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I've got a 110 3.5 carb V8 on petrol / LPG.

The previous owner has fitted 2 kenlowe electric fans, complete with adjustable thermostat and interior on/off switch. The way it is wired, the internal switch turns the fans on regardless of temp, and if the switch is off and the engine gets hot, the adjustable thermostat kicks in and the fans spin as well.

Just a quick query after I spent the afternoon furtling around looking (and finding), my dodgy dry connection, causing one fan not to spin intermittently.

Is there an advantage to having an adjustable thermostat? I know it's nice to be able to turn the fans off when wading, but is there any advantage to running the engine warmer? Or would it be better (as my basic physics understanding) to keep the fans on, and run the engine at a much cooler temp?

Cheers guys!

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Running warmer is better for emissions I believe. Really for your fans you want them to come in before it overheats, but not so soon that it's cycling on & off every time the thermostat opens. Standard stat being 88deg I think, so that's teh "normal" operating point for the engine.

I'd got for a 3-way switch (on-off-on) so you can use it to force the fans on or off, or leave the stat to do its thing. Just remember to turn the fans back on after wading :unsure:

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Running warmer is better for emissions I believe. Really for your fans you want them to come in before it overheats, but not so soon that it's cycling on & off every time the thermostat opens. Standard stat being 88deg I think, so that's teh "normal" operating point for the engine.

I'd got for a 3-way switch (on-off-on) so you can use it to force the fans on or off, or leave the stat to do its thing. Just remember to turn the fans back on after wading :unsure:

With the right switch and wiring you can set it up to turn on a small 12v buzzer to sound when you turn the fans off for wading, this way you won't forget to turn the fans back on :i-m_so_happy: I have done this for mine.

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Running it hotter will also give you more cooling capacity as the thermal difference between the air and the water will transfer more heat for the same given amount of time as the water passes through the radiator.

This is true as long as your radiator is up to it, if it's marginal you want to catch it quick before it starts to ramp up - but if it's marginal you really want a new rad anyway!

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This is true as long as your radiator is up to it, if it's marginal you want to catch it quick before it starts to ramp up - but if it's marginal you really want a new rad anyway!

The radiator is in good nick, and the fans are doing a pretty good job, you can see the temperature needle moving down within about 10 seconds or so of turning on the fans, certainly don't think I need to invest in an increased cooling capacity just as yet. Save my pennies for other toys, such as door bottoms that aren't holes held together with rust.

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  • 8 months later...

Hi guys,

related to this, I'm pretty sure my thermostat (the one in the engine, not the fan controlled one) is now dodgy, I'm going to whiz it out and test it, but due to relative inexpense, I will have a new one ready to pop in if it fails - so here is the question.

Should a 110 (pre-defender) 3.5 V8 have the 82oC thermostat (602687), or the 88oC thermostat (etc4765), and will it make much of a difference? Are fitments the same? just temperature different?

Many Thanks,

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Early carbs were 74C IIRC, later 82 (which I run in my 4.0 P38 unit) and EFI onwards it was 88.

The P38/Disco later V8s I think ran 92C stats, but they are a stupid plastic design rather than a nice metal discy thing :)

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  • 4 weeks later...

Well, my thermostat was not too bad, but fitted a nice new shiny one anyway, and the gasket. However, my problem persists.

I've not got much time to play with it for the next few days, so was wondering if I could build a plan of attack prior to getting the spanners out.

The v8 appears to be overheating. The fans work (as in turn round rapidly, as fans should), the radiator I thought had a decent level of coolant in it, and I;ve topped up the expansion tank. However, within about 5-10 mins of driving, the needle heads towards the red, and struggles to come down again unless I reduce to idle, then it does come down.

BUT. I am faced with a small puddle of bubbling coolant and steam coming from the top of the manifold, just anterior and inferior to the thermostat housing. There appears to be a good seal around the thermostat housing itself, and I can't obviously locate any holes or cracks in the hoses around this point. Any ideas about tracking down the leak, or is it just worth changing the hoses and see what happens? I've done the usual and tightened all the clips, and still no improvement. The top hose going from the radiator also doesn't pressurise when the engine is running, I'm assuming this means that there IS a sizeable leak somewhere, and needs finding.

Also, just to put my mind at rest, what would be the symptoms of a water pump failure?

Thanks,

Mike

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