Idle temp.

[rdssdi]

I have just installed a new 180 degree F thermostat and a new temperature sender. I also topped the cooling system at the rad cap and added coolant to the recovery bottle.

Driving around the gauge stays at 90 degrees C but at idle it continues to around 115 C and even with the electric fan running it will not go down in temperature.

I have a custom alloy radiator with a pusher electric fan. There is some air passing through the rad at idle but most "bounces" off the radiator face and does not get through.

Is this normal? Could the fin spacing be too tight as to impede the fan air flow?

Any suggestions?

Thanks

Bob

[CBUEB1771]

Did the engine run cooler before installing the aluminum radiator? What ambient temperature are you driving in? Is the aluminum radiator in the standard location or did you push it forward into the nose? I suspect you may need to block off any openings between the perimeter of the radiator and the body shell/front crossmember. The flow induced by the electric fan may be largely escaping around the perimeter of the radiator. Underway, the flow rate of air entering the nose will be greater than that induced by the fan at idle and cooling will improve. Blocking all of the "escape routes" made a big difference to cooling of my +2.

[rdssdi]

I never ran the engine with the OEM rad. The car was not running when I purchased it for restoration.

The replacement alloy radiator is in the same location and of the same width and height as OEM using the same mounting points. The core is a bit deeper.

There is a small opening where the electric fan shroud meets the radiator fins. I will use soft foam or rubber ti seal this area.

Of primary concern is the actual CFM specifications. The 10" perma cool fan I am using is 1250 CFM. This was the highest rating I could find in a 10" diameter fan. Perma cool suggests 1600 cfm for 4 cylinder engines. This dilemma is compounded by the fact that in pusher configuration there is a 20 percent loss over a puller configuration. That translates to 1950 cfm minimum for a pusher configuration and a 4 cylinder engine. The fan shroud on my 10" electric fan fits from top header tank weld seam to the bottom header tank weld seam. There is no room for larger.

With the small area of the radiator I cannot see how I could achieve such a rating.

Any suggestions?
It does seem unlikely that the original pusher electric fan on the =2 was anywhere near 1250 cfm. I doubt the two bladed metal fan attached to the water pump pulley did much at idle or ant other speed.


Bob

[rdssdi]

I ran the engine today. Short drive then idle at rest.

Temperature rose to 115 C at idle. When I shut down motor it popped through exhaust and when I turned key to ignition it seemed like the engine wanted to start by itself. No starter just a small cylinder ignition or such. Very strange.

Next I will check timing. What is next?

Oh. besides e-bay.

Bob

[redelan64]

Hi Bob,

I have an S1 Elan 26/3800 with 11? pusher Spahl fan ? 80 deg C thermostat and early standard big tank radiator and core. I had to fit fill in panels beside the rad to close the gaps and put a foam strip across the bonnet to seal the top of the radiator.

Absolutely perfect temp control on the hot 38 deg C summer days in Australia with around 135 bhp (Webers).
Also runs at least thermostat temp in cooler winter time.

I have also owned and "sorted" a few +2 Elans since 1974.
Your +2 will have closing panels beside radiator and foam seal on bonnet (Hood) to seal to the top of the radiator tank is a must.

At an idle the hot air can recirculate around to the fan again if you don?t.

The other thing to check is that you have the blade facing AND running in the correct direction.

Many people make the mistake of reversing the polarity to reverse the fan ? a blade will not work in reverse.

The manufacturer will probably show A or B sides on the blade so make sure the blade is on the motor shaft the right way for pusher (blower).

Think of an aeroplane wing ? blunt edge first.

Spacing of the blade to core face ? A fan blade works better and must run around 30 ? 40 mm away from the core face ? lessons learnt after many years on vehicle cooling system design shows this allows the fan to move the air rather than stall against the closer face.
I run (30 mm) 1 1/8? and therefore the plastic shroud edge is spaced about (20 mm) ?? away from the core face.

The only issue I have found is that if all the air entering the grill goes through the radiator, oil temp rises at high speed since there is no cool air to the sump. We have tried a rubber flap under the +2 radiator but the oil got too hot on high speed runs.

The +2 is similar to later Elans in that there is a gap below the radiator. I had to drill three holes ? 2? dia in the body panel below the radiator mount area . This only a problem on S1 & 2. Later cars have an air gap under a smaller radiator. Problem fixed. Oil pressure stays at 60 psi hot or cold and 20 ? 25 psi at idle.

Hope this helps

Craig

[rdssdi]

Craig

Thank you for the post. I will use it when I replace the fan.

Kindly explain where the closing plates are placed. I have a metal radiator support at the left and right side of the radiator. The nose is filled with components so placing a baffle to direct air to the radiator would be difficult at best.

Bob