Thermostat or water pump?
Discussion
Hello
The old cooling problems which come more critical as the weather gets hotter!
I have a 94 pre serpentine chim which is running really hot
. I have checked the usal things like correct water level, air pockets in the radiater, fan belt tension. the two electric fans working etc.
so must be one of two things I think:
1.Thermosat jammed closed or near to closed
2.Water pump is defective, probably the bearings.
So:
1. Where is the thermosat? is it easy to remove? Then I can test it and see if thats the problem.
2. How can you test the water pump without removing it (I can take the fan belt off easily if this helps).
If anybody can help it would be much appreciated so I can enjoy the nice weather. Its not in the SH bibel see
!
Thanks
The old cooling problems which come more critical as the weather gets hotter!
I have a 94 pre serpentine chim which is running really hot

so must be one of two things I think:
1.Thermosat jammed closed or near to closed
2.Water pump is defective, probably the bearings.
So:
1. Where is the thermosat? is it easy to remove? Then I can test it and see if thats the problem.
2. How can you test the water pump without removing it (I can take the fan belt off easily if this helps).
If anybody can help it would be much appreciated so I can enjoy the nice weather. Its not in the SH bibel see

Thanks
zippy
Took it out last night and just gentle 50 - 60 mph in top was producing 92 - 100! Too hot I think, I was having to use the cockpit heater to take heat off the engine. I took the bleed nut off the radiator and no air cane out just a mix of water and anti-freeze. The fans are working fine, I have even hardwired them so they are on from the moment the ignition is turned, and the car is still running hot. At tick over the turning over of the belt is not super quiet. but this is hard to tell.
Took it out last night and just gentle 50 - 60 mph in top was producing 92 - 100! Too hot I think, I was having to use the cockpit heater to take heat off the engine. I took the bleed nut off the radiator and no air cane out just a mix of water and anti-freeze. The fans are working fine, I have even hardwired them so they are on from the moment the ignition is turned, and the car is still running hot. At tick over the turning over of the belt is not super quiet. but this is hard to tell.
Thanks zippy and quinny
I don't think that its the temp gauge since when you pull the bonnet up after a run its running so much hotter than it ever use to. I will remove and test the thermostat and see if its that, and I will test the water pump by hand with the belt off and see if its ok when I get home tonight. Will let you know the result
Thanks guys
I don't think that its the temp gauge since when you pull the bonnet up after a run its running so much hotter than it ever use to. I will remove and test the thermostat and see if its that, and I will test the water pump by hand with the belt off and see if its ok when I get home tonight. Will let you know the result
Thanks guys
Alex,
I don't think the rad is the best place to bleed the system, it's too low.
The best practise seems to be to put the car facing up a hill, open the swirl pot (MAKE SURE IT'S COLD! and don't open the expansion chamber cap), run the engine, and keep the swirl chamber topped up until the fans have kicked in a couple of times. Then refit the cap.
That should clear any airlocks.
Also, if the thermostat isn't opening then the rad should not get hot, the fans won't run etc etc. Check that too.
Jon
>> Edited by xain on Friday 17th May 16:25
I don't think the rad is the best place to bleed the system, it's too low.
The best practise seems to be to put the car facing up a hill, open the swirl pot (MAKE SURE IT'S COLD! and don't open the expansion chamber cap), run the engine, and keep the swirl chamber topped up until the fans have kicked in a couple of times. Then refit the cap.
That should clear any airlocks.
Also, if the thermostat isn't opening then the rad should not get hot, the fans won't run etc etc. Check that too.
Jon
>> Edited by xain on Friday 17th May 16:25
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