Leven Techs Cool Running Kit
Discussion
I'm thinking of trying the Mod-Wise Adjustable temp sensor kit on my 400SE.
The temp stays fine when running and when stationary.
My problem seems to arise when in traffic (ie. riding the cluch and reving up a bit but without really getting anywhere).
I've noticed that my fan kicks in at about 90 (normal I believe) but generally stays on for about 30-60 seconds and then goes off.
I've begun to think that this is because at such a slow speed (almost none) the water pump isn't really shifting much coolant. So the fan is not even cooling a full radiators worth of water. The fan quckly knocks off again since the otter switch is sat just above it basking in this little patch of cooler water.
My idea would be to position the temperature sensor on a hose as far away from the radiator as possible, ensuring the fan only cuts off when the overall coolant temperature has actually dropped and not just the bit in front of the fan.
Sorry to ramble.
Does this sound sensible or am I taking out of my arse?
The temp stays fine when running and when stationary.
My problem seems to arise when in traffic (ie. riding the cluch and reving up a bit but without really getting anywhere).
I've noticed that my fan kicks in at about 90 (normal I believe) but generally stays on for about 30-60 seconds and then goes off.
I've begun to think that this is because at such a slow speed (almost none) the water pump isn't really shifting much coolant. So the fan is not even cooling a full radiators worth of water. The fan quckly knocks off again since the otter switch is sat just above it basking in this little patch of cooler water.
My idea would be to position the temperature sensor on a hose as far away from the radiator as possible, ensuring the fan only cuts off when the overall coolant temperature has actually dropped and not just the bit in front of the fan.
Sorry to ramble.
Does this sound sensible or am I taking out of my arse?
Being not technical, I notice while driving no issue at all. Temp rises as soon as stationary traffic occurs. Fan comes in nicely and plenty of fluids. My conclusion: Fan is not up to the job, cold air is not sufficiently dragged through fan and/or hot air is not able to escape.
Someone suggested to get rid of rubber strip at the end of the hood (near front-window) in order to let the warm air escape better. Your view?
Do you have suggestions regarding improving fan cooling capacity, e.g. double fans, higher capacity fan, forcing cold air through radiator/fan etc.?
I had a look at the mod-wise two-stage cooling, but that postpones the problem of high temps IMHO. It does not increase the capacity, so in the end the result will be the same. Do you agree?
Thanks again,
Peter "Dutchperson" and V8S.
Rubber strip was the first thing to go! I've got a tripple core radiator and two of the biggest fans you can get. Like you, the problem only occurs when the car is stationary. When moving there is more than enough cooling, in fact the faster it goes the cooler it gets. The underlying problem is that the fans are sucking in hot air. Until you cure this the cooling system will never work properly while stationary. Once you fix this, the need for fan upgrades, two stage controllers and so on is greatly reduced although on mine with the increased heat output I would have them anyway.
Cheers,
Peter Humphries (and a green V8S)
bobfrance said: The fan quckly knocks off again since the otter switch is sat just above it basking in this little patch of cooler water.
Wherabouts is the otter switch on yours? (On mine the original otter switch was in the top hose; Griffiths and Chimaeras are in the swirl tank which is also in line with the top hose.)
Hmm, interesting.
The otter switch on mine sits in the top corner of the rad (well about 4" down from the top).
Off the top of my head I can't remember how near the relevant hoses are to it, although I think it may be better off not being in the rad at all.
That do you think?
Good point about the air recirculating BTW - I'll have to check mine out.
The otter switch on mine sits in the top corner of the rad (well about 4" down from the top).
Off the top of my head I can't remember how near the relevant hoses are to it, although I think it may be better off not being in the rad at all.
That do you think?
Good point about the air recirculating BTW - I'll have to check mine out.
GreenV8S said:
Rubber strip was the first thing to go! I've got a tripple core radiator and two of the biggest fans you can get. Like you, the problem only occurs when the car is stationary. When moving there is more than enough cooling, in fact the faster it goes the cooler it gets. The underlying problem is that the fans are sucking in hot air. Until you cure this the cooling system will never work properly while stationary. Once you fix this, the need for fan upgrades, two stage controllers and so on is greatly reduced although on mine with the increased heat output I would have them anyway.
