Hey guys,

So before I get to my question, awhile back I had posted about my pannier flying off and options for replacement. So I bought a complete replacement on ebay and modded the hinge system. I did this on the other one as well. Here it is!

Bottom:


Inside, kind of dirty, I know:


On the Bike, can't even tell:



I'm not losin' another one of those things.



So now for my question(s): I also previously posted about it running hot. I've gotten it to the point where it runs consistently at a reasonable temperature, but it's still slightly warm. Based on this, I assume that everything is working as it should because the temperature of the bike noticeably changes with the temperature of the day. On a cool day, it runs cool. On a warm day, it runs warmer.

I was reading around on the forum and found a thread that mentioned the difference between the older and 'newer' radiators and water pumps. Apparently, the older radiators had a larger capacity and the older water pumps actually pumped more water at a faster rate. I saw a couple forums that mentioned replacing the 'newer' radiators and pumps with the older ones. I would like to look in to this.

-Is there anything I need to know, or is it just a simple swap of parts? I want to make sure that the older water/oil pump will fit right on the 16v engine.
-What year radiator should I look for? And what year pump, just pre-16valve?
-I was reading up on some of the older pumps and learned about an issue with the impeller nut coming off. Should I avoid buying that sort of pump?
-I also see a pretty big difference between the original cast impeller and the 'bladed(?)' one. Any difference in pumping power/force there?

Thanks in advance.

The 3 row radiator core is from an 83 or 84 model. Occasionally you see them come up on fleabay and are easilly identified because of the extra row of tubes. If you look at the later radiators you can see where they would go. When you fit one to a 16v engine you will have clearance problems with the fan mountings but removing the leg of the mount will do the job, I did it to my K1100 and I know of others that have done the same and all without problem. The cast impeller will move more coolant than the pressed steel but that may not be at all neccessary as you can move the coolant too fast and it doesnt get a chance to cool, not at all common but it does happen and not just to Ks. If you want to use the cast impeller you need to get the latest in seals and spacers etc that is meant fot the pressed steel impeller and then take 3mm from the boss of the cast impeller and it will fit.

ive got a 3 row radiator ....as of now ...just need to do some bending of fins etc to get it looking good

might take a month or two before its fitted up though

im guessing thatr the added cooling ability will let the water circulate a bit more ....maybe not much ...but some ...after all its kinda dependant on the thermostat temperature and all the rest

i have noticed that when a hot day is happening ...the radiator tends to blast hot air back at your legs for longer than on a cooler day with the later 2 core (85 on radiator ) ,,,,unless you put an override switch on the fan...allowing it a bit more duty (like in city traffic) than when it is in the normal failsafe running mode .

Awesome info.

@rickg:
So they started using the smaller radiators on the 1985's? I see a couple on ebay that say they're for a '1984-1989', so that makes me think they changed them in mid-'84.

Regarding the pump, did the older pumps actually hold more water? This would mean the casing itself would be slightly different towards the front if that's the case. And if that is indeed the case, would that casing fit the 16v bike?

I'll keep that in mind about the impeller. Maybe I'll do the radiator first and see how that effects things. I'm planning on throwing an aftermarket fan on it either way. My fan is squeaky due to a drying / dried bearing.

@charlie99
I don't really mind the hot air on my legs for some reason. I'm hoping that by swapping a 3 row radiator in, it will bring my temp down to where it belongs, especially since it's already running a little warmer than it should on nice days. I don't wanna see what it does on a 104 deg F day in summer.

Many people don't know about the difference in radiators, the 2 row are the same right through to the end of the K1100 as for the pumps as far as I know the housings are the same, I have never seen one that is different. There was an update about 91 when the coolant impeller and seals were changed and I think at the same time the oil pump gears were also changed. The pumps are interchangeable right through to the end of the K1100 and the 1200 may be the same but I have never delved into them.

The updated pump does fit the K1200 too. It's listed as a replacement for the whole of the K-Series 'Brick' range.

Part #11 41 1 461 173

Rabidchiwawa007 wrote:Regarding the pump, did the older pumps actually hold more water? This would mean the casing itself would be slightly different towards the front if that's the case.

The pumps up to the change in -91 did spin faster due to a different gearing, which is the main reason to the reduction in the pump capacity.

If I wear to swap pumps (or just gears), wouldn't that in turn effect oil pressure as well, making it lower?

You must change the complete pump due to a different housing,
the older pumps should also have a better capacity at the oil side.

You can't swap just the gears the housing is in fact different to suit
the different gear sizes of the oil pump although the coolant pump is
essentially the same. Sorry for the wrong info there.

