Outer Limits 4x4 Board

ive done a bit of a search but couldnt really find the answer i was looking for.

Im rear mounting the radiator in my gq mwb, its running a injected holden 5L. Im just wondering on how to switch my thermos and 12v water pump. Now ive got a few ideas, Do I.......

1. run both of them off the thermo fan relay that is part of the marks adaptors kit.
2. switch both them on together from the ignition and have an overide switch to keep them on permantly incase it needs to cool down after a hard run.

would running the electric pump constanty off the igniton, even when the thermostat is closed and the engine is cold affect the engine getting up to temp. and would the pump like pushing hard with the thermostat closed.

thanks alot guys

Will having them all running off accesories mean you may have trouble restarting in some conditions? Like night stages with spotties going and what not?

And would you run the thermos through a automatic temp switch that reads the temps somewhere in the engine bay?

Running them wouldn't affect starting, plenty of power in the battery Jimmy. Running them off a temp switch would be the same as running it off the relay in the marks kit.

have your fan run off a switch and an automatic thermatic switch brazed into radiator so when it reachs a certain temp it turns on automaticly, and with your water pump run it on a seperate switch again as u may not need it all the time as its more of a precaution, as your engine water pump should handle it most of the time.

If you're still going to run the engines mechanical water pump then you won't need an electric pump. However if you're only running an electric pump then it can run all the time if you want as the engine has a bypass so water circulates around the engine block while warming up and doesn't get too hot in one particular spot. Then the thermostat will open and allow water to circulate through the radiator. So you have a couple of choices there. This is what I did.

I ran 2 x thermo fans that were run off different relays but off the same switch so if I lost one of them I would still have the other. The switch was a 2 way switch so I could have it on auto through the thermatic switch or I could switch them off completely if I was driving and bogging down in deep water and prevent the fans from hitting water and digging into my radiator. I had a warning light that turned on if I selected this setting so I'd know they were off. I also ran an electric water pump that ran off a relay that was wired into the ignition circuit so it was running when ever the key was turned on. So I could circulate coolant in my engine after a hot run without the engine actually running. This cooled down my engine and turbo while the engine was off and I could work on the car at the same time if I needed to.

That is only my way of doing it but there are a number of ways to do it. It depends on what your needs are.

Thanks toughnut, that sounds like a pretty good way of doing it. Where did you put your thermatic switch?

I planned on running both the mechanical and the 12v pumps, if the thermostat stops flow around the engine then won't the electric pump be pushing against the closed thermostat? And If the thermostat only opens when the engine is at temp then whats stopping me from running the thermos all the time. Sorry if I've got this wrong, I don't exactly how the cooling system works.

gudge wrote:I planned on running both the mechanical and the 12v pumps, if the thermostat stops flow around the engine then won't the electric pump be pushing against the closed thermostat? And If the thermostat only opens when the engine is at temp then whats stopping me from running the thermos all the time. Sorry if I've got this wrong, I don't exactly how the cooling system works.

The thermostat doesn't stop flow around the engine. It stops flow through the radiator. If you stopped flow through the engine you'd create hot spots in the engine block and that would cause problems. The thermostat doesn't stop the flow completely either. You still get some water getting past. There is nothing stopping you from running the thermos all the time but if they are too efficient then your engine may never heat up to optimal temperature. Your thermostat should open around 70 degrees which is below your engines optimal operating temperature.

I had my thermatic switch plumbed into the top radiator hose and made adjustments after running the engine pretty hard a few times until I got a happy medium.

Yeah ok, thats why I asked if the electric pump could run all the time. With the thermostat closed, the pump won't be able to push around the engine. It will be pressurising the the return hose back the engine if that makes sense, so im thinking the electric pump that pumps from the radiator back to the thermostat should only run when the thermostat is open. Im not saying I'm right, it's just the way I understand it ( which could be totally wrong).
And as for the fans, the original engine fan ran all the time and would be alot more efficient than thermos?

gudge wrote:Yeah ok, thats why I asked if the electric pump could run all the time. With the thermostat closed, the pump won't be able to push around the engine. It will be pressurising the the return hose back the engine if that makes sense, so im thinking the electric pump that pumps from the radiator back to the thermostat should only run when the thermostat is open. Im not saying I'm right, it's just the way I understand it ( which could be totally wrong).
And as for the fans, the original engine fan ran all the time and would be alot more efficient than thermos?

Was the original fan a clutch fan? If so then it wouldn't be running at full speed until the engine heated up and the clutch fully kicked in. This also allows for the fan to stop if it hits water. Not always the case though. I've seen a few of them dig into the radiator.

I see what you're saying with where you are planning on putting the electric pump. I was thinking more along the lines of the electric pump that bolts on in place of the OEM pump. In this case you'd connect it to a thermostatic switch that is set higher than your thermostat opens so it will only run when the thermostat is open. But you don't really need it. There is enough flow through the mechanical pump to cope well enough with the longer hoses to the rear of the cab and its not always a good idea to speed up the water flow too much as it will lessen the time it has in the radiator to cool down.

Hmmm alot to think about. To much flow = less time in radiator = smaller cooling effect. But on the other, hand less time in the engine aswell = less heating of the coolant. Most saying I don't need the electric pump but have see so many other comp trucks running them.