So next to removing rubber strip a cure can be to prevent the fan sucking in hot air. Do I understand correctly that you will try this by moving the rad further to the front (if possible)? Any idea how you are going to manage that and do you have any other suggestions?
Thanks, Peter (V8S).
pgmvveld said:
So next to removing rubber strip a cure can be to prevent the fan sucking in hot air. Do I understand correctly that you will try this by moving the rad further to the front (if possible)? Any idea how you are going to manage that and do you have any other suggestions?
Thanks, Peter (V8S).
Removing the strip made only a very small improvement, and didn't cure the problem. I cured the problem by fitting a duct between the radiator and the front grill. This means that the fans have to draw air in from the front grill instead of just sucking in hot air round the sides of the radiator. To be fully effective I also had to blank off the rest of the grill not covered by the duct, because there was a significant amount of hot air leaking forward round the outside of the duct that was then being sucked into the front of the duct. (I still need to finish this off on the driver's side, the oil cooler makes this a bit more fiddly.)
Cheers,
Peter Humphries (and a green V8S)
bobfrance said: Hmm, interesting.
The otter switch on mine sits in the top corner of the rad (well about 4" down from the top).
Off the top of my head I can't remember how near the relevant hoses are to it, although I think it may be better off not being in the rad at all.
That do you think?
Good point about the air recirculating BTW - I'll have to check mine out.
The main thing Bob is that you have a 4xxSE wedge whose design is very different from that a Griff/Chimaera or V8S. The radis located in a pretty good sealed box with very good air circulation to start.
By all means fit the two speed switch but it turns out that the stat location is not bad in practice and simply using that is actually a good idea and less complicated.
Many of the 400s also have a major stat bypass externally - got the TVR details on this at the weekend - so the temp characteristics can be a little strange.
If you want better cooling then the first question to ask is why as the wedge nose cone arrangment is pretty effective providing everything is working. If you want better cooling because you are going to monster the engine, then fit an ally rad but be prepared for a lot of metalwork to re-attach the fans but that is the way to go. The 520 cooling system was deliberately over engineered so that I could control the temp easier by restricting air flow through the rad. It holds temp exceptionally well.
Steve
www.tvrbooks.co.uk
Hi Steve,
It's not that I want to monster the engine it's just that when I bought the car I replaced the radiator, hoses, fan and otter switch. I thought this would most likely solve my cooling problems; and by and large it has. But the car stll gets too hot when progressing slowly in traffic (summer or winter).
So it's this failiure to regulate it's temperature correctly I want to address.
If it's not a problem with the cooling system (shouldn't be , it's all new!) what could it be?
A slightly gone head gasket? I've not noticed any of the tell tale signs.
What do you think?
It's not that I want to monster the engine it's just that when I bought the car I replaced the radiator, hoses, fan and otter switch. I thought this would most likely solve my cooling problems; and by and large it has. But the car stll gets too hot when progressing slowly in traffic (summer or winter).
So it's this failiure to regulate it's temperature correctly I want to address.
If it's not a problem with the cooling system (shouldn't be , it's all new!) what could it be?
A slightly gone head gasket? I've not noticed any of the tell tale signs.
What do you think?
why does there appear to be several cubits or so of free/generous copper wire fallangulating around the place? Bob what is hot? 90+ in traffic on a hot day is not overheating but normal.
Have you checked the guage? They can read 5,10,15 degrees high.
Have you fitted the correct TVR spec stat and bits and pieces? The Range Rover ones are the wrong types with incorrect specs and lead to overheating.
What temp do the fans come on?
If it was a heat gasket you would have mayo in the oil or loosing water like a good one!
Have you checked the guage? They can read 5,10,15 degrees high.
Have you fitted the correct TVR spec stat and bits and pieces? The Range Rover ones are the wrong types with incorrect specs and lead to overheating.
What temp do the fans come on?
If it was a heat gasket you would have mayo in the oil or loosing water like a good one!
shpub said:If it was a heat gasket you would have mayo in the oil or loosing water like a good one!
What if it was a very small hole?
