how to tell a good water pump from bad ?

[pablo0874]

evenin alll,well ive just took the water pump off and replaced it with a new from milner, easy job 1 hour tops following the download on here ,
what i cant figure out is the one i took off is exactly the same as the new one its cured the leak now and the overheating ,but how can i tell if the one i took off was any good ,because the overheating could have been caused by a leaking gasket and air gettiing in if this was the case what would a broken water pump look or behave like as its the same as new:nenau:nenau:nenau:nenau

 

[Fez_uk]

how much was the new water pump?

 

[rustic]

evenin alll,well ive just took the water pump off and replaced it with a new from milner, easy job 1 hour tops following the download on here ,
what i cant figure out is the one i took off is exactly the same as the new one its cured the leak now and the overheating ,but how can i tell if the one i took off was any good ,because the overheating could have been caused by a leaking gasket and air gettiing in if this was the case what would a broken water pump look or behave like as its the same as new:nenau:nenau:nenau:nenau

Don't forget the water pump also houses the viscous fan mechanism, that allows drive to the fan as the temperature increases.

If this is faulty, and doesn't run the fan, it will overheat.
Q.E.D.
I rest my case.

 

[pablo0874]

how much was the new water pump?

47£ plyus vat 7 quid delivery =65

 

[pablo0874]

Don't forget the water pump also houses the viscous fan mechanism, that allows drive to the fan as the temperature increases.

If this is faulty, and doesn't run the fan, it will overheat.
Q.E.D.
I rest my case.

ok when you say viscous fan you mean the shiny grill thing dont ya (excuse me im no mechanic only diy lol:thumbs) well the little coil in the middle of the old one was rusty as compared to the new which was shiny ,so thats the only difference i noticed .:doh

 

[leafy1]

ok when you say viscous fan you mean the shiny grill thing dont ya (excuse me im no mechanic only diy lol:thumbs) well the little coil in the middle of the old one was rusty as compared to the new which was shiny ,so thats the only difference i noticed .:doh

Spin the fan in your hand as you should feel a little bit of resistance..most of the viscous fans I have tried will run pretty free after a few turns .If it spins all the time very freely then it won't be of much use.

The waterpump leaks when the seals fail (There is normally a small hole underneath and it's in a difficult place to see for leaks,it's not the gasket that fails)

 

[lacroupade]

ok when you say viscous fan you mean the shiny grill thing dont ya (excuse me im no mechanic only diy lol:thumbs) well the little coil in the middle of the old one was rusty as compared to the new which was shiny ,so thats the only difference i noticed .:doh

No the actual cooling fan in front of the main rad.

Its stopped the leak so I wouldn't fret.....so long as the temp needle is at 12 o'clock when its warmed up then jobs done.

 

[solarman216]

the viscous hub will drive the fan for a few seconds after startup then freewheel, as temperature rises the coil spring (bi metalic) will open a valve allowing the viscous fluid to drive the fan, unless the hub has lost its fluid then the spring is usually at fault, so externally it is not easy to tell good from bad, Rick

 

[pablo0874]

No the actual cooling fan in front of the main rad.

Its stopped the leak so I wouldn't fret.....so long as the temp needle is at 12 o'clock when its warmed up then jobs done.

wen u say 12 0clock you mean halfway up the guage ??
see mines always ran about 2 to 3 mm from the bottom of the guage and wen towing a heavy caravan reached just a bit above that and makes that loud noiise when taking off in low gears after working hard you know that noise when you start from cold and it goes off after about you hit third ,is that the fan ?the noise i mean

 

[Dynamics]

the viscous hub will drive the fan for a few seconds after startup then freewheel, as temperature rises the coil spring (bi metalic) will open a valve allowing the viscous fluid to drive the fan, unless the hub has lost its fluid then the spring is usually at fault, so externally it is not easy to tell good from bad, Rick

Here's a video ...

http://www.youtube.com/watch?v=wLnOs1mwrw8&NR=1

 

[solarman216]

