Odd overheating
#1
Odd overheating
Heya folks. Having issues with my 4.0 v8 1999 s Type.
I noticed yesterday there was no heat coming from the blowers (tried all different settings) and then within less than 5 minutes the car started overheating and ‘high engine temperature’ was displayed on the dash.
Over the course of last year it’s had a new DCCV , thermostat, expansion bottle, radiator, temperature sensor & upgraded aluminium thermostat housing
Am I right in saying this could be waterpump related as the car has done 133,000 miles and I believe it’s still on the original water pump and the plastic impellers have worn off over time. Any help or inputs would be appreciated.
I noticed yesterday there was no heat coming from the blowers (tried all different settings) and then within less than 5 minutes the car started overheating and ‘high engine temperature’ was displayed on the dash.
Over the course of last year it’s had a new DCCV , thermostat, expansion bottle, radiator, temperature sensor & upgraded aluminium thermostat housing
Am I right in saying this could be waterpump related as the car has done 133,000 miles and I believe it’s still on the original water pump and the plastic impellers have worn off over time. Any help or inputs would be appreciated.
Last edited by Stanners; 02-18-2018 at 11:16 AM. Reason: Missed information out
#2
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Location: Newport Beach, California
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#4
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#5
+1 on that.
Before convincing myself of one theory (worn water pump impeller), I'd highly suggest running some basic diagnostics.
Hook up a cooling system pressure tester. This the thing that looks like a bicycle pump with a gauge, and connects in place of the reservoir cap. You pump up the cooling system to the specified pressure and make sure the pressure holds. You also look for leaks. On my '02 V6, I've noticed cooling system behavior is very finicky if the pressure can't build up to normal. Heater performance drops off, which you've already experienced. What I found was a small leak near the reservoir, but because of the location, mostly air was escaping, with very little coolant loss. The symptoms were low heat and the coolant temp gauge above normal, although no actual overheat. No idea if this is your issue, but it's worth investigating. Some parts stores offer free loaner tools if you don't want to buy a pressure tester.
The other recommendation is to check coolant line temperatures with an infrared thermometer. A cheap one will set you back maybe $15. Keep a close eye on the car's temp gauge, and quickly check the coolant temps before and after the thermostat, and at the radiator inlet, too.
I'd check the serpentine belt tension, too. A slipping belt could cause your symptoms.
Also, when you said the car "started overheating", exactly what happened? Did you see steam venting under the hood? I'm wondering if you only had an indication problem, not an actual overheat. That wouldn't explain the lack of heat, though, but is still something to consider.
#6
+1 on that.
Before convincing myself of one theory (worn water pump impeller), I'd highly suggest running some basic diagnostics.
Hook up a cooling system pressure tester. This the thing that looks like a bicycle pump with a gauge, and connects in place of the reservoir cap. You pump up the cooling system to the specified pressure and make sure the pressure holds. You also look for leaks. On my '02 V6, I've noticed cooling system behavior is very finicky if the pressure can't build up to normal. Heater performance drops off, which you've already experienced. What I found was a small leak near the reservoir, but because of the location, mostly air was escaping, with very little coolant loss. The symptoms were low heat and the coolant temp gauge above normal, although no actual overheat. No idea if this is your issue, but it's worth investigating. Some parts stores offer free loaner tools if you don't want to buy a pressure tester.
The other recommendation is to check coolant line temperatures with an infrared thermometer. A cheap one will set you back maybe $15. Keep a close eye on the car's temp gauge, and quickly check the coolant temps before and after the thermostat, and at the radiator inlet, too.
I'd check the serpentine belt tension, too. A slipping belt could cause your symptoms.
Also, when you said the car "started overheating", exactly what happened? Did you see steam venting under the hood? I'm wondering if you only had an indication problem, not an actual overheat. That wouldn't explain the lack of heat, though, but is still something to consider.
Before convincing myself of one theory (worn water pump impeller), I'd highly suggest running some basic diagnostics.
Hook up a cooling system pressure tester. This the thing that looks like a bicycle pump with a gauge, and connects in place of the reservoir cap. You pump up the cooling system to the specified pressure and make sure the pressure holds. You also look for leaks. On my '02 V6, I've noticed cooling system behavior is very finicky if the pressure can't build up to normal. Heater performance drops off, which you've already experienced. What I found was a small leak near the reservoir, but because of the location, mostly air was escaping, with very little coolant loss. The symptoms were low heat and the coolant temp gauge above normal, although no actual overheat. No idea if this is your issue, but it's worth investigating. Some parts stores offer free loaner tools if you don't want to buy a pressure tester.
The other recommendation is to check coolant line temperatures with an infrared thermometer. A cheap one will set you back maybe $15. Keep a close eye on the car's temp gauge, and quickly check the coolant temps before and after the thermostat, and at the radiator inlet, too.
