Pre-cat Radiator Airflow

Hello All,

Just getting used to my '92 pre-cat and all its 'characteristics' ;-)

I have a question for fellow pre-cat owners.

I believe my cooling system is spot-on. Thermostat fine, temp gauge steady as a rock 90-95, fans cut in, heater toasty warm, absolutely no airlocks.

So whats the problem then?

Well, I'm used to having a car that once up to speed (40mph +), the temp needle drops to whatever the thermostat regulates at. With mine, the temp needle stays at 90-95 and occasionally the cooling fans cut in whilst cruising. I know this because my headlamps and volt gauge take a hit when they cut in.

Why are my fans occasionally cutting in when driving along at speed? Is it a characteristic of the pre-cat nose with the little letterbox under the numberplate?

I have shone a torch through the rad and the fins are all in order, not bent or blocked. I don't believe the radiator to have blocked cores. Its the first time I have owned a car with a radiator lent over at such an angle - perhaps I'm worrying about nothing.

I have just purchased 'The Griffith Story' and there is a bit in there about struggling for air flow and different designs around the leading edge of the bonnet. Indeed, the front nose was modified for the 500.

Just seeking other peoples experiences before I declare 'faulty'.

Sincerest Regards,

Jay.

Hi Frank - new coolant pump from Rimmer Bros, new genuine Land Rover thermostat. Block, heater matrix and rad flushed (including the inlet manifold valley pipes). Good condition (still blue) coolant ejected right from the start of the flushing procedure. New SAMCO hoses all round including heater matrix supply/return. Comma anti-freeze mixed 50/50 with distilled water. System bled out perfect with all bleed screws. Thermostat opens just fine. Brand new, twin SPAL fans operate as normal, for normal time intervals. Rock steady temp 90-95, heater matrix nice and toasty. Cogged V-belt correctly tensioned. Coolant level bob-on. Radiator in perfect visual condition. All the things you have asked me to check are bonafide overheating root-causes. Mine does not overheat. As far as I am aware, to the best of my knowledge, my cooling system is in top shape and has no faults. I just want to eliminate cooling fan operation whilst cruising.

Steve - thanks. I'm really interested in this splitter for a pre-cat nose. Was it factory fit? I don't appear to have one. Many people here have mentioned it. If it *is* factory, I will obviously have to make one. Does anyone have a picture of one, or is there a pre-cat in Cambridgeshire that I can compare with over a pint?

Thanks in advance,

Jay

So, just a bit of an update. Firstly I followed the advice of Griffdude and purchased an IR thermometer from Machine Mart. I knew these existed but shocked at how much the price had come down. For £28 its just worth having in your toolbox I think. Temperatures across the radiator just fine, no cold spots.



On that basis, I then set about making these splitters. I purchased a length of semi-square section OSMA guttering and cut it down with a circular saw table.





I have owned many high performance cars over the years, but I have never visited a builders merchant quite so much for any of them!

I fitted two, one at the trailing edge of the air intake just making a little lip, and the other at the rear which matches the OE principle and causes an engine compartment depression.





I did a long run down to Stansted on the M11 and temperatures have been drastically reduced. My cooling fans no longer cut in when cruising. Difficult to quantify, but I would say 5mm lower needle height on the gauge. Quite incredible really. I would say that my coolant temperature when cruising is now regulated by the thermostat partially closing - which is just what I want.

Thanks for highlighting this issue.

Regards,

Jay.