Anyway. The thermostat opens in the mid 80's, my fan trips in about 90 and the guage goes into the red at about 100 although the needle can often be seen midway on the red
(I always stop before it gets any further). The sight of coolant boiling in the expansion tank tells me the guage is reading fairly accurately. (new cap fitted with the correct rating)
My mind keeps drifting back to the worry that the cooling fan kicking in at about 90 and the temp redlining at about 100 leaves a very narrow temperature band to operate in and not a lot of margin for error.
Since the fan has no form of delay on it (acting as a buffer to keep it running)it is hunting ie. not staying on long enough to properly cool the body of liquid runing through the cooling system. Leaving me with a fan that smeems to click on and off too regularly.
Any thoughts Steve?
bobfrance said:
Anyway. The thermostat opens in the mid 80's, my fan trips in about 90 and the guage goes into the red at about 100 although the needle can often be seen midway on the red
The sight of coolant boiling in the expansion tank tells me the guage is reading fairly accurately. (new cap fitted with the correct rating)
My mind keeps drifting back to the worry that the cooling fan kicking in at about 90 and the temp redlining at about 100 leaves a very narrow temperature band to operate in and not a lot of margin for error.
Since the fan has no form of delay on it (acting as a buffer to keep it running)it is hunting ie. not staying on long enough to properly cool the body of liquid runing through the cooling system. Leaving me with a fan that smeems to click on and off too regularly.
Any thoughts Steve?
Some random thoughts in no particular order ...
Those temperatures all sound a little on the high side but not totally out of order. Are you saying that the gauge goes into the red and it starts to boil while the fans are still cycling on and off? That's definitely a problem, either with the otter switch or the water circulation. It's worth being clear whether this is the case, because it's very unusual and most of the common cooling system problems don't produce this behaviour. I'll assume this is the case, for now.
If it's under pressure, the boiling point should be up around 110 C. Is it possible the gauge is under-reading slightly?
Has the cooling system has ever worked properly? If so, did the current behaviour start suddenly or did it come on gradually? Was any work done on the cooling system around the time it started?
I assume your otter switch is on the conventional place, i.e. on the side of the radiator, close to the top hose. (The top hose is the one that comes from the thermostat housing, high up on the front of the engine.)
There is a hysteresis of a couple of degrees on the otter switch so it would be unusual for the fans to switch off sooner than 30 seconds or so. If they're switching off very quickly, I would suspect a faulty otter switch or fan relay.
The otter switch on the top hose responds very slowly to changes in radiator temperature and I'd expect it to stay on even longer than that.
If your cooling system has been altered (I believe the correct technical term is "messed about"!) you may find the otter switch is the wrong rating hence turning the fans on too late. I understand there's a Range Rover aircon otter switch which comes in about 15 degrees too high, which is sometimes fitted by mistake. Allow a few degrees of error here and there and this *could* be the problem you're seeing. If the plumbing has been altered so that the otter switch is in the bottom hose (not likely IMO, but don't rule it out) then the otter switch would need to be changed for one with about a 10 degree lower rating, because the lower hose is about 8 degrees cooler than the top hose. (Technically speaking, the bottom hose is a better place for the switch, but you do need to change the temp rating if you move it there.) Clutching at straws, and I can't think this is at all likely, but you can get left- and right-handed water pumps; if yours has somehow got swapped over then you would have some pretty strange behaviour including an otter switch which is effectively in the bottom hose (see below).
If the otter switch is working properly and the radiator is being cooled properly by the fans, and the engine still overheats, the most likely explanation is a weeping head gasket. Another possible cause is a faulty water pump (or wrong size pulley on a good pump) causing too little water flow. Since the bypass is not closed by the stat on those models, at hot tickover a significant proportion of water goes via the bypass and doesn't see the radiator at all. Combine this with poor water flow and the radiator may not get enough water flow to cool the engine. This problem is more likely to cause those symptoms if the otter switch is in the bottom hose, since it will regulate the return water temperature to (say) 80 degrees but may not have enough mass flow to keep the engine temperature below boiling point with that return temperature.
Hope you can make some sense of this, if you can confirm the symptoms I'll try to have another think over the weekend.
Now, shall I go fight my way through the christmas shoppers or get some of those jobs done on the car?
