Once off overheating

[losh1971]

Thanks Wozza I reckon i will grab a couple of fans from the wreckers over the next few weeks. I guess I will just have to keep an eye on it and be prepared if it overheats again.

 

[losh1971]

Well it looks like the massive pressure in the cooling system has stuffed my 5-6 month old water pump. Is massive pressure even a cause of water pump failure??

 

[losh1971]

Quick update, I just pulled the relay and noticed it has some melting at the base of the #30 post. Should I upgrade and fit a 40a or is just the relay is old? I have also warmed up the engine and am going to cool it down and see if the pump is still weeping, once the engine is cool.

 

[Wozza]

Pin 30 is the 12v from battery, if there is melting its because its pulling to much current or there is corrosion causing high resistance.....
check that the fuse is right amperage clean up the contacts and see how it go's with new relay(could also be the fan motor pulling to much current)...Ive had a water pump fail just after a major overheat..but no idea how old it was though..

 

[losh1971]

Thanks Wozza. I will do as you suggested when fitting the new relay. If I need a new pump I am arseing the GMB and going Gates. Because GMB seem to have gone downhill in recent years.

 

[EYY]

GMB is a good brand. How has your water pump failed? Cooling system pressure is regulated by the radiator cap, so should never see over 15psi.

Contrary to popular belief, even cruising at 100kmph the fan will often need to come on in temps as low as 20 degrees I’ve found. This is a problem pretty well applicable to thermo fans. A poorly performing clutch fan will still move enough air at speed - and I assume this is why people try to diagnose their cooling problems by assessing the temperature at highway speeds. This is compounded with new cars having even more obstacles for ram air to flow around.

When the fuse blew for my thermo fan over a year ago, the temp shot up above 3/4 very quickly driving on level highway roads at 100kmph. A properly functioning fan is necessary in all road conditions - not just some

Pull your old relay apart and see whether the contacts look burnt/charred. Will be obvious if it’s damaged. A more likely cause would be a coolant leak - have you checked all hoses/clamps/heater tap/heater core?

 

[losh1971]

GMB is a good brand. How has your water pump failed? Cooling system pressure is regulated by the radiator cap, so should never see over 15psi.

Contrary to popular belief, even cruising at 100kmph the fan will often need to come on in temps as low as 20 degrees I’ve found. This is a problem pretty well applicable to thermo fans. A poorly performing clutch fan will still move enough air at speed - and I assume this is why people try to diagnose their cooling problems by assessing the temperature at highway speeds. This is compounded with new cars having even more obstacles for ram air to flow around.

When the fuse blew for my thermo fan over a year ago, the temp shot up above 3/4 very quickly driving on level highway roads at 100kmph. A properly functioning fan is necessary in all road conditions - not just some

Pull your old relay apart and see whether the contacts look burnt/charred. Will be obvious if it’s damaged. A more likely cause would be a coolant leak - have you checked all hoses/clamps/heater tap/heater core?

Pump had a drip underneath which was only evident when I pulled the bonnet after the engine boiled. I am currently waiting the 6 hours for the engine temp to drop to atmospheric temp before I can say for sure the pump has failed. It could be the gasket but all parts need to equalise before I can say for sure. Or it may just have been enough pressure to squeeze past the seal and under normal pressure it won't necessarily occur again. I replaced a six month old GMB with another GMB because it was leaking out the weep hole. I thought GMB were good too but it seems they may have dropped their standards in recent years. I have used them in the past and only on the VR have I had a GMB leak.
Up until the tiny drip from underneath the pump I have no leaks as I fixed them all over a period of about three months; due to failure of different components each time one part was replaced or repaired. Although having said that I wouldn't be surprised if I now have a heater core leak, due to the excess pressure placed on the system yesterday.
Cap is a 20/135 which is the right cap. Having said that I would like to drop the cap pressure to the next one down if one is available.

 

[losh1971]

Pull your old relay apart and see whether the contacts look burnt/charred. Will be obvious if it’s damaged. A more likely cause would be a coolant leak - have you checked all hoses/clamps/heater tap/heater core?

Relay has some melting around post 30 as well as some evidence of arching definitely an electrical problem somewhere. I'd like to see if the wreckers have a front and rear thermo fan. Because if the issue happens again I am thinking possibly the hit that the front fan has taken at some point has caused some damage other than just cosmetic. Although I would have thought the fuse would blow first??

I know relays do fail over time so maybe that was all it was. Maybe 12 months of frequent use has been enough for it to finally fail.

It's not a major issue but the once a week, 1.5hr trip each way, without mob reception is my main concern.

 

[losh1971]

Checked all the fuses including the major fuses under the bonnet and all were the correct rating. Only one exception and that was a 10a in the main fuse panel under the wheel that would normally be a 7.5a.

 

[EYY]

Use the recommended cap otherwise you’ll keep boiling it. Increased pressure increases the boiling temp.


That weep won’t be a result of the overheating, it’ll be the cause.