Here's a video ...

http://www.youtube.com/watch?v=wLnOs1mwrw8&NR=1

Excellent, thank you, makes it easy to explain in future, Rick

 

[lacroupade]

wen u say 12 0clock you mean halfway up the guage ??
see mines always ran about 2 to 3 mm from the bottom of the guage and wen towing a heavy caravan reached just a bit above that and makes that loud noiise when taking off in low gears after working hard you know that noise when you start from cold and it goes off after about you hit third ,is that the fan ?the noise i mean

Is your gauge horizontal or vertical then? Most are horizontal so needle at normal running temp is in the 12 o clock position i.e. vertical, and should pretty much stay there unless under very serious load up a long hill in very hot weather.....if its a vertical gague then I guess 3 o clock....? But not seen one on a Terrano in the five I've had....?? Mind you, I may well be going mad here and thinking about another vehicle altogether LOL

 

[rustic]

Here's a video ...

http://www.youtube.com/watch?v=wLnOs1mwrw8&NR=1

Excellent video, well found, I wondered why and how they worked.

If these are new when supplied with the new water pump, then the replacement is very cheap. :clap

So do new Milner pumps have a viscous fan, or are they driven all the time? :nenau

 

[Terranical]

Is your gauge horizontal or vertical then? Most are horizontal so needle at normal running temp is in the 12 o clock position i.e. vertical, and should pretty much stay there unless under very serious load up a long hill in very hot weather.....if its a vertical gague then I guess 3 o clock....? But not seen one on a Terrano in the five I've had....?? Mind you, I may well be going mad here and thinking about another vehicle altogether LOL

The temp gauge on my '94 pre-intercooler T2 is vertical, just to the right of the speedo. Under normal running conditions the needle stays at around the 7 o'clock position - when climbing a longish hill it can rise to around the 10 o'clock position, particularly in the 35+ degree temps we're currently getting here in southern Spain.
Hope this clarifies the needle position thing!

 

[lacroupade]

The temp gauge on my '94 pre-intercooler T2 is vertical, just to the right of the speedo. Under normal running conditions the needle stays at around the 7 o'clock position - when climbing a longish hill it can rise to around the 10 o'clock position, particularly in the 35+ degree temps we're currently getting here in southern Spain.
Hope this clarifies the needle position thing!

Oh forgot you've got a MkI....and you're in Spain to boot LOL

Having said that, sounds like a flush of the cooling system some time might not go amiss.....I've towed a massive heavily laden twin-axle box trailer the length of France a few times and the needle barely crept above the middle position.....

 

[Dynamics]

particularly in the 35+ degree temps we're currently getting here in southern Spain.

If you've got any spare sun. Pop some in a PM please Mate...

 

[pablo0874]

Here's a video ...

http://www.youtube.com/watch?v=wLnOs1mwrw8&NR=1

thats excellent that that explains it i thought it was just a piece of metal that looked like it done something that explains the noise must be the fan spinninfg faster then cutting off :clap:clap:clap

 

[pablo0874]

Is your gauge horizontal or vertical then? Most are horizontal so needle at normal running temp is in the 12 o clock position i.e. vertical, and should pretty much stay there unless under very serious load up a long hill in very hot weather.....if its a vertical gague then I guess 3 o clock....? But not seen one on a Terrano in the five I've had....?? Mind you, I may well be going mad here and thinking about another vehicle altogether LOL

mines vertical and works needle on the left of guage mine operates normal at well if it were the left half of a clock from 6 to 12 mine would operate at 7 oclock but when towing 8 oclock ,however when pump was broke it was operate ing at 9 and eventually hitting 11 if that makes sense ,lol:naughty

 

[fridgman]

Keeping relevant to the thread, where does the viscous coupling draw it's heat from to operate the fluid clutch?

 

[rustic]

Keeping relevant to the thread, where does the viscous coupling draw it's heat from to operate the fluid clutch?

It's attached to the water pump that pumps hot water....:thumb2