Boyracer said:Hey Pottsy,
Just one observation. My car had a 4lb radiator cap in it when I first got the car.
I was advised to swap it for a 7lb one. Can't remember why.
And who has been having probs with a leaking water pump
DS Cooling
- Thread starter pottsy
- Start date
And who has been having probs with a leaking water pump
Mr Citroen got it right...
pottsy, I think you are doing all the right things and will get the result you seek
When I first purched my current D, I had similar symptoms, rodded the radiator = small improvement, new water pump = small improvement. Someone had at some stage prior to my ownership tried an electric fan bolted to the radiator and must have decided it was not to be the solution (I can see the evidence).
The cure for my car was to get the vinyl shroud remade as recommended by Ian Reddiex of Euroserve, (mine was in very poor condition with big rips and tears). Car now has no problems here in Queensland summer even crawling through city traffic.
The design of the scoop and shroud must be spot on - and quite critical for efficient cooling, the zippered section though quite small must be just the right opening for use in extreme cold situations.
Cheers
Chris
pottsy, I think you are doing all the right things and will get the result you seek
When I first purched my current D, I had similar symptoms, rodded the radiator = small improvement, new water pump = small improvement. Someone had at some stage prior to my ownership tried an electric fan bolted to the radiator and must have decided it was not to be the solution (I can see the evidence).
The cure for my car was to get the vinyl shroud remade as recommended by Ian Reddiex of Euroserve, (mine was in very poor condition with big rips and tears). Car now has no problems here in Queensland summer even crawling through city traffic.
The design of the scoop and shroud must be spot on - and quite critical for efficient cooling, the zippered section though quite small must be just the right opening for use in extreme cold situations.
Cheers
Chris
The intent of the zipper is to enable it to be opened if the car is travelling through snow as the lower intake could get blocked and therefore prevent any air intake which might ironically lead to an overheated engine in winter. Just the thing for a winter excursion to Toowoomba (GB) or to the ski fields (Pottsy), or anywhere in Tassie in winter...
UFO said:
And to clean the build up of crud stuck to the core.
UFO said:
Snow :roflmao: :roflmao: I wish...
no reason to unzip my zipper then Craig (keep it above the belt, this is a family forum...)
Cheers
Chris
pottsy said:
Pottsy,
maybe I'm missing something here but does your car actually has an overheating problem anymore, now that you've gone over it thoroughly?
You mentioned above, that when the electric fan cuts in it will bring the coolant temperature back down. Then it will slowly build up until the fan trips and lowers it again... If Reynolds comments (in my original post) are correct - and I noticed that 'DS' tends to agree with him on this point - whenever your electric fan is idle the car has virtually nil airflow through the radiator. So you'd be surprised if the temp didn't rise; even the best cooling system needs airflow via some means. Now I agree that cooling on these cars is marginal; but Citroen also designed them to have a cooling fan running 100% of the time. Certainly electric cooling fans have many advantages over engine driven types, but these are generally best exploited when they can supplement a flow of air through a radiator, not provide 100% of the flow...
To me at least, the fact that the electric fan is actually cutting out at all, suggests that things are not so bad as you think, as, if the system was struggling, even on the open road the fan would operate constantly, yes? And 80-85C isn't what I would consider hot either. By way of comparison, our (non-Citroen) late model cars thermostat doesn't begin to open until around 90C, and isn't fully open until 105C... For sure, you would expect Moby Dick's fan to run constantly when in traffic on a hot day, but if it can hold a reasonable temp when doing this I reckon it's OK. What do you think?
Brett
Thanks for the input. Yes, to a point I agree with you, I don't think I've got a huge problem any more, and after all of the work I've done I should bloody well hope not!
However my main concern is with the apparent fact that driving on the highway on an averagely warm day (OK, Yesterday was close to 30C, but the point remains) the fan is still being cycled in and out. This says to me that the airflow reaching the radiator at speed is still fairly minimal. I've driven (conventional) cars before that would boil their heads off in traffic, but run at normal temperature on the highway, due primarily to the 100Kmh wind doing the job that the fan wouldn't or couldn't do. It may be as you said that even at 100Kmh the airflow is close to zero in which case, yes, the fan is doing its thing satisfactorarily. It still seems odd, however.