Mabey I'm just a bit biased since i already bought the electric pump haha

im running a rear mount on my lux with the 2.4 it wouldnt push the coolant around and was actually boiling before the coolant could do a round trip fitted a davis craig pump but found it to be building to much pressure when thermostat closed. i just drilled the by pass hole in the thermo stat bigger. it now works a treat just takes longer to warm up

uglystik01 wrote:im running a rear mount on my lux with the 2.4 it wouldnt push the coolant around and was actually boiling before the coolant could do a round trip fitted a davis craig pump but found it to be building to much pressure when thermostat closed. i just drilled the by pass hole in the thermo stat bigger. it now works a treat just takes longer to warm up

If you fit a thermo switch you would have the best of both worlds. Just set the switch to activate at a slightly higher temp than the thermostat.

toughnut wrote:

uglystik01 wrote:im running a rear mount on my lux with the 2.4 it wouldnt push the coolant around and was actually boiling before the coolant could do a round trip fitted a davis craig pump but found it to be building to much pressure when thermostat closed. i just drilled the by pass hole in the thermo stat bigger. it now works a treat just takes longer to warm up

If you fit a thermo switch you would have the best of both worlds. Just set the switch to activate at a slightly higher temp than the thermostat.

That's what I'm thinking.

And I guess the next questions is, where is everyone getting their thermatic switches from. A quick look on eBay, Davis craig do one for about $70

gudge wrote:And I guess the next questions is, where is everyone getting their thermatic switches from. A quick look on eBay, Davis craig do one for about $70

Thats the one that I had. I've still got a switch and pump sitting at home. Might run it on my new project. Not sure yet.

While you are answering Gudges questions Toughnut, I'll ask one haha

I've got twon thermos on the rear mounted radiator which turn on through an adjustable temp switch, and then the water pump which I use is just activated using a switch in the cab, is this set up ok, or should I change it?

Mosko111 wrote:While you are answering Gudges questions Toughnut, I'll ask one haha

I've got twon thermos on the rear mounted radiator which turn on through an adjustable temp switch, and then the water pump which I use is just activated using a switch in the cab, is this set up ok, or should I change it?

There is no way in hell that I would have TWON thermos.

That set up is fine until you forget about the switch for the pump. How do you have it plumbed into your engine? Is it a second radiator or the main radiator? If it is the main radiator, do you have it plumbed through your engines mechanical water pump? If this is the case then you'll still get flow from that and the electric pump will just act as a booster. It will also act to slow the flow of water when turned off too. As long as you keep an eye on temps you'll be fine. I rigged my set up with warning lights so I could see if something wasn't switched on. Just a fail safe for if or when the auto switching didn't work or I had them turned off manually. Just gave me peace of mind so I didn't have to concentrate on it quite so much in the heat of a comp stage.

toughnut wrote:

Mosko111 wrote:While you are answering Gudges questions Toughnut, I'll ask one haha

I've got twon thermos on the rear mounted radiator which turn on through an adjustable temp switch, and then the water pump which I use is just activated using a switch in the cab, is this set up ok, or should I change it?

There is no way in hell that I would have TWON thermos.

That set up is fine until you forget about the switch for the pump. How do you have it plumbed into your engine? Is it a second radiator or the main radiator? If it is the main radiator, do you have it plumbed through your engines mechanical water pump? If this is the case then you'll still get flow from that and the electric pump will just act as a booster. It will also act to slow the flow of water when turned off too. As long as you keep an eye on temps you'll be fine. I rigged my set up with warning lights so I could see if something wasn't switched on. Just a fail safe for if or when the auto switching didn't work or I had them turned off manually. Just gave me peace of mind so I didn't have to concentrate on it quite so much in the heat of a comp stage.

Well that's embarrasing having my I phone automatically spell "Twon"

And it's the main radiator, and still runs through the same inlet and outlet that the old radiator used, so I'm guessing it's still all the same,
I think a warning light is a great idea and will get one for sure, last year at the Lowmead 3 car comp I forgot to turn the pump on and it got pretty hot on the rally stage, whilst it's parked up at Camp Crazy's we will have to look into making the set up super reliable.
Cheers mate

If you want something to control the pump look into davies craig electric water pump controller. It controls the pump by kicking in and out like 10 secs on 20 off. then 10 on 10 off when approaching the target temp. Then once at the target temp its full on. Seems like a great idea to me.

In my rear rad set up jimmy i only use the electric water pump when it really needs it which is really rare for the driving i have done in it so far with the set up.

Gudge i just ordered a davies craig adjustable mechanical switch and the inline fitting for the probe to go in as i use to have the thermo on a switch in the cab until i decided on this set up.

I worked at repco before coming to gladdy (technically still do) so i can get them in pretty cheap for you if you want to go down that path just let me know.

Will have to work something out Mitch! Would love to know the set up for the radiator is fool proof, will have to drop by and check out your set up sometime you are back in rocky if you don't mind.

The rad set up won't be back together for a while, building all new bar work and fitting a cage at the moment.

horndog wrote:The rad set up won't be back together for a while, building all new bar work and fitting a cage at the moment.

No worries mate, when would you like me to drop my cruiser around for a cage?

And Gudge, have you found and priced the different bits and pieces you need?

Rito horndog sounds like a plan. Let me know a price for the thermatic switch and the inline Fitting. Probably pm me if you like. I've decided I will run both thermos and electric pump off the thermatic switch, and set it to come on just higher than the thermostat does. that way the pump is never pressuring against the thermostat, and they will continue to run after it has been shut down and the coolant is at a safe temp. Will probably run and overide switch inline aswell ( auto/off/manual)

And Jimmy why put a cage in when ur a full time
Navi these days. Or are u starting to get the drivers urge again.

however you set it up make sure you have some form of fail safe. i didnt just because i got lazy and ive nearly cooked the old 2.4 quite a few times (bit embarrasing waitng in line at lowmead only to turn around and see your trucks imatating a kettle) i will be seting mine up properly with the 5 litre

Not sure if I'll be doing proper events, but would give piece of mind, and could do the roof slide bars soi stop dinting the roof...

What size radiator is on the middy?