:getsswarfegaout:
Cheers,
Peter Humphries (and a green V8S)
Are you saying that the gauge goes into the red and it starts to boil while the fans are still cycling on and off?
When it starts to boil (about 110 according to the guage) The fans remain on. But for obvious reasons I've never kept the engine running to see if the fan manages to cool it.
If it's under pressure, the boiling point should be up around 110 C. Is it possible the gauge is under-reading slightly?
It appears to be within a reasonable tolerance.
Has the cooling system has ever worked properly?
No, When I bought the car the Rad was knackered.
I have since replaced the rad, hoses, both caps, hoses & otter switch.
I assume your otter switch is on the conventional place, i.e. on the side of the radiator, close to the top hose. (The top hose is the one that comes from the thermostat housing, high up on the front of the engine.)
It is.
There is a hysteresis of a couple of degrees on the otter switch so it would be unusual for the fans to switch off sooner than 30 seconds or so. If they're switching off very quickly, I would suspect a faulty otter switch or fan relay.
The otter switch on the top hose responds very slowly to changes in radiator temperature and I'd expect it to stay on even longer than that.
The otter was new from HHC. But old one behaved in exactly the same way too.
...you can get left- and right-handed water pumps; if yours has somehow got swapped over then you would have some pretty strange behaviour including an otter switch which is effectively in the bottom hose (see below).
interesting point - how do I check it?
If the otter switch is working properly and the radiator is being cooled properly by the fans, and the engine still overheats, the most likely explanation is a weeping head gasket.
I'm still wondering about this one but I've had a pressure test done and as far as we can tell it's okay.
It doesn't overheat when driven hard. to me this suggeststhat it's possibly not a head gasket problem.
Another possible cause is a faulty water pump (or wrong size pulley on a good pump) causing too little water flow. Since the bypass is not closed by the stat on those models, at hot tickover a significant proportion of water goes via the bypass and doesn't see the radiator at all. Combine this with poor water flow and the radiator may not get enough water flow to cool the engine. This problem is more likely to cause those symptoms if the otter switch is in the bottom hose, since it will regulate the return water temperature to (say) 80 degrees but may not have enough mass flow to keep the engine temperature below boiling point with that return temperature.
Yeah, I've been wondering about the pump too.
Cheers Peter. hope you made the right choice over the shopping! ;O)
I would check that the temp guage is accurate for a start. Not unknown for these to be inaccurate. Your 100 could be 95 in which case the system appears to be normal.
Fans switching in and out is normal. They should stay on for a minute of so as it all depends on how much heat they have to remove. they is quite a bit of hysteresis with these but the stat position does assume that there are no air locks in the rad as the air pocket can collect where the stat is. A duff relay could be at fault as well. Chcek and see if the otter switch ios off when the fans turn off. If not there is a relay/wiring problem. If it is a wiring problem, this could reduce the current and the fan speed. BTW Guys all this is for a Wedge not a Chimaera. Different car.... different location... different characteristics.
As for pinholes in gaskets.... they tend not to be pinholes for long. A carbon test can be done on the coolent to see if there is a problem. Frosts sell the kit for around £20 if you want to do it.
As for LH and RH pumps, tis true but they are not interchangeable so unless the engine has been changed I would not worry about that.
I would also make sure that the fans are connected in the right way, blowing air through the rad into the engine bay.
Which fans did you fit as it is also possible thay are simply not upto the job. Many of the aftermarket ones move air not not fast enough. I use a couple of Cerbera ones on the 520.
Could be the wrong water pump or this is dieing. Usually they start weeping below the pulley axle. Tis possible that this has died or that there is some blockage. They normally come with no pulley so unless the car has had this problem throughout its life, the pulley size should not be an issue.
Bob: I suggest carrying on in the Wedge section. I can see many Chimaera owners getting very very confused and starting to complain....
Steve
www.tvrbooks.co.uk
>> Edited by shpub on Sunday 1st December 08:55
Fans switching in and out is normal. They should stay on for a minute of so as it all depends on how much heat they have to remove. they is quite a bit of hysteresis with these but the stat position does assume that there are no air locks in the rad as the air pocket can collect where the stat is. A duff relay could be at fault as well. Chcek and see if the otter switch ios off when the fans turn off. If not there is a relay/wiring problem. If it is a wiring problem, this could reduce the current and the fan speed. BTW Guys all this is for a Wedge not a Chimaera. Different car.... different location... different characteristics.
