Hi there guys,

So it turns out Rowan very much dislikes idling on hot days. It seems as though the current mechanical fan doesn't cool the radiator down efficiently enough to keep the engine at a suitable temperature. The result? Turning the car off at every possible moment, or the car spits the dummy (and coolant).

My query. Has anybody here ever somehow added an additional 12v radiator fan to piggyback the standardd mechanical fan, activated by a switch in the cabin?

And or, is there a way to keep the engine cool enough without doing this? I.e. manually idling the car at 2000rpm to get the fan spinning quicker?

Thanks!
Dan.

The fan is not the problem.
Find the real overheating problem and fix it.

If the fan isn't the problem, another issue comes to mind. Radiator is filled with Brown creamy goop (water not flowing efficiently enough).. car doesn't shoot smoke at all, runs very smoothly so I ruled gasket out of the equation.. Might need a nice flush, coolant hasn't been changed in countless years I guess. Will do so when I get a chance and report back with results.

Thanks for the swift reply.

Dan.

Well there's the problem! Yes, the radiator needs cleaning.

A really good thing to do for your engine is to take the radiator out and have it tanked and rodded out by a radiator shop. They take the top and bottom tanks off the rad and rod it through to remove all the scale that will have built up from the goop.

50 year old radiators work like new when this is done, and it only costs about 80 bucks at a proper radiator place like Natrad workshops.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I'd stay away from the big chains. Last time I asked my nearest Natrad it was $140+ for a rod out and clean.
My local Korean rad man in Blacktown charges $90 now, I had one done last month.
It might be cheaper if you live out in the sticks...

ps. if they say it needs a recore forget it, you are talking~$400 for that. Might as well buy a new Minispares super 2 core then.

Stay away from the cheapo UK? 3 cores, as they only have about 8 fins/inch. Oz ones have 16.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

If You car is fitted with a heater, it would be a very good idea to flush the heater matrix
as well as your Radiator

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" A Hundred Years From Now It will not Matter what my Bank Acount Was,
The Sort Of House I Lived in, Or The Kind Of Car I drove ... But The World May Be A Better Place
Because I was Once Important In The Life Of A Child"

if you know anyone with a Rover mini, have a look at their set up, mine is both fans, normal and elec. because I have A/C as well, never a problem even last week with 40c in traffic with a/c running, sat exactly in the middle, purrfect.....touch wood

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Also make sure the rubber strip is on the radiator cowling as this stops hot air re-entering the engine bay. It seems like a trivial part but it makes a huge difference(around 20 per cent!!). For the sake of a few bucks spent at clark rubber, your mini will be cooler and better off.

Hooroo

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Rob Forsyth
Miniot!!

The others are right.

But in the short term I would just disconnect the top radiator hose and the heater hose that feeds into the other side of the head. Hold the garden hose in one of the pipes as tight as i could with my hand and turn the hose on, leave it there till the water coming out is clear and then do the other way around.

If you can it might be worthwhile undoing the bolt in the back of the block the drain plug (sometimes nothing comes out though - nothing came out in my gt and it doesnt come anywhere near overheating) This will allow you the give it an even better clean

Brenton

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The wheelarch is a low pressure area compared to the engine bay when you are moving, IMO that mangy rubber strip does bugger all. BL UK got rid of it, and the whole shroud, around 1980... and their cooling didn't suffer.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

more than a couple of things happen on idle to help your engine run high in temp

"If",,, (as you say you have ruled out head-gasket issues) then "IF" that`s true (& it`s a big "IF") so if there is no headgasket issues & all else is in perfect working order,,, then go to the "Firstly" paragraph

If not,,, & if you think there really are other issues like head-gasket &/or lean carby mixtures &/or retarded ignition timing &/or any combination of any/all of the above... then refer to repairing "head gasket & other overheating related issues" paragraph before proceeding any further


so...

"Firstly"--> the water pump is barely turning any water over at all on idle,,, so what i suggest is to rip the water pump out,,, physically go to your mini specialist,,, annoy the phark out of them to physically inspect each water-pump that they have in stock & buy the one with the biggest impeller but also the one that has it`s impeller fitted closest to the alloy pump housing.

there`s a gap on them all, but the one with the least gap is going to work far better that the one with the largest gap

2ndly--> the fan doesn`t actually do much fanning on idle either,,,, so again i`d make sure that the fan is actually fitted the right way round,,, & also that it`s fan blades actually line up with the lip on the fan shroud

if the fan is too far inside the rad shroud ,,, or not far enough in,,, then it won`t push as much air as it should

3rdly--> Simply because the BMC factory knew about the stationary idling heating-up issues inherent in their design, they actually made it known in their owners manual to turn the heater on in hot climate while idling stationary,,, sounds funny hey? but it`s true!!!... so it was known from the factory on day one that idling a mini will cause it`s engine temp to rise somewhat... however, this generally means it will climb to about 3/4 temp & stay there--> providing all else is in good order))), no leaky head-gaskets, no cracked heads & in perfect state of tune (IE: not lean or retarded)

So,,, what we do is--> make sure there are no headgasket issue 9Don`t just guess,,, diagnose it properly) we also make sure there are no running lean mixtures or air leaks or ignition timing retarded or any other tune related issues that can cause running hot problems... we also block-off (Modify the cooling system) & make the little water outlet (heater take-off at the back end of the head) & take a hose from there & make a fitting fit into the top tank of the radiator (probably cost about $10 at your local radiator shop) & put your new by-pass hose from the back of the head into that new fitting in the top tank of the radiator

this will do wonders to your cooling system in a number of depts

we also make sure of item 'firstly" & item "2ndly" too,,, the 3rdly one can be addressed by adding another heater matrix to the back end of the head (where the heater take-off usually is) however we find that not necessary on our engines,,, but many other people do use it.

& then 4thly-> you can add an electric thermo fan to the underside of the passengers side inner mudguard ,,, generally with the std inner-guard panel still in place makes for a fairly weak suction tho,,, so removal of that grille section of the inner guard & mounting your new thermo fan as close to the radiator as possible is going to be far more effective than just whacking it onto the outside of that grille yeah?

I like the thermo-fan idea however correct placement, quality insulated mountings, & a decent control unit are a must

there are many ways to stuff a kitten,,, try the best way first (it`s usually the simplest)

& people--> just so we are on the same page here,,,,generally speaking , a blocked (or semi-blocked) radiator will cause overheating while driving along at higher rpms (like high-way use) more-so than on idle,,, altho i`m not going to argue that it may ( & sometimes does) cause overheating on idle,,, but more than likely the owner would normally suggest an over-heating situation while motoring down the high-way

hope this helps,,,

& yes John i know, you`re right... i will keep doing this hey

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

All good advice. I remember the good old days with my 1100. Coolant was always brown and always had overheating issues.

Since the 1330 rebuild with rust and crap taken out of the block and running a nice and clean radiator, she runs too cold in winter time. Takes FOREVER to heat up properly and even then at speed she's too cool. I had to change over to a hotter thermostat just to get it up to proper running temps...

And I don't run anything special, just the original type metal fan (the one with many blades) and a stock radiator... So yes, sort the actual problem out, which sounds like rusty radiator and or block. Give it a good flush out etc as per advice above

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Lillee - 1969 Morris Mini K