11 replies to this topic

[Chris.Williams]

A friend of mine brought mini 12G940 metro head and fitted it to his 1275, non bypass motor.
When I had it, it was running normal temps. Since he has fitted it, it runs cold, I mean cold, 57c on a digital thermometer titled inside the top hose.
82c on the head itself and 70c on the top hose after shut down.
He has, of course, blanked his water pump bypass, and fitted a thermostat (88c) with holes drilled to allow water to flow.
What could be causing this? He has no heater tap, just an open circuit.
Help please.

[nicklouse]

drilled too many holes. you only need the one small one that should already be there. it is just not getting up to temp.

[Chris.Williams]

He tried with no holes, didn't help......hence the issue

[nicklouse]

how do you mean did not help? 

 

that tells me nothing.

[Chris.Williams]

He changed to a thermostat with no holes, engine still runs cold, no difference from running the thermostat with holes.

[racingbob]

i have the same. i now run a revotech fan and single blade metal fan however a 120 watt fan would be better on realy hot days or a second single blade. in winter I cover the grill or take off the single blade

[timmy850]

Where is the coolant going from the heater takeoff? 

[Chris.Williams]

Where is the coolant going from the heater takeoff?

Through his heater......he doesn’t have a heater tap is all. It just flows all the time

[timmy850]

You shouldn't need any additional bypass if the heater is connected 100% of the time. Does the heater blow nice and hot? The heater matrix will be acting as an auxiliary radiator and possibly overcooling?

[Chris.Williams]

You shouldn't need any additional bypass if the heater is connected 100% of the time. Does the heater blow nice and hot? The heater matrix will be acting as an auxiliary radiator and possibly overcooling?

He now has a standard, undrilled stat, still sunning cool. His last head had the bypass & the same heater hose setup, ran normal temps.
Only thing that has changed is the head, which was on my engine and ran normal temps.
Confused much??

[timmy850]

The standard bypass gets the hot coolant from the top of the engine and sucks it straight back into the block and bypasses the radiator, which means it'll heat up quicker. It also means the coolant is flowing past the thermostat

 

Having the heater tap side on 100% and a full thermostat means the coolant flow will all be going out the other side of the head and not flowing on the thermostat side of the engine?

[Retroman]

A heater will drop the temp by probably over 5 degrees

 

I have run an oil cooler stat in heater hoses so it only comes in when needed.