I have posted a breif chat recently regarding an engine coolant temp problem i have been having on and off.

let me explain first that the engine has just been fitted with a new water pump, a new alloy 2 core radiator, a 160 degree F thermostat, all new hoses, fresh coolant and all new gaskets etc.

when driving the car in general traffic at speed over 30 km/h the engine temp is fine but as soon as i stop anywhere the temp rises after about 30 seconds. when the daytime temp is higher, 25 degrees of more, the engine temp is even more up and down.

i have this afternoon performed compression tests, cooling system pressure tests, exhaust gas tests (in cooling system) and the result of all these tests was normal. no exhaust gases are present in the cooling system, there are no pressure leaks in the cooling system and the engine compression tests were all 100% fine, no pressure leaks there either.

with the old single row radiator and old water pump i was sure they were the cause but after fitting the best (as far as a road car is concerned) cooling system bolt ons i could, alloy radiator, new pump, cooler thermostat etc, the engine is still getting hot when not moving.

It seems the origonal 11 blade yellow plastic fan blade is all sweet and working a treat. i did think this was at fault but it is pushing more than enough air. i have also checked three times that i have not fut the fan on backwards, and it is fitted correctly.

can anyone shed some light on this? is this normal?

i drive 1 hour each way to work every day, and while i am moving it is fine, but as soon as there is traffic and i have to stop the temp gets as high as 200 degrees F.

i plan on fitting a big thermo fan and an oil cooler in the next week or so.

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'66 BRG Morris Mini Deluxe 60HP ATW

Your 2 core alloy radiator.. how many fins/gills per inch does it have? If it's a UK type (8/inch IIRC), it'll be insufficient for our conditions. Oz ones have 14 (or is it 16?) fins/inch.

What pressure rating is your radiator cap?

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Simon

The adventures of an owner builder in the Tallarook Ranges

If you have not done it yet, check the gauge against a known thermometer.
An easy way is borrow mum's glass thermometer and test the top tank water during warmup (leave rad cap off).

You may be surprised, our S replica's gauge was getting real near the H mark, but the water was only 74C actual temp.

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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.

I wouldnt think the radiator cap is related unless it was losing water, which it isnt.

the radiator cap is new also. the radiator is an aussie one. its not a UK one.

i will be fitting an overflow bottle though as a nice extra. it is currently a non-recovery system.

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'66 BRG Morris Mini Deluxe 60HP ATW

yeh thanks for that. i have also checked that this afternoon. the guage is 5 degrees F less than actual temp. accurate enough for me though.

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'66 BRG Morris Mini Deluxe 60HP ATW

jester,,, it is actually quite normal for the engine temp to rise whilst stationary, it`s a dual action thing really,,, with the engine at idle there is very very little water movement (espeically if your idle is low) so with little water movement there is also very little heat dissipation from said water when said hot water is just sitting reletively still inside the block "absorbing" heat from the engine still

also the fan is traveling soo slow at this point that very little heat is transfered to the air from the rad gills

BUT!!! they ""normally"" will hit 3/4 on the guage (85-95cel-ish) sitting in traffic & then would "Normally" cool down once you`re traveling along again

a thermo fan will help """IF""" you lift the idle with the throttle pedal occasionally while you`re stuck in traffic, which will increase the water pump speed, move more water, helping all that hot water reach the rad for the thermo fan to actually do something good



edit--> also as a note of interest,,, the std cooper "S" owners manual will say that to help decrease engine temps when stuck in traffic it`s advisable to turn the heater & it`s fan on true.

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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.

Thanks matt. The radiator is the alloy one i bought from you recently. That reminds me a have a small shopping list right now. i'll give you a call tomorrow and order some bitz.

Cheers

Jason

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'66 BRG Morris Mini Deluxe 60HP ATW

ahhh,,, well obviously the radiator isn`t the problem then ey???

they cool our turbo injected Twin cam 16v moke so it will certainly cool almost any mini

let me know what you need when you`re ready mate, easy-peasy

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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.

thanks matt, yeh i never doubted the radiator. it is a million times better than the origonal. fitted really nicely aswell. looks sweet.

talk to you tomorrow.

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'66 BRG Morris Mini Deluxe 60HP ATW

Quite a valid point Matt.

jester99, have you checked that in fact the idle speed is high enough?

You might also want to try a different brand of thermostat.

It appears that the Gauge your using is Electric. I see that you have done some tests on it (in the workshop?). Try fitting a capillary gauge and going for a drive. Electric Gauges can do 'funny' things.

What engine are you running and what's it's state of tune?

Does it start OK from 'normal' operating temperature?

What type of water pump are you running and do you have the by-pass connected?

Does the Temperature ever 'Max Out' or just get a bit warmer when stationary?

How does the Temperature behave when you drive hard for a period?

Not sure that a Thermo Fan would be the way to go and while fitting of an oil cooler can be worthwhile, I don't think it would help much here.

I have found that if the Standard Mini Cooling System is in good order and this includes very very clean and rust free water jacket in the engine, then it can cope adequately with fairly 'hot' (perfance wise) engines, however they are marginal in that it does not take much to make them go 'off'.

Thanks guys. I will continue to play with it until its right.

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'66 BRG Morris Mini Deluxe 60HP ATW