So if I'm looking for an older pump, I could look for anything pre-1990 and that would have the different gearing?

Correct.

Rabidchiwawa007 wrote:So if I'm looking for an older pump, I could look for anything pre-1990 and that would have the different gearing?

I would be inclined to go for the earlier pump I don't see any advantage in the later one. I would consider that having a higher volume oil pump for an engine where the tolearances are getting larger would have its advantages.

I have a 3 row radiator and a water pump with the updated shaft & impeller that I took off a 1985 k100rt parts bike.
I have no known history from the PO on when these parts may have been updated/installed, but the bike had 235,000 miles on the odo.
I can say that the water pump/oil pump were not leaking when I took them off. If I were going to use this pump I would definitely re=seal it anyway. It has been sitting with no water in it in my garage for a few months.
I also have the BMW pressing plug tool that is absolutely needed to install a late type water pump ceramic seal without ruining it.
All of these items are available for a reasonable offer.

That is the later model pump from 01/90, with reduced capacity.

I'm wondering if you are actually having a temp problem or maybe it's only your perception of a problem.?
Normally, you can start up and let it idle for maybe 15-20 minutes at slightly higher than idle. When the coolant reaches the proper operating temps, the fan will switch on....maybe 195 degrees (only approx.).
After a couple of minutes the temp will drop only a few degrees & the fan will cycle off again.
If all of that occurs, your temps are probably correct. As for on road conditions, the coolant will not get warm enough to start the fan very often (at speed).
As designed, The thermostat will throttle the water flow to insure the engine stays hot enough, the fan will add airflow as required to keep it cool enough.
Only, if you are staying hotter than that level.......so the fan stays on all the time, would you really have any issue.
The (very) hot air off the radiator on your legs & fuel tank is completely normal......the hotter the weather.....the more toasted your legs get.
I find that often times owners attempt to get temperatures to run cooler than designed. The engine really needs to be fully up to designed temps to run correctly.
If You are fortunate to ever find a pair of these aftermarket heat shield (No longer made)........I think they help ALOT especially here in Phoenix.



PS: mine are not for sale....LOL

Rabidchiwawa007 wrote:Awesome info.

@rickg:
So they started using the smaller radiators on the 1985's? I see a couple on ebay that say they're for a '1984-1989', so that makes me think they changed them in mid-'84.

Regarding the pump, did the older pumps actually hold more water? This would mean the casing itself would be slightly different towards the front if that's the case. And if that is indeed the case, would that casing fit the 16v bike?

I'll keep that in mind about the impeller. Maybe I'll do the radiator first and see how that effects things. I'm planning on throwing an aftermarket fan on it either way. My fan is squeaky due to a drying / dried bearing.

@charlie99
I don't really mind the hot air on my legs for some reason. I'm hoping that by swapping a 3 row radiator in, it will bring my temp down to where it belongs, especially since it's already running a little warmer than it should on nice days. I don't wanna see what it does on a 104 deg F day in summer.

The fan will switch on at 103deg C which is about 216 deg F. My K1100 will on very hot days (over 100 deg F) will run a bit over the half way mark on the gauge but will stay there regardless of load and hills etc. Even towing a camper on hot days it will get to that mark and no futher if I am moving at anything over 15mph and if under the fan cycles on/of very effectivly with a 3 row radiator. Mind BMW don't measure the temp as it exits the engine they measure it at the pump which in my opinion is wrong.

So the question is: what actual temp conditions is Rabidchiwawa007 experiencing?
Oh......BTW>>>>who makes these nifty little smiley things???? I'd like to see one where the light bulb comes on ....on top of the lil smiley's head when he "Gets It"

Well, lets put it this way:

I have the fan on a manual switch. I turn it on when it gets to the half way mark on the temp gauge. As such, the fan is usually on, even on cold days. I'm hoping to achieve a better temperature control for when it gets hot during summer. Since its running a little warm now, I'm guessing that its going to be a bit worse during summer. If a bigger radiator and faster pump will do it, I'm all for it. I've found that older things tend to be better made, and more thought out; for quality rather than profit. If I can swap in a better and bigger radiator that's designed to run it cooler, that's what I'll shoot for. Also, I'm a bit inebriated right now, so I apologize for any bad grammar if there is any.

How hot does the temp get without using the manual switch (until the fan comes on by itself?
Keep in mind that no matter how much air you push through the radiator, the motor will not cool lower than the thermostat opening temp.
If you "force" the water colder the thermostat is designed to slow the flow of the water till the engine can heat it up again.
As I said before: does the fan turn on automatically and if so, at what temp on your dash gauge.

