad you made it home OK :-)
Cheers
DD
#3
09-01-2010, 02:06 AM
Yes 1989 V12
We didn't lose all of the coolant less than 1/4 no it wasn't bled as per the manual. I dont know what the psi rating of the caps are.. I will check the overflow pipe in the morning, I didn't think about that.
To correct the problem I opened the expansion tank cap to and released some of the coolant.
We still have 2500km to go before we get home so far she has performed perfectly even the 1500km trip across the desert.
cheers
We didn't lose all of the coolant less than 1/4 no it wasn't bled as per the manual. I dont know what the psi rating of the caps are.. I will check the overflow pipe in the morning, I didn't think about that.
To correct the problem I opened the expansion tank cap to and released some of the coolant.
We still have 2500km to go before we get home so far she has performed perfectly even the 1500km trip across the desert.
cheers
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