My only concern is that if I encounter hot weather on the Peugeot Re-Run in April/May then things could get sticky. I will be carrying the engine driven fan and may bolt it back on if things get bad.
I may have hit on a partial solution by creating a temporary lip spoiler out of a sheet of flexible rubber and some gaffer tape. (see photo). A run in normal traffic this morning seems to indicate that this is supplying some kind of airflow. The temperature would lower to normal as soon as I was flowing with the traffic. Yet to be tested at 100Kmh, however.
It's possible also that the addition of the under tray (other photo) that I made yesterday will improve the airflow characteristic. There seems to me to be a larger cross sectional area for the hot air to exit past each side of the motor than there is cross sectional area of the intake duct, so perhaps the under tray assists in directing the air along the desired path.
Only time will tell!
Pottsy.
Thanks for the input. Yes, to a point I agree with you, I don't think I've got a huge problem any more, and after all of the work I've done I should bloody well hope not!
However my main concern is with the apparent fact that driving on the highway on an averagely warm day (OK, Yesterday was close to 30C, but the point remains) the fan is still being cycled in and out. This says to me that the airflow reaching the radiator at speed is still fairly minimal. I've driven (conventional) cars before that would boil their heads off in traffic, but run at normal temperature on the highway, due primarily to the 100Kmh wind doing the job that the fan wouldn't or couldn't do. It may be as you said that even at 100Kmh the airflow is close to zero in which case, yes, the fan is doing its thing satisfactorarily. It still seems odd, however.
My only concern is that if I encounter hot weather on the Peugeot Re-Run in April/May then things could get sticky. I will be carrying the engine driven fan and may bolt it back on if things get bad.
I may have hit on a partial solution by creating a temporary lip spoiler out of a sheet of flexible rubber and some gaffer tape. (see photo). A run in normal traffic this morning seems to indicate that this is supplying some kind of airflow. The temperature would lower to normal as soon as I was flowing with the traffic. Yet to be tested at 100Kmh, however.
It's possible also that the addition of the under tray (other photo) that I made yesterday will improve the airflow characteristic. There seems to me to be a larger cross sectional area for the hot air to exit past each side of the motor than there is cross sectional area of the intake duct, so perhaps the under tray assists in directing the air along the desired path.
Only time will tell!
Pottsy.
Attachments
Theory and dribble almost on the topic.
Was involved in BEARS raceing during the 80's and had the opertunity to watch John Britten and Mike Brozman building various 1000cc Brittens. The oil cooler was located in front of the bike in a high pressure zone with a tube running to near the rear engine mount in a negative pressure zone. Despite the tiny size of the cooler (about 5" X 2" from memory) this cooler was super efficient.
The point being that our wonderfull D's dont have a good pasage of air once it has been through the radiator. We're trying to force air where it don't wont to go.
With a laid down radiator over the air entry point we would have the possibility of then drawing the air flow down and back past the gearbox instead of into what looks like a high pressure engine bay. At motorway cruising speeds it should then be effiecient enough to be a passive system with the electric fans only coming on in traffic (maybe).
Chris.
Was involved in BEARS raceing during the 80's and had the opertunity to watch John Britten and Mike Brozman building various 1000cc Brittens. The oil cooler was located in front of the bike in a high pressure zone with a tube running to near the rear engine mount in a negative pressure zone. Despite the tiny size of the cooler (about 5" X 2" from memory) this cooler was super efficient.
The point being that our wonderfull D's dont have a good pasage of air once it has been through the radiator. We're trying to force air where it don't wont to go.
With a laid down radiator over the air entry point we would have the possibility of then drawing the air flow down and back past the gearbox instead of into what looks like a high pressure engine bay. At motorway cruising speeds it should then be effiecient enough to be a passive system with the electric fans only coming on in traffic (maybe).
Chris.