The switch shown below is mounted in the water pipe coming out of the engine at the left front behind the front of the fuel injector rail. I believe you have to remove the air intake box to work on the switch.
As rick said......the switch is designed to activate the fan at 216 degrees F.
Conversely, the thermostat does not fully open and allow complete coolant flow until 197.6 degrees F.
So, at idle.......the fan should come on by itself at 216 and shut back off as the water cools down to like maybe 200.
Natural conditions probably allow the water to come up above 216 before...... at some point the warning light on the dash will illuminate. If that never comes on, chances are you are running ok. If, by chance the fan should fail, I believe that the fuel injection controller will shut the engine off at some point. I am not sure about that point but others here certainly will be.
In general, putting a "fan override switch" in the circuit is a bad, bad idea.
I wonder if you know???? Did the installation of the override switch alter any of the original fan wiring to the switch in the picture?



That said, the engine is designed to run that warm or slightly warmer.
If you are trying to keep it much cooler than that, you are going in the wrong direction.

I had this issue with the fan not turning on due to the ground signal from the motronic unit not being sent. So I simply wired the fan to a switch directly off the battery. The fan used to turn on when the temp gauge read about half. The idiot light turned on a couple times, but since then I have done a few radiator flushes and it hasn't come in since. I turn the fan on when the temp gauge gets to around half.

Adding this switch altered nothing from the temperature sensor on the metal water boot.

The thermostat that's in there is set to open at 82 celcius, which is 3 celcius below stock, so it should run a little bit below the half mark while moving. The bike currently runs in an okay heat range, usually right at the half mark on a nice cold day. But when I'm stopped, with the fan running, it slowly climbs hotter and hotter, getting past half a bit; and this is on cold days. It's my hope to eliminate this in preparation for summer. I want the thing to be able to sit forever and not overheat.

Rabidchiwawa007 wrote: I want the thing to be able to sit forever and not overheat.

I suppose it depends on your definition of overheating.

To my mind, being in the upper range of the safe operating temperature range, with the fan running constantly, isn't overheating. Ride a K1 in town traffic and the fan will be running almost constantly, even in winter.

Overheating for me is when the temperature warning light begins to glow. Anything else is within the designed tolerance. The only thing to do is to check the coolant level and specific gravity regularly (and possibly change the engine oil and filter sooner than the service schedule advises).

If you let ig get hot like real hot does it cool quickly when you get moving or does it really take its time.
For an example If you are going up a mountain pass that is 2 miles long and it slowly gets hotter and hotter till you are looking at it thinking that the light will be coming on at any time now then you reach the top and go down the other side would it take the whole 2 mles to cool down again or would it be back to normal in about 1/2 mile or less.
I am thinking bad radiator here.
You say a 82 thermostat where did you get that because the only aftermarket trhrmostats I have found are too short and let coolant bypass the radiator like it does for quick warmup. When the thermo gets to operating temperature it should block that bypass passage. If yours doesn't block that passage you will have overheating problems similar to what you describe. I would put the original or a good OEM back in and try that.

It's the climbing of temperature while stopped that worries me. To me, it looks like it will keep climbing until the light comes on. It's still nice and cold here, and I don't want to see what happens when it hits 104 or so during summer.



It cools pretty quickly in that situation. Probably even sooner than a half mile. But that's the whole point of what in trying to do. I don't want it to heat up like that in the first place. I forget which thermostat it is, I found a thread somewhere on the forum that suggested one that was 82C. That's the one I got. It's the same size, fits right and everything.

the toyota corolla (from about 89 through ) is an almost exact replacement ....with the bypass shutoff extra bit at the back ...have a look at the tridon models ....ill get the number next time im over at super cheap ...comes in a range of temperatures as well ...although mostly stocked is the 82 deg c version from my looking in the shops .

i think ned made this discovery before i joined some years ago

Ah, that's the one. It is an 82C thermostat for an older corolla ('89 ish)

K-Shields are still available from the guy who makes them. Somewhere around my office I have his contact info. They are more expensive than you might think, which is why I haven't jumped on them myself.

You can very much reduce the heat on your legs by paying very careful attention to the placement and condition of the big U-shaped gasket that fits between the underside of the gas tank, the top of the air box and the inner side panels. Pay special attention to the two little triangular tabs that are designed to fit into the gap where the inner side panel, gas tank and air box intersect. If that gap is not carefully plugged by correctly positioning that gasket, something way too many techs do not do, then you get a jet of scalding hot air on your inner thigh that in Southern California summers will raise up big fat red welts on your inner thigh. If you are a younger man still chasing the ladies, they emphatically do not want to see red welts on your legs when a chance of intimacy arises, lol (plus they itch like crazy when they heal and it's not someplace you want to scratch in public). But seriously, the correct position of that gasket is the key to cool legs on a K bike.

