3000m . water pressure cap location

[laikathedog]

Guys

I have a 3000m which just overheated by spraying coolant out of the pressure cap on my OVERFLOW tank.

Should the pressure cap be on the swirl pot or the overflow ?

At the moment I have a plain cap in my swirl pot

And why did it blow at "only" 120 degrees ?

[phillpot]

What pressure cap do you have?

With a 15psi cap the water will indeed boil at 120 degrees!

[prideaux]

laikathedog said:

Guys

I have a 3000m which just overheated by spraying coolant out of the pressure cap on my OVERFLOW tank.

Should the pressure cap be on the swirl pot or the overflow ?

At the moment I have a plain cap in my swirl pot

And why did it blow at "only" 120 degrees ?

Pressure cap on the overflow tank.
Fit Evans and you wont worry about what pressure cap you have fitted .
A

[oliverb205]

But if you are sticking with old skool water it should be a 13psi cap on the overflow bottle with a non pressurised cap on the swirl pot.

Oliver.

[plasticpig72]

i think you have just opened a bag of worms!!!!!

[Adrian@]

Worms...not on the classic forum, (we like to leave that over in the 'S' forum) we know which cap goes where, and that said, it would normally be as Oliver say's.
Adrian@

[laikathedog]

good news is that the misfire i developed at 120 degrees was caused by the cap venting steam straight at the dizzy and filling it with condensation…

all cleaned and running again.

but while i have opened the can;

is there any value in an oil cooler setup ?

i have the low profile rad in my 3000m that goes under the spare wheel.
i have a pair of SUCK spal fans set to come on at 80 degrees and i happen to still have my old original push fan in place (i was intending to disconnect it !)
I have a 55amp alternator
i have a full size numberplate blocking the lower grill…. i am going to remove it and fit an illegal small numberplate

I have just put my original fixed fan back on the pulley….

[Cerberus90]

If you've got a pair of Spal fans on the rad, then I wouldn't bother with the fan on the engine, sapping power for no real gain.

Before fitting an oil cooler, find out what temp the oil runs at, no point adding all those potential leak points if it's not needed.

[GadgeS3C]

You shouldn't need any more than the pair of fans on the rad. I'd take off the push fan and wouldn't have the engine driven fan. If it's overheating then find out the cause.

Agree with Thomas - cooling the oil is a different issue.

Our 3000M has survived Le Mans temperatures and traffic jams with a couple of 8" fans.

[Adrian@]

Find out why it is running SO hot first...granted that the system vented previously, were the caps holding pressure? Is/was the system running under pressure correctly? Has the the voltage stabiliser got it's earth and running the gauges (temp/fuel) correctly? Get rid of the hot wire version and install a electronic version anyway. Is the water pump a cheap tin impellor (thrashing water) or a proper cast item (pumping water), purchase a non contact temp gauge, so that you can take reading across the radiator to check the flow and check exhaust/block for temps and hot spots in the block.
Adrian@

[whitewolf]

I'm running twin 8" fans, on a kenlowe sensor, new thermostatand recored radiator. All fine 4 years on.


However recently I changed my resistor for a digital type, and new earths to all of the guages. temp guage is a littlw higher then before and when tested with an infra-red thermometer all is still ok.



Same rad as OP, money in a good cooling system is a smart move.

[ausi steve]

Here in Perth Aust [a hot climate]I have a low radiator with two pull electric fans, no heating problems. I still have the original electric fan & only use it if stuck in traffic on a hot day, this fan not only blows through the radiator but causes air to flow across the entire engine. It is remarkable the amount of hot air you can feel coming from the car. My advice is keep the original fan & keep it as a backup when needed.
Steve

[laikathedog]

quick update

i put the spare wheel back in, put the original fan back on the pulley and removed the numberplate. last weekend i did the same journey.

the section of high speed motorway that caused the temp rise to just under 120 last time, this time i was running at 90 approaching the motorway (usually runs at 90 when warmed up) then it went down to 80 during high speed which was good to see and expected as I had opened up the grill by removing the numberplate and directed all air through the rad by putting the spare wheel back on.

I then sat in m25 traffic for a while which saw me rise to about 100, then under way it went back dow to 90.

then…

i have a short country lane end to my journey of 4 or 5 miles which was "spirited", I came to a junction and into a 30mph section where my temp jumped back up to 110 ish…. and when i got home i noticed that i was venting water again from the NEW 13psi (.9bar) pressure cap, after a minute or so it stopped as the pressure had dropped… but i still have a problem ! and need to clean up under the bonnet again !

to answer adrian: i have an electronic voltage stabiliser, a good cast water pump, new thermostat and a laser temp gauge is my next step ( next a saturday)

[bluezeeland]

Acknowledging the fact that the low rad is limited in effectivity......

Going on the fact that the waterways and fans are all clear and working as they should (?)

Both weak mixtures (air/fuel, iow the carb) and wrong ignition timing (both initial and pre) can be a source of elevated engine temps

The temp levels you are mentioning are just to high, even in high ambiants, and will damage the engine in the longer run

Think some indepth inspection is required here

btw; an oil cooler will only 'cure' matters temporarily (whilst costing a few bob.....)

[Hansoplast]

To add to list of E, also the valve clearance (to tight) can cause overheating.

Oil cooler is for the boys that like to look fast.

Hans

[bluezeeland]

Agreeing with Hans, allthough I do not know who or what 'E' is......

Another cause could be the .... head gasket.......