Well I've just been for a pleasant evening's drive to the top of Mt Dandenong, dined in Olinda then returned to the Northern suburbs. Carried 4 people in superb comfort. With the windows open the complaints (About the heat) from the ladies in the back seat were somewhat muted. (then I drowned 'em out with loud jazz from the Doof Doof!) Going up to Olinda the ambient temp was high 20's, coming home low 20's.
The down side is that the electric fan was on most of the way, and the temp had peaked at just under 200F by the time we stopped for a scenic view and car cooling stop at Fiveways.
Coming home she sat on the thermostat setting (180F roughly) with no problems but ran the fan again as soon as I hit the first hill. I guess this makes sense in that the engine is producing a motza of heat under acceleration and it has to go somewhere.
OK, I realise the geographical references will be lost on non-Melbournians, but the bottom line is that the bloody thing is NOT getting sufficient airflow from the combination of 12 inch electric fan and movement through the air. (Even with my tasteful orange chin deflector!)
Tomorrow I may experiment with a smaller mechanical fan, perhaps a Mini plastic jobbie (I happen to have a couple of spares!) in addition to the electric thing. Could be fun if the Great White Whale sounds like a Mini under the bonnet!
I guess if all else fails it's back to the drawing board and the Cessna propellor, but I hate to admit defeat so easily!
Attached are photos of the fan installation and the thermo switch. No smart comments about the overflow bottle either, it's only temporary.
(Oh, and who noticed a couple of the other toys in the background to the photo of the undertray? 504 Ti belongem No1 son, and Mini, belongem me!)
Cheers, Pottsy.
The down side is that the electric fan was on most of the way, and the temp had peaked at just under 200F by the time we stopped for a scenic view and car cooling stop at Fiveways.
Coming home she sat on the thermostat setting (180F roughly) with no problems but ran the fan again as soon as I hit the first hill. I guess this makes sense in that the engine is producing a motza of heat under acceleration and it has to go somewhere.
OK, I realise the geographical references will be lost on non-Melbournians, but the bottom line is that the bloody thing is NOT getting sufficient airflow from the combination of 12 inch electric fan and movement through the air. (Even with my tasteful orange chin deflector!)
Tomorrow I may experiment with a smaller mechanical fan, perhaps a Mini plastic jobbie (I happen to have a couple of spares!) in addition to the electric thing. Could be fun if the Great White Whale sounds like a Mini under the bonnet!
I guess if all else fails it's back to the drawing board and the Cessna propellor, but I hate to admit defeat so easily!
Attached are photos of the fan installation and the thermo switch. No smart comments about the overflow bottle either, it's only temporary.
(Oh, and who noticed a couple of the other toys in the background to the photo of the undertray? 504 Ti belongem No1 son, and Mini, belongem me!)
Cheers, Pottsy.
Attachments
I have a theory!!!! Electric fans came into common use on cars that commonly run thinner and often smaller radiators than a DS has. Electric fans also always seem to have shallow blades (as opposed to the DS wide blader mechanical) and I seem to find they can make alot of noise but not "feel" like they move great volumes of air at times (my VW has 2 very large electric fans standard with a high and low speed which it decides on itself). If you are ONLY using an electric I would always expect a DS to want that fan on ALWAYS.They really do produce some flames in them combustion chambers! The only time I've seen an electric fan help cool a DS is when it is supplementing the mechanical fan cooling. The electric fans I have seen fitted to DS have always been noisier than the mechanical fan ever seems to be.
Remember that your electric fan only has one constant speed. The DS original mechanical has a range of speeds dependent on engine revs. How much volume of air IS moving through that engine bay really?
We seem to have decided that all the air sucked up the radiator shute is SUCKED and not forced, yeah?
Does it make any sense? I'm tired and need to go sleepies.............
Remember that your electric fan only has one constant speed. The DS original mechanical has a range of speeds dependent on engine revs. How much volume of air IS moving through that engine bay really?
We seem to have decided that all the air sucked up the radiator shute is SUCKED and not forced, yeah?
Does it make any sense? I'm tired and need to go sleepies.............
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I'm loving this thread and can't wait for the next installment...
