Here's a new one running too cold

[Phaeton]

Well I reckon that now I've moved my rad to the outside of the frame, removed the mechanical fan & replaced it with a sucking electrical fan that I'm running too cool. As I'm driving the temperature goes up to the 80 degrees mark I can then watch the termostat open & the temperature comes back down to nearly 50, goes up, comes back down again. The fan switch is on the top hose just after the thermostat & set to the highest temp it can be 90. That does cut in after the thermosat opens but even after a spirited run you can put your hand on the rad anywhere apart from the top inch or so. So am I cooling too much? is there an optimum temperature that the water should be going back into the engine at. If it's too hot then it's obviously not going to cool the engine enough & overheating will occur. But if it's too cold (can it be too cold) is it not letting the engine run at it's best efficiency?

I was thinling of moving the rad switch onto the bottom pipe & setting that at 60-70 degrees this would allow the whole system to warm up correctly.

Thoughts or actual knowledge anybody?

Alan...

 

[iank]

Surely it's the thermostats job to control the temp. Sounds like your temp sender/gauge are wrong if the thermostat is working properly (or the temp sender isn't measuring engine temp but instead measuring radiator temp?).

 

[Phaeton]

Surely it's the thermostats job to control the temp. Sounds like your temp sender/gauge are wrong if the thermostat is working properly (or the temp sender isn't measuring engine temp but instead measuring radiator temp?).

I think the thermostat is controlling the temperature,

Engine warms up & opens thermostat, which allows cold water to enter bottom of engine, because hot water is now in top hose the fan cuts in. Cold water cools engine down brings gauge down & closes thermostat, temperature then rises & we start all over again.

Alan...

 

[mines got a bonnet]

wot temp stat you got? have you got a bypass hose type head? have you drilled the two 3/16" holes in the stat ( a david vizard recomendation if you don't have a bypass hose). if your stat has a giggle pin in the flange then you don't need the two additional holes.

the best stat is usually the 74 degree

 

[Phaeton]

Think the stat is an 85, not bypass on the pump, but running a sandwich plate off under the stat which goes throug hheater matrix & back into bottom hose.

Alan...

 

[mines got a bonnet]

i would maybe try a 74. will open sooner and maybe smooth out your temp control. might have lower nominal temp but might be more stable. is the sandwich plate a metro thing?

drilling the holes will not make things any worse either. bit of a fail safe as well for the day that the thermostat decides not to open when it should, you will still get some water flowing to the lower section of the engine.

not an expert but it has worked for me on my minis. i currently have one of those brass collars replacing the thermostat in my buggy. takes a bit longer to heat up, but all my journeys seem to be 40 miles +, so this doesn't really bother me.

 

[esdebe]

I had a pump with the bypass on it and when I swaped my head for a UL converted one, I had to drill the hole for the bypass on the head so I could connect it up. However if you don't have a bypass on the pump you could feed the bypass back to the top hose (I think). With your sandwich plate, is the thermostat above it or below it? Having it below would mean your heater matrix works like a bypass.

 

[Phaeton]

Got a heater matrix in as a bypass. Today moved the temp switch from the top hose to the bottom hose & dropped the switch on temp to 55 this seems to have sorted it out but haven't run it very far.

Alan...