As for pinholes in gaskets.... they tend not to be pinholes for long. A carbon test can be done on the coolent to see if there is a problem. Frosts sell the kit for around £20 if you want to do it.
As for LH and RH pumps, tis true but they are not interchangeable so unless the engine has been changed I would not worry about that.
I would also make sure that the fans are connected in the right way, blowing air through the rad into the engine bay.
Which fans did you fit as it is also possible thay are simply not upto the job. Many of the aftermarket ones move air not not fast enough. I use a couple of Cerbera ones on the 520.
Could be the wrong water pump or this is dieing. Usually they start weeping below the pulley axle. Tis possible that this has died or that there is some blockage. They normally come with no pulley so unless the car has had this problem throughout its life, the pulley size should not be an issue.
Bob: I suggest carrying on in the Wedge section. I can see many Chimaera owners getting very very confused and starting to complain....
Steve
www.tvrbooks.co.uk
>> Edited by shpub on Sunday 1st December 08:55
You're right Steve, I know what those Chimaera owners can be like!
(I'm joking!)
I've started a new thread here..
www.pistonheads.net/gassing/topic.asp?t=23206&f=12&h=0
(I'm joking!) I've started a new thread here..
www.pistonheads.net/gassing/topic.asp?t=23206&f=12&h=0
I know the thread has changed somewhat but, is it recommended to reduce the "minimum" running temperature by fitting a lower water thermostat as in Sprint magazine? Forget the otter as even if you keep the fans running from start up, the engine will get up to the "minimum" temp if you move from the drive. You may be able to keep the temp to 72 at tick over but i would say that even if you remove the water stat completely, in the spring or summer the engine wants to run at atleast 85-87 depending on throttle. The lower water stat will only give a lower running temp in the winter, precisely when you dont need it! Fit a lower otter by all means. Have some cooling effect after the fans have gone off, just like the "Rangie" ,origin,that has a full time fan. The newer TVR have 2 stage cooling!
TVR fit either an 82 or a 78 degree stat which has bigger orifices and occassionally two or three small holes to provide bleed through. These are often referred to as the lower temp stats as opposed to the rover ones which are 88 or even 92!
This allows water to pass through to the rad and get an increased cooling effect at a lower temp and thus gives a bit more time to provide the correct thermo dynamic balance. Stat temps and otter temps work to provide this balance as there is a large time effect as heat is trandsferred. Nothing is instantaneous.
If the stat does not open early enough, there is not enough time to remove sufficient heat to cool the car down before it boils over/overheats etc. In this case a bigger rad is needed with more capacity to reduce the time taken to dissapate the amount heat needed to cool the car.
Playing with stats and otter switches is more to do with changing the thermodynamic balance than temperatures.
The stat will only control the temp when the temp is near its opening temp. below that it stays shut and does nothing and above it it is open and does nothing.
Fitting a lower temp stat alters the thermodynamics of the system so that the balance is reached earlier without risking thermal overload. Same idea as the famous two speed fans that start the cooling a little bit earlier so that the car temp doesn't change much.
>> Edited by shpub on Monday 2nd December 08:53
This allows water to pass through to the rad and get an increased cooling effect at a lower temp and thus gives a bit more time to provide the correct thermo dynamic balance. Stat temps and otter temps work to provide this balance as there is a large time effect as heat is trandsferred. Nothing is instantaneous.
If the stat does not open early enough, there is not enough time to remove sufficient heat to cool the car down before it boils over/overheats etc. In this case a bigger rad is needed with more capacity to reduce the time taken to dissapate the amount heat needed to cool the car.
Playing with stats and otter switches is more to do with changing the thermodynamic balance than temperatures.
The stat will only control the temp when the temp is near its opening temp. below that it stays shut and does nothing and above it it is open and does nothing.
Fitting a lower temp stat alters the thermodynamics of the system so that the balance is reached earlier without risking thermal overload. Same idea as the famous two speed fans that start the cooling a little bit earlier so that the car temp doesn't change much.
>> Edited by shpub on Monday 2nd December 08:53
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