Along the same lines of what a modern electric fan can or can't do... There was a comment earlier in the thread about moving throm a 2 core to a 3 core radiator. Whilst another core adds more surface area, might it not also restrict the flow of air? Might the Cessna be better able to cope where the modern fan struggles. (This rubs me the wrong way as I believe that in the intervening years we should be getting better at this stuff, not worse.)
Also my thoughts turn to how hot air escapes the engine bay. Can this be improved? No amount of sucking will help of there is just a pressure build-up in the bay - which might explain moby's problem at 100km/hr.
Along the same lines of what a modern electric fan can or can't do... There was a comment earlier in the thread about moving throm a 2 core to a 3 core radiator. Whilst another core adds more surface area, might it not also restrict the flow of air? Might the Cessna be better able to cope where the modern fan struggles. (This rubs me the wrong way as I believe that in the intervening years we should be getting better at this stuff, not worse.)
Also my thoughts turn to how hot air escapes the engine bay. Can this be improved? No amount of sucking will help of there is just a pressure build-up in the bay - which might explain moby's problem at 100km/hr.
I think that by slow and gradual wearing away of the alternatives I'm arriving at one inescapable conclusion. That Mr Citroen put that huge noisy bloody thing in for a good reason, and that was so the air would get moved sufficiently to keep the whale cool.
My thought late last night of fitting a smaller mechanical fan was flawed somewhat. In my tired state I contemplated using a Mini fan since they're thin and plastic and would sort of fit between the electric and the hub. Unfortunately I ignored the fact that a Mini fan blows the air through it's core (but rotates clockwise looking at the motor) and consequently the vanes are the wrong way around. Man, THAT would have confused the issue!
The only other fan blades I've got were too thick.
Anyway, I've re-instated the Cessna propeller for now, much as it goes against the grain.
The thickness of the core may be an issue I guess. I'd love to be able to do airflow analyses on the Cessna jobbie and then the electric. Unfortunately I have neither the test equipment or the patience to do so.
I've seen the 12 inch electric fan variously quoted at flow rates of between 900 and 1300 Cubic Feet per Minute (CFM) I'd love to know if anyone can quote a flow figure for the original propellor.
Oh, and has anyone had experience with the after market (Davies-Craig as well I think) viscous couplings that one can buy? This may be another alternative to explore yet.
OK, that's it for now.
Stay tuned for the next exciting instalment!
Will Masher the baby strangler reach the beleaguered garrison in time to save the toast from burning?
Will the phone stop ringing before he gets there?
Do we care?
These are all questions!
Pottsy.
My thought late last night of fitting a smaller mechanical fan was flawed somewhat. In my tired state I contemplated using a Mini fan since they're thin and plastic and would sort of fit between the electric and the hub. Unfortunately I ignored the fact that a Mini fan blows the air through it's core (but rotates clockwise looking at the motor) and consequently the vanes are the wrong way around. Man, THAT would have confused the issue!
The only other fan blades I've got were too thick.
Anyway, I've re-instated the Cessna propeller for now, much as it goes against the grain.
The thickness of the core may be an issue I guess. I'd love to be able to do airflow analyses on the Cessna jobbie and then the electric. Unfortunately I have neither the test equipment or the patience to do so.
I've seen the 12 inch electric fan variously quoted at flow rates of between 900 and 1300 Cubic Feet per Minute (CFM) I'd love to know if anyone can quote a flow figure for the original propellor.
Oh, and has anyone had experience with the after market (Davies-Craig as well I think) viscous couplings that one can buy? This may be another alternative to explore yet.
OK, that's it for now.
Stay tuned for the next exciting instalment!
Will Masher the baby strangler reach the beleaguered garrison in time to save the toast from burning?
Will the phone stop ringing before he gets there?
Do we care?
These are all questions!
Pottsy.
Moby DS
Like Pajamas, I find the tribulations without a successful triumph to be intriguing. Pajamas has a point in that systems analysis suggests that air output should be greater than input.
Logic would suggest that that a solution is available but little progress is being made.
Does the chequerplate sump guard restict the egress of air? Could it be "lipped" on its trailing edge to create a low pressure area to suck air from the engine bay?
Does running the heater and internal fan improve the situation?
