Bleedin' radiator! HELP/discuss pls......

[terry t]

has the water pump impeller come loose on the shaft ?

i asked if the pump had been checked back on page 7  Mike
is the engine reaching the same sort of tempeture as the rad. as said before may be a block or air trapped in the block.

As you have tried most things altering pipe work, fitting of expansion bottle,extra fan, how about taking the rad off and setting it up in a tempory possition along side of the engine so the top of the rad is higher than the thermostat housing and letting it tick over checking the temp on rad and block until it reaches max temp

[Olds]

You beat me to it Terry.
Was going to say temporarily dump all the non standard piping, lash up the rad so its at the correct height correct and see what happens.
Wonder if there is room to fit the rad inside the front frame tubes if it cant go higher outside?

[terry t]

You beat me to it Terry.
Was going to say temporarily dump all the non standard piping, lash up the rad so its at the correct height correct and see what happens.
Wonder if there is room to fit the rad inside the front frame tubes if it cant go higher outside?

Dont think there is room for it to go in side Dave. it just another elmination job to see if cures the problem or need to look at the engine

[Rocket]

Don't know if this will help but a friend of mine races robins and a common problem is a buildup of rust around no4 liner restricting the flow of water when under load causing overheating, could this be the problem??

[Olds]

Dont think there is room for it to go in side Dave. it just another elmination job to see if cures the problem or need to look at the engine

I was just musing where to position the rad, if a raised rad worked.

Don't know if this will help but a friend of mine races robins and a common problem is a buildup of rust around no4 liner restricting the flow of water when under load causing overheating, could this be the problem??

Think Rod has replaced the liners, so that shouldn't be the problem.

[ROD]

Im b-a-c-k!
  thats whole lot of new posts to get through,thanks for all the interesting ideas/thoughts guys!
   Its been bugging me every single day whilst away.Heres a few answers to the Q's.........
 
   I did spent a lot of wonga on the engine ,new liners,pistons,skim head etc. Crank has a minor rear oil seal leak that I cant stop.I have 'burped' the engine after filling it with coolant (50/50 mix) a couple of times.
 
  Ive had the gas test done on the coolant..all ok.
 
 The system vents at about 105 degrees,cap is new its the correct long neck 7lb one (correct = 7lb as per orig system..long neck as per the right one for the bottle)
 
 The voltage to the gauge is a good point,which I'll check,but disregarding the gauge reading ,the system shouldnt vent so easily anyway.
 
 Running the engine stationary,I cant seem to get the temp up high enuf to make it vent...I suppose I could if I revved the nuts off it....was thinking about this whilst away.Im wondering if the airflow (forks are as wide as the rad roughly) isnt getting to the engine whilst on the move,just when the rad needs air to cool it more as speed increases (on the move as in constant 50 odd mph) but it doesnt need airflow at lower speeds as the fan is doing this.This was my orig theory as to why it needs another fan.
 
 Ive read elsewhere that the fan has to be pulling the air into an area of low(Ithink!) pressure or the air drawn away from rad cant get away.
 Water pump is/was brand new..havent checked if the impeller is slipping on the shaft..even if I removed the pump,it may not be slipping until it expands with the heat,then slips. Ive got the old one,I'll fit that and see.
 
 Cant fit rad inside tubes ,as too much to rebuild/cut away..I measured it..
 
 I cant even get the rad temporarily higher to drive it,as the forks will hit it on the turns.
 
 

[spanners]

here,s another thought , whip the water pump off and first check that the impeller looks the same as the spare/old pump ( aftermarket ones can be of poor manufacture) also check the impellor is for the same rotation yes there are reverse rotation pumps about .
then check the block where the water pump impellor sits for water wear marks / scoring  if at sometime in the past its been run with a busted bearing it can grind away at the block  resulting in excessive clearance between the impellor ond the block = less effiecent water pump ,
and yes impellors can come loose on the shaft when hot , but they generally end up sloppy fit..

[ROD]

Just looked at 2 other Reliant pumps I have,they cant be reverse flow, due to the way the vanes are cast.Both appear to have the pulley pressed on the shaft from the front. Looked at the trike one,it doesnt have any marks where the pulley is slipping on the shaft. Im presuming its key wayed ,or more than likely splined,although you cant see this on the end of the shaft.
 
  

[steve brock]

Are you using old hoses from the water pump I know my one seemed kinked and the bore was quite small .. Jus a thought

[scannerzer]

here,s another thought , whip the water pump off and first check that the impeller looks the same as the spare/old pump ( aftermarket ones can be of poor manufacture) also check the impellor is for the same rotation yes there are reverse rotation pumps about .

Spanner's is correct on this ,we had this problem with a classic mini one we supplied to a customer,turned out his original pump was the wrong one,fitted by a previous owner but it caused us some head scratching

[ROD]

Point taken. The new one came from a bonafide Reliant parts supplier (Reliant partsworld I think)
  Im going out there to do this right away.

[terry t]

Rod as you have the water drained down take the thermostat out and check to see if the hole at the back is clear. some gasket part block this and may get blocked



you can see the water way part blocked and it is no better if the gasket is turned over

[ROD]

I did notice that one of the head gaskets I bought had misaligned holes. Im pretty sure that I changed it for a better quality make and it was a lot better fit
 I'll check the stat hole .
 
 Just pulled water pump,compared it to the others I have,all look the same. Tried to move pulley on shaft . the shaft in the front pulley will move a bit ,but only with one end in a large vice,and the other with stiltsons and an 18" bar on it!
 
 UPDATE...
 Pulled the stat housing..hole is absolutely clear and crud free.
 
 THIS IS CRAZY!!!
 
 

[terry t]

I did notice that one of the head gaskets I bought had misaligned holes. Im pretty sure that I changed it for a better quality make and it was a lot better fit
 I'll check the stat hole .
 
 Just pulled water pump,compared it to the others I have,all look the same. Tried to move pulley on shaft . the shaft in the front pulley will move a bit ,but only with one end in a large vice,and the other with stiltsons and an 18" bar on it!
 
 UPDATE...
 Pulled the stat housing..hole is absolutely clear and crud free.
 
 THIS IS CRAZY!!!
 
 

what is the gap size between they pump fins and the water pump body.  plus how many fins are on the pump, have you got a photo of the pump

[ROD]

No photo.cant do until later. Gap size on 2 newer pumps,(one of which i just took off),plus  a third pump,which had a leak,is all .50mm. 6 vanes on all,the vanes on the newer ones are thicker..about 5mm/6mm,the older one is around 4mm.The vanes on the older pump look at dead 90 degrees,the newer pumps look VERY SLIGHTLY off 90 degrees.
 
 Reminder.......I was getting a temp difference on the rad of about 10 degrees top to bottom(very difficult to measure accurately even with the digi thermometer),after a hard run,so that must show that I am getting cooling?But maybe the wrong 10 degree "window" and needs more cooling?