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

[twisted]

Don't give up Ron! You have it sussed now, it will be fine. As mentioned its not Wednesday yet 

[fifer]

Stick at it , Ron .
For all it,s spitting has it ever let you down ?
A camel spits but it keeps going across the desert 
.
.

[andyrennison]

How you doing Rod?

[hunter]

Was thinking the the same.

[scannerzer]

the suspense is killing me 

[ROD]

So ,Im back on here after my little spat.Rennie pm'd me and I thought its time to come back!
 Well,I fitted the said tank etc as I described. I tested it fully (as I thought) up and down the by pass,high speeds,low speeds etc . Seemed ok. So off we went to France on Saturday.We came back on Sunday,gutted isnt the word!...So......... On the way down to Folkestone it started to spit out of the overflow on the new expansion bottle. So it became,pull over,cool down and off we go again,over and over again.It happens just as the temp reaches a little over 100c. guage seems accurate as I replaced it and sender as a precaution at the same time as bottle.
  100 miles into France same thing. If the revs are held constant ,say at 50mph,the temp climbs. If I back off the throttle a little eg down hill for a bit the temp will drop a little below to around 90 degrees.Ive tried to find out what temp Reliants generally run at,but cant find any info,and I cant see it in the handbook.I think the fan (suzuki bike,its a puller behind the rad) isnt big enuf to cope with the higher temps,cos it will sit all day ticking over at about 80 degrees. If I slow in a traffic jam to say a crawl,the temp will drop!
  The top hose runs downhill to the rad (about 2 1/2" difference) so Ive t'd the bottle in to the top hose.The hose is about the same diam as the reliant top hose,and the outlet on the bottle is exactly level with the top hose. The smaller diam pipe to the top of the bottle (see prev description on other post) Ive t'd into the pipe running from back of head to w/pump.The engine revs determine how much water pumps through this pipe and 'waterfalls' into the bottle.Im wondering if the bottle has to be higher? I dont appear to have any air bubble stuck in the system. Today I leaned out the carb a little as there was a little smoke coming out of the exhaust on start up. Timing appears ok.i have a zero rad cap and a 7lb cap on the expansion bottleI may have to get a larger kenlowe type fan to push air through the rad. I think this will cure it.Im actually wondering how much air goes through the rad,as the forks are as wide as the rad is,and maybe they are shielding the rad a lot.And of course eventually I will tidy up the bottle pipe work ,cos it looks absolutely heath robinson with Jubilee clips all over it.

[Manky Monkey]

Rod, you say the coolant "waterfalls" into the bottle? Am I missing something here?
If it's set up as an expansion system, then there should be a hose going down into the bottom of the bottle, with a small amount of coolant in there so that the end of the hose is always in the water. As the coolant in the radiator heats up, it expands & runs into the bottle. Then as it cools, it's drawn back into the rad'. 

[andyrennison]

Fifers your man on this, but I thought the circ temp should be within a few degrees of the stat temp. The fact it drops when not under load seems to me exactly what you say, the fan ain't man enough.

[andyrennison]

....... i have a zero rad cap and a 7lb cap on the expansion .......

So which cap will open first ? Rad cap I think. Where does the overflow from the rad go to?

[ROD]

rad cap is  zero = therefore it is sealed.
 overflow from rad is blocked off as well.
 When it overheats,the coolant comes out from an overflow stub just below the bottle cap. (looks like a rad neck)
 
 It waterfalls in,as it is t'd into the pipe from front to back of engine. I thought this was a little odd,but Im told that this pipe from the bottle is normally connected to somewhere on the block of 'other' engines
 As far as I can tell,the large diam hose from bottom of bottle to the rad top hose is the one that the fluid expands up into the bottle.
 
 ive just read another article which says connect the large diam pie from bottom of bottle into the BOTTOM hose,not the top as Ive done! All this seems like a secret science to me! Angle grinder awaits!
 
 what if I do away with the thermostat?

[Manky Monkey]

I'd recommend having a chat with Kev, (Kapri), before you start chopping things up. He spent a lot of his working life in the radiator business.

[ROD]

He has given some good advice on this thread,which I have followed exactly,but I still dont know whether Ive done something wrong in the process..

[terry t]

do a diagram of the your setup. rad and water bottle in relation to engine positions so we can see whats what

[andyrennison]

Rod. I have read and looked at every post on your thread - yes 60 pages. Sadly most of your pics don't appear, there are 3 and all show your rad, but not your fan. You seemed to be having overheating problems BEFORE your engine rebuild if I read the posts right. Can you get lots of pics of your setup, in particular at right angles to the rad to show the clearance between the rad and the fan, and also face on to the fan against the rad. I think the "game is afoot" Watson

[andyrennison]

 what if I do away with the thermostat?

I don't think that will make much difference, so long as you are SURE it is opening. In my experience a bust stat will lead to overheating whatever the driving conditions. We used to get around that by turning the heater on full pelt, as it cooled the engine despite the stat being open. Oh happy days in the sun in Cumbria sweltering while driving aside the lakes. Then a £2.00 stat fixed the problem. (that was another diagnostic in the "old days" - water temp rising and heater blowing cold = out of water )

If you are not sure it is opening try without while we have the hot weather with us. What effect do you get? That way you can rule it out at zero cost