If so could an auxillary radiator/s (maybe an A/C core) be located where it can get airflow?
As a matter of absolute last resort, this suggestion will hurt, Pottsy. Would ventilation of the bonnet by louvres (or axe-cuts of frustration!) assist. You might want to play around with a damaged/2nd hand example to create an efficient prototype.
Like Pajamas, I find the tribulations without a successful triumph to be intriguing. Pajamas has a point in that systems analysis suggests that air output should be greater than input.
Logic would suggest that that a solution is available but little progress is being made.
Does the chequerplate sump guard restict the egress of air? Could it be "lipped" on its trailing edge to create a low pressure area to suck air from the engine bay?
Does running the heater and internal fan improve the situation?
If so could an auxillary radiator/s (maybe an A/C core) be located where it can get airflow?
As a matter of absolute last resort, this suggestion will hurt, Pottsy. Would ventilation of the bonnet by louvres (or axe-cuts of frustration!) assist. You might want to play around with a damaged/2nd hand example to create an efficient prototype.
Hey, Pottsy, you're famous. Check under the spotted in Vic thread...
http://www.aussiefrogs.com/forum/showthread.php?p=298995&posted=1#post298995
http://www.aussiefrogs.com/forum/showthread.php?p=298995&posted=1#post298995
This is a link to info on an air pressure switch (both pressure and vacume) and can be used to build a surface air pressure guage. This would allow you to test the front surface of the D for the best location of the intake or to guage the success or otherwise of adjustments made to the intake. You could also search the rear of the engine bay and underside of the driver passenger floor pan for areas of negative pressure with a view towards developing a more effiecent flow of air through the rediator and engine bay.
http://autospeed.drive.com.au/cms/A_1490/article.html
Chris.
http://autospeed.drive.com.au/cms/A_1490/article.html
Chris.
On the air escaping side............my very first car, a DS23 IE auto had the lip on the bottom of the windscreen trimmed away to allow air to escape there (mind you that car never really overheated on me). There are numerous D's around with venting holes cut into the sides of the front guards. If you place your hand there while the engine is running there is always heaps of nice tropical air flowing out of the holes!
Getting rid of all the hot air from under the bonnet is also what I've concluded is the 'problem'.
As Darren suggested, trimming the rubber seal at the base of the screen would have to be helpful.
Along the same lines, how about inserting a spacer of about 5mm under each bonnet hinge? This would have the effect of raising the trailing edge of the bonnet. IMO, 5mm is about as much gap as you could introduce without looking like your bonnet was out of alignment.
Interestingly, this would seem to be the fix employed on a DS featured recently in an article from Uganda. Whilst this mod wasn't mentioned, a gap of about 2 inches was very evident in the pic shown.
As Darren suggested, trimming the rubber seal at the base of the screen would have to be helpful.
Along the same lines, how about inserting a spacer of about 5mm under each bonnet hinge? This would have the effect of raising the trailing edge of the bonnet. IMO, 5mm is about as much gap as you could introduce without looking like your bonnet was out of alignment.
Interestingly, this would seem to be the fix employed on a DS featured recently in an article from Uganda. Whilst this mod wasn't mentioned, a gap of about 2 inches was very evident in the pic shown.
Chris Dunham said:
Fascinating thread this! From what I understand, the size of openings to admit air isn't very important, rather it is the size of the space into which the air is moving and also the pressure differential that allows ready outflow of air.
Consider some of the aerodynamic vents that Costin put on streamlined body shells in the 50s-60s.
All of the rear engined Renaults (of which I've had a few over the last 35 years) cool well but only if the shrouding around the engine is fully in place. If, for example, the undertray is removed, hot weather causes trouble, but if they are in place the air all moves through the radiator and out the back of the car in a low pressure area.
I suspect that the issue is exactly what some of these latter posts say, that is a need to let more air out from the area behind the radiator, so that the air pressure in that area is lower. Some elegantly styled grills in the right place might be the go, or some experimenting with the length of that undertray, or both.
Assuming the water pump is at the hot end, the sensor should be about right (the Renault 16TS has the best I can think of, bolted to the head by the exhaust manifold, so measuring cylinder head temperature).