I'd check the serpentine belt tension, too. A slipping belt could cause your symptoms.
Also, when you said the car "started overheating", exactly what happened? Did you see steam venting under the hood? I'm wondering if you only had an indication problem, not an actual overheat. That wouldn't explain the lack of heat, though, but is still something to consider.
#7
It's perfectly normal for the pipes to feel hard. What is normal pressure, isn't it 13 or 16 psi? That's a lot of pressure. If the pressure exceeded limits, the cap should have vented. Have the cap tested, too, just to be safe.
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#8
Maybe not common, but certainly not rare. See post #16 in my tale of woe, involving a new thermostat AND a new temperature sensor both bad from stock:
https://www.jaguarforums.com/forum/s...rature-186873/
https://www.jaguarforums.com/forum/s...rature-186873/
#9
Maybe not common, but certainly not rare. See post #16 in my tale of woe, involving a new thermostat AND a new temperature sensor both bad from stock:
https://www.jaguarforums.com/forum/s...rature-186873/
https://www.jaguarforums.com/forum/s...rature-186873/
#10
cheers for the reply! Either way for the sake of Ł35 I’d rather myself a new water pump for peace of mind, saves a lot of hassle in the future. I’ll have the system pressure checked some time and check for leaks, my freind has one of these. As for the last comment. The pipes were rock hard and almost bulging. The fan kicked in aggressively and the temp gauge was through the roof. But it could of been a misjudgement of error within the system and not actually overheating. Is it common for new thermostats to stick closed sometimes?
I heard if you install it backwards it will not open. Of coarse I have never done this but I heard it is possible
#11
Re: "swaying towards a stuck thermostat". Be careful, don't just guess, but take some time for diagnosis. Originally you had yourself convinced the water pump was bad, but now the wind has changed direction and you're leaning towards a thermostat.
I'll admit I'm as guilty as the next guy, as if a part is inexpensive and easy to access, I'll usually just try it first and see what happens. But for something more involved, such as the water pump, I'd want to be positive before digging in too deep. The thermostat? Easier to change, but you'd still get your hands dirty, possibly for no good reason. Before digging in, pick up an inexpensive infrared thermometer and see what is really happening. You still don't know if you've got an actual overheat or just an indication issue. Or as in my recent foibles, a combination of both.
#13
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If you decide to replace the thermostat, you should also change the water outlet as well since they can only endure a finite number of cold/hot cycles before failing. The thermostat 'tower' is also made of plastic, but there is an aluminium version available from the aftermarket suppliers such as S.N.G. Barratt.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
#14
#15
#16
If you decide to replace the thermostat, you should also change the water outlet as well since they can only endure a finite number of cold/hot cycles before failing. The thermostat 'tower' is also made of plastic, but there is an aluminium version available from the aftermarket suppliers such as S.N.G. Barratt.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
#17
#18
If you decide to replace the thermostat, you should also change the water outlet as well since they can only endure a finite number of cold/hot cycles before failing. The thermostat 'tower' is also made of plastic, but there is an aluminium version available from the aftermarket suppliers such as S.N.G. Barratt.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
The water pump is relatively simple to replace once the water outlet is removed and the hoses out of the way.
#19
[/left]
Only the '99-'02 V6 engines had the CHT sensor. Your V8 has a conventional coolant temperature sensor, only one I think.
Re: "swaying towards a stuck thermostat". Be careful, don't just guess, but take some time for diagnosis. Originally you had yourself convinced the water pump was bad, but now the wind has changed direction and you're leaning towards a thermostat.
I'll admit I'm as guilty as the next guy, as if a part is inexpensive and easy to access, I'll usually just try it first and see what happens. But for something more involved, such as the water pump, I'd want to be positive before digging in too deep. The thermostat? Easier to change, but you'd still get your hands dirty, possibly for no good reason. Before digging in, pick up an inexpensive infrared thermometer and see what is really happening. You still don't know if you've got an actual overheat or just an indication issue. Or as in my recent foibles, a combination of both.
Only the '99-'02 V6 engines had the CHT sensor. Your V8 has a conventional coolant temperature sensor, only one I think.
Re: "swaying towards a stuck thermostat". Be careful, don't just guess, but take some time for diagnosis. Originally you had yourself convinced the water pump was bad, but now the wind has changed direction and you're leaning towards a thermostat.
I'll admit I'm as guilty as the next guy, as if a part is inexpensive and easy to access, I'll usually just try it first and see what happens. But for something more involved, such as the water pump, I'd want to be positive before digging in too deep. The thermostat? Easier to change, but you'd still get your hands dirty, possibly for no good reason. Before digging in, pick up an inexpensive infrared thermometer and see what is really happening. You still don't know if you've got an actual overheat or just an indication issue. Or as in my recent foibles, a combination of both.
#20
Worth checking.
You won't have a heating issue if the engine is written off...
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