Rabidchiwawa007 wrote:It's the climbing of temperature while stopped that worries me...It cools pretty quickly in that situation...

Hi there, have you checked the refrigerant level at the recover depot, during the temperature raise? Is there fluid transfer to the depot before or while the fan works?
You should be able to stay at idle with the fan starting and stoping, without ever passing fluid to the recover depot.
If this is not the case you may have problems with the radiator cap, in my case it was the gaskets.
Hope this helps
Best regards
JAP

There is no fluid transfer. That level stays the same at all times. The radiator cap checks out okay.

#1 I think you need to re-install a correct stock thermostat.
the engine needs to be able to obtain it's correct temp, quickly even in cold temperatures.
#2 You need to find the fault in the automatic fan control circuit and fix in RIGHT.
Your problem was not with the thermostat, it was with the fan control circuit. to the (Temperature sensing switch unit) a lightly colored Relay in the relay Box. See the photo below.
You need to correct THAT!

You may also have a poor or intermittent connection at one of the brown grounding wire eyelets where they hook to the frame spine under the tank.
I expect that the failure of the Temperature sensing switch unit to start the fan at the appropriate moment, may also be due to an open connection either between the temp sensor and the switch relay unit or between switch relay and the fan.
I seriously doubt if the Temperature sensing switch relay is faulty, but it's possible.
It looks like this:


YOU NEED TO FIX THIS.
If you elect to start running some electrical tests, you should have good continuity between pin #A2 at the temp switch control relay harness end and the positive power connector at the fan motor.
You should have little or no ohms resistance testing between the negative connector at the fan unit and the battery ground post, Do this with both the fan connector at the motor and the temp sw. connector at the relay disconnected.
Pin #A3 at the temp switch relay operates the warning lamp, so we can disregard that for now.
Pin #31 at the same relay should be 0 ohms or nearly that to the battery ground stud and to the negative side connector at the fan motor. (all the grounds are common) (light brown).
Pin # 15 goes to the anti theft device and to the horn relay. I think we can disregard that.
Pin #9 gets positive power from Fuse #6. you can check continuity between those 2.
Pin #E goes to one of the 2 wires on the temperature sensor on the Radiator hose Tee on the top of the engine left side behind the radiator.
The other pin on the temperature sensor goes to the Fuel injection computer so that it can richen the fuel mixture when it's cold. It does not normally directly effect the fan switching circuit.
Your dash temp gauge appears to be working, it is controlled by a separate sensor mounted in the water pump coolant drain plug hole.

Currently, you are running an "end around" jury rigged solution to an electrical fault.
This 'Fix" will fail you someday at a most difficult moment far from home. Example: your aftermarket switch fails to turn on the fan due to an internal fault, water, corrosion, whatever OR some of your "custom installed wiring" reveals a workmanship defect that causes an "open or short".

Man up & fix this right.
(I see no harm in leaving the override switch in the circuit after you have the automatic fan control operational if only for "paranoia?) I would remove it once the fault is corrected.
If you want the temperature sensing switch control relay from the picture, I can send it to you for $20 delivered to your door in (San Diego)......can't really remember.
I do not know if it actually works, but the bike it came from was a running bike when I bought it. I'm not going to tear into my bike to test it.
I hope you get into fixing this fault with a positive attitude.
You will be very happy if you can correct it with your own diagnosis.
Hugs, ibj

I have found that the temp on the K1100 rises very quickly on a hot day but once the fan cuts in it also cools quickly. This most recent summer was the first realy hot summer with the K1100 and I was a bit supprised at first just how fast the temp came up when going slow or stopped but it is OK. The fan starte working about the width of the needle below the red section.
The K100 was much the same although I didn't have an OEM gauge but an aftermarket that was connected directly into the water stub where the fan and computer gets the signals.
From my own point of view the temp rising that much is not at all ideal but it does seem to be OK. I was thinking that maybe a better thing would be to have the fan come on at a slower speed when your speed drops below a nominated speed like 10mph/16kph so that it would prevent the heating up in the first place and a better fan is also a much needed item. One that is a bit quieter and doesn't sound like an F111 warming up.