I'm no DS expert, but it does sound as if the original fan was OK! By contrast, with much care about airflow, the Renault 16 fan rarely comes on except when stationery.
I like the idea of discretely enlarging the slot behind the bonnet.
Best of luck (oh, and I can't make Philip Island this year but 2007 is pencilled in)
Cheers
Episode 95, Back to Standard! (A bit like Star Wars this!)
OK, today I restored the Cessna jobbie back to its rightful place and banished the upstart electric thingie to the shelf in the garage.
A drive over to French Connection in 35+ degree heat saw the temp gauge sit stubbornly on 180F and not move for anything! Damn, I hate it when the manufacturer knows better than me!
I like the idea of a bit of a spoiler lip on the checker plate, however, and I may look into that, although at the moment the undertray is nice and smooth.
I've also contemplated some shark gill type vents in the mudguards, but really don't want to attack the beast with cutting wheels yet. (Or an axe! I'm not that frustrated yet!) Same goes for lifting the rear of the bonnet, a bit too "Torana A9X" for me! It may still happen, however, as there is certainly a lot of heat to shift.
In the meantime, I'm conceding defeat, happy that the Whale will run cool in the hottest of climates, as long as I leave the cooling system alone! (Somewhere there's a Citroen designer laughing hysterically along the lines of "Stupid Australiens, do they not realise we are French and know best?")
Next on the list is addressing myself to the hydraulics, not modifying, I hasten to add, just tidying up and trying to find the cause of the frequent cycling. First stop is the brake valve which I shall attempt to replace tomorrow. Wish me luck!
Oh, and John. Sorry to hear you won't be at the Shannon's. I'll try to take a few happy snaps and maybe post them for you. This year's featured Marque is Porsche. Anyone who saw Top Gear on Monday will get a bit of a giggle I reckon!
Cheers, Pottsy.
And as the sun glides across the horizon, and the ship sinks slowly in the West we bid farewell to Balham, Gateway to the South!
OK, today I restored the Cessna jobbie back to its rightful place and banished the upstart electric thingie to the shelf in the garage.
A drive over to French Connection in 35+ degree heat saw the temp gauge sit stubbornly on 180F and not move for anything! Damn, I hate it when the manufacturer knows better than me!
I like the idea of a bit of a spoiler lip on the checker plate, however, and I may look into that, although at the moment the undertray is nice and smooth.
I've also contemplated some shark gill type vents in the mudguards, but really don't want to attack the beast with cutting wheels yet. (Or an axe! I'm not that frustrated yet!) Same goes for lifting the rear of the bonnet, a bit too "Torana A9X" for me! It may still happen, however, as there is certainly a lot of heat to shift.
In the meantime, I'm conceding defeat, happy that the Whale will run cool in the hottest of climates, as long as I leave the cooling system alone! (Somewhere there's a Citroen designer laughing hysterically along the lines of "Stupid Australiens, do they not realise we are French and know best?")
Next on the list is addressing myself to the hydraulics, not modifying, I hasten to add, just tidying up and trying to find the cause of the frequent cycling. First stop is the brake valve which I shall attempt to replace tomorrow. Wish me luck!
Oh, and John. Sorry to hear you won't be at the Shannon's. I'll try to take a few happy snaps and maybe post them for you. This year's featured Marque is Porsche. Anyone who saw Top Gear on Monday will get a bit of a giggle I reckon!
Cheers, Pottsy.
And as the sun glides across the horizon, and the ship sinks slowly in the West we bid farewell to Balham, Gateway to the South!
pottsy said:
Well then, Balham indeed. Toothbrush holemanship comes to mind!
The photos would be great - I've too much on, basically. Nearly made it to the DS 50th in Paris though (missed by 2 days!!).
Now, please don't raise the bonnet: it's unthinkable! Discrete slots, possibly without any grill to draw attention to them, or something clever at the back maybe, but the Torana look just isn't on.
I wish I knew more about under-car air pressures, as that undertray just suggests discrete and effective air movement to me.
I'll be really interested to hear more.
cheers