Thread: Help - V8 overheating on the sand!

I have just gone through the same exercise, my County was getting rather warm while sand driving. I had the radiator cleaned and 10% of the core had to be blocked off due to its poor condition.It still wasn't satisfactory so I bought a complete new radiator from Rovacraft and put Davies Craig thermo switch on my electric fans and the problem is solved. Rovacraft normally sell the new radiators for @ $350.00, a lot cheaper than the $480.00 I was quoted for just a core.

Regards
Maggsie

It sounds like you may also have an issue with the fans or the fan circuit.

First place a multimeter on the power side of the fan switch . You should have 12V. If you have 12v , then bridge the switch. If the fans do not work you need new fans or the earth from the fans is crook. If the fans work by bridging the switch the switch is crook.

If no 12v then work back through the relay and fuse to find the open circuit.
Without looking at the circuit, there must be 2 power feeds, one through the thermo switch for overheat and one through the aircon switch. Try the overheat circuit first as it will tell you whether its fans or power.
OK I looked at the circuit. there are two separate relays, the aircon/heating relay, and a specific relay for the fans. the fans share earth with the compressor clutch, so if the clutch works then the fans earth should be OK , but check anyway.
To check the fans you can also just hot wire them from the battery with a length of wire.
Regard s Philip A

Get yourself some of those Staun deflators. They work a treat and preset them at 11 - 12 psi. and watch your 4wd laugh at that soft sand. It probably is a good idea to get your core rodded out i have had a few cars with this prob and all overheat past 100 kmh too. But do try 12 psi on the sand. I have found it makes a lot of difference to the 15 - 16 psi that my friends told me they used and a lot less hard work on the engine too

Originally Posted by PhilipA

It sounds like you may also have an issue with the fans or the fan circuit.

First place a multimeter on the power side of the fan switch . You should have 12V. If you have 12v , then bridge the switch. If the fans do not work you need new fans or the earth from the fans is crook. If the fans work by bridging the switch the switch is crook.

If no 12v then work back through the relay and fuse to find the open circuit.
Without looking at the circuit, there must be 2 power feeds, one through the thermo switch for overheat and one through the aircon switch. Try the overheat circuit first as it will tell you whether its fans or power.
OK I looked at the circuit. there are two separate relays, the aircon/heating relay, and a specific relay for the fans. the fans share earth with the compressor clutch, so if the clutch works then the fans earth should be OK , but check anyway.
To check the fans you can also just hot wire them from the battery with a length of wire.
Regard s Philip A

Thanks Philip - I'll check the overheat circuit 1st as I know the aircon is crook. Think I'll get on and order a Rave CD for this as the Haynes manual isn't so clever with wiring diagrams.

I did try a hot wire from the battery (+ve and -ve wires) and neither fan worked, so it looks like several issues which is why I've been pulling my hair out. It's nice to know that I'm on the right track though.

Originally Posted by maggsie

I have just gone through the same exercise, my County was getting rather warm while sand driving. I had the radiator cleaned and 10% of the core had to be blocked off due to its poor condition.It still wasn't satisfactory so I bought a complete new radiator from Rovacraft and put Davies Craig thermo switch on my electric fans and the problem is solved. Rovacraft normally sell the new radiators for @ $350.00, a lot cheaper than the $480.00 I was quoted for just a core.

Regards
Maggsie

Thanks Maggsie, this sounds like the best option - cheap and you can't beat a new item. I'll give Rovacraft a bell.

Originally Posted by stevejo43

Get yourself some of those Staun deflators. They work a treat and preset them at 11 - 12 psi. and watch your 4wd laugh at that soft sand. It probably is a good idea to get your core rodded out i have had a few cars with this prob and all overheat past 100 kmh too. But do try 12 psi on the sand. I have found it makes a lot of difference to the 15 - 16 psi that my friends told me they used and a lot less hard work on the engine too

Will give this a try, but was always worried that I'd break the bead at such low pressures without locks fitted. Will take you at your word and hunt you down if I blow it

Please be cautious if you do drop your tyre pressures as low as 12 psi. There are issues associated with lowered tyre pressures other than bead breakage. If you lower your pressures you must restrict your top speed possibly to as low as 40kmh max as under inflated tyres generate shed loads of heat and can break down/self destruct with catastrophic results. Land Rover recommend a minimum of 16psi and also recommend restricted top speed. Don't trade off safety for flotation

I'm with Foz.
I usually run about 18-20 on the beach and dry sand tracks and have never had an issue (and I am a strong advocate of low pressures as soon as leaving the tar), 16 would be ok, but Í've never found anything in Qld that needed it. The dry dunes of places like Stockton may be very different though.
I've been to 8 in Suzukis but they are a far far lighter car.