Thread: Radiator replacement

Originally Posted by 350RRC

Thermostats can flow too much so the coolant doesn't spend enough time in the radiator to cool as much as it should or could.

That’s an old wives tale. A heat exchanger will exchange as much heat as it can. The faster the coolant flow and therefore the lower the temperature difference, the better it works. Same as coolant in the block. Look up the log mean temperature difference (LMTD) and do the sums. If it’s faster in the radiator it’s faster in the block. Yes, slower slow will mean a larger temperature gradient, but it means the coolant in the block picks up the same.

Also, faster flow means more turbulence and that generally leads to better heat transfer.

Originally Posted by Meccles

Its a Fenix ally radiator not brass a later model 4 door unit that I suspect is partly blocked. I got temps down a bit with richening mixture but want to go cooler. Thermostat is the same unit as on old engine.
I'm very tempted to just buy a new 4 row unit with fans and shroud as mine is a bit of a bitsa.
I like seeing gauges in the middle or towards cool end not up the other way.

If you are talking the factory gauge, you could be running over 100degrees. That crappy gauge is normalised.... so its readings are almost meaningless. You need a proper gauge so you can see what is actually going on!

towing up long climbs in low gears I've had the accurate aftermarket gauge at about 100degrees .... the factory one still showed middle of the scale normal. Do not trust it!!!!!

seeya
Shane L.

My gauges are all Dakota Digital with Dakota digital sensors. They are bang on.
thank for the concern though but all Lucas instruments/gauges/senders have long gone

There's a new radiator arrived hope to fit it later this week. Along with new A/c condenser as there was an "oops oh bugger hissing moment" when fitting oil cooler. I took protective measures but they were inadequate so lost my lively ac

lovely

This is my instrument cluster I added oil temp BIM it comes with its own sensors

VHX-1018: Universal 4.4" x 11.4" Rounded Rectangle, Analog VHX Instrument

Originally Posted by BradC

That’s an old wives tale. A heat exchanger will exchange as much heat as it can. The faster the coolant flow and therefore the lower the temperature difference, the better it works. Same as coolant in the block. Look up the log mean temperature difference (LMTD) and do the sums. If it’s faster in the radiator it’s faster in the block. Yes, slower slow will mean a larger temperature gradient, but it means the coolant in the block picks up the same.

Also, faster flow means more turbulence and that generally leads to better heat transfer.

It's interesting that the throat size of every thermostat I've seen is smaller than the inside diameter of the radiator hoses.

Apparently one of the reasons this is done is to increase pressure around the vanes in the water pump slightly to reduce the risk of cavitation.

It's many years since I read a detailed article about thermostats and overheating and the author may have come to the wrong conclusion about why an overheating issue was solved by changing the thermostat to one that was slightly more restrictive.

DL

Fitted new Chinese four row radiator the core was a bit thicker than my old Fenix unit. The old unit was on its way out there was evidence of cracking starting on some bits of core so well worth replacing.
The new unit is working well BUT fans as supplied are pretty naff they are Spal copies but seem to flow bugger all. In Brissy heat/traffic jam I can see better fans would be helpful. A very simple job to remove the Chinese units from shroud and fit some Maradyne or Spal units. So am happy with this