just an update re the thermostat

this is what i found on the shelf at one of our local parts shops

tridon tt214-180 seems to be the one that is on the shelf most often

TT214-140	Thermostat	Thermostat	Opening Temp: 60°C Flange Dia: 48mm Foot Dia: 27.7mm Height: 35mm Bypass style thermostat with jiggle pin.
TT214-160	Thermostat	Thermostat	Opening Temp: 71°C Flange Dia: 48mm Foot Dia: 27.7mm Height: 35mm Bypass style thermostat with jiggle pin.
TT214-170	Thermostat	Thermostat	Opening Temp: 77°C Flange Dia: 48mm Foot Dia: 27.7mm Height: 35mm Bypass style thermostat with jiggle pin.
TT214-180	Thermostat	Thermostat	Opening Temp: 82°C Flange Dia: 48mm Foot Dia: 27.7mm Height: 35mm Bypass style thermostat with jiggle pin.
TT214-192	Thermostat	Thermostat	Opening Temp: 89°C Flange Dia: 48mm Foot Dia: 27.7mm Height: 35mm Bypass style thermostat with jiggle pin.

just for those that might want to know
..there maybe crossreferences to other brands ...in other countries ...not sure but claimed to suit totota corolla 89- on
btw you will need to find the rubber sleave type seal that fits around the front sealing face of the thermostat

hope it helps someone

Thanks Charlie. I went into the only store here and asked about getting one and left it with them so they could look at a less busy time and they said no go the dirty rats, they usually are very good with that type of thing. Ah well I will forgive them.

19.95 at super cheep rick

i have an alternate source as well, ill ask him for a price ....probably tommorow

Its not that I really need one but was going to put a new one in when I put it back on the road.

Is Super cheap conversely proportional to Super dependable?????
I wish I had a nickel for every time a Harbor Freight socket or wrench failed & busted my knuckles at a time when a particular difficult mechanical situation arose and the tool would be stressed.
I can just see the steam rolling out of this BMW's cooling system, on some summer's day, when 1/2 way across the Death Valley desert with a broken thermostat......maybe we'll have a nifty HF tools on hand to attempt a repair?

When Super cheap first starte about 30 years ago they were not cheap and were very cheap on quality but over the years they have become better on quality by selling good brands but the name still does not reflect the cost of the parts and tools.

my other supplier has them for 18.00
he also said he would probably have the seal

They don't get anymore clear cut than that. To put it in laymans terms it's shagged.

is this "found" or "happend" durring remooval ....
in any case ...giggles... it aint gona work right i guess ..

This is just a representative photo of the type of damage I have found over the years with automotive thermostats.

IMO an inexpensive thermostat is more susceptible to this kind of failure because of cheap manufacturing/design.
again IMO, it is best to buy a brand name thermostat from an oem manufacturer or at least from a highly regarded aftermarket brand like "Stant".
A thermostat requires that the pin in the top center area have a solid surface against which to apply the pressure created by the "wax" pellet as it warms. Having the center pin securely anchored at the top allows the pressure created in the copper wax pellet to force the water valve open downward against the tension spring hence allowing the coolant to pass through the system.
If the upper bridge of the thermostat fails as shown in the photo, the thermostat is stuck permanently in the closed position causing overheat within 10 minutes of starting up from cold.
In other scenarios, if the lower structure should break the spring pressure is released and the water valve generally cocks sideways as the spring is partially un caged leaving the valve permanently partially open.
In that event the thermostat often cannot open fully, resulting in overheat during hot weather or resulting in the failure of the engine to warm up to spec temps in cold environment.
Economizing on a cheap thermostat can be a very expensive proposition.
I believe a new one for my K100 is $54 at Max BMW + shipping and handling.
Depending on how you look at it, it might be a bargain.

Bottom line here is that I can ramble on till I'm blue in the face and there is some segment of the users who will still try to:
#1 Try to un-naturally "force" the engine to run cooler than it is designed to #2 Try to make the fan run when it shouldn't by hacking the wiring systems #3 Create a false savings image by buying the least expensive parts available
This is what makes a new BMW into an old BMW

re the update the 18 dollar version is the same product just at a near wholesale (trade ) price from a mate i have been buying off for 20 years or so.

[quote="ibjman"]Is Super cheap conversely proportional to Super dependable?????
I wish I had a nickel for every time a Harbor Freight socket or wrench failed & busted my knuckles at a time when a particular difficult mechanical situation arose and the tool would be stressed.
I can just see the steam rolling out of this BMW's cooling system, on some summer's day, when 1/2 way across the Death Valley desert with a broken thermostat......maybe we'll have a nifty HF tools on hand to attempt a repair?[/quote]



It is oft said that the cheapest thing on a BMW is the rider.