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benbenukuk

Thermostat

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Hi, If I change my 88c thermostat for a 74c one will it help to keep it cooler? cheers. Ben

In theory it could help but if your engine is running too hot, you really need to know why and remedy that!

Is the rad clean, are the fins clear allowing sufficient air-flow.

What have you checked so far ?

What are you using to determine the engine is running too hot ?

More detail will lead to more help in here and hopefully a solution that's long term...

Neil

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Mine was and is fitted with 88c stat' but with the old radiator would go over half way in hot weather. Now it sits in the middle of the gauge and nvers goes any hotter.

sounds like you might have a partially bolocked radiator, in which case a lower temp stat will likely only delay how long it takes to get too hot.

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In theory it could help but if your engine is running too hot, you really need to know why and remedy that!

Is the rad clean, are the fins clear allowing sufficient air-flow.

What have you checked so far ?

What are you using to determine the engine is running too hot ?

More detail will lead to more help in here and hopefully a solution that's long term...

Neil

The rad is clean but the are a couple of slightly damaged fins, I have had it over heat 4 time's in the last year mainly due to a dirty rad, I wanted to fit a different thermostat so that I could rest easy knowing that it wouldn't over heat sitting in traffic, when I go off-road and the rad is blocked up I can drive for 30-45mins going 30-40mph without the temp going over the half way mark then all of a suddon it will shoot up then blow the cap off the header tank which costs £45 a time, I thought that if I get a different thermostat it might help it a bit? cheers. Ben

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Hmmmm <_<

Its a yes and no type answer really

The lower the thermostat then yes the cooler the engine will run,

BUT think of a radiator in a V8 like its the engines heart

Popping in a lower thermostat (I think the lowest is a 74 or 72 one Early V8 carb)

drops the temp of the engine but if the rad is blocked it will soon overheat as the

cooling system is strangled, and V8s all have a tendancy to reach a heat point where they

are unable to recover from as the latent heat in the system and the coolant goes past the

point of no return, its a case then of stopping and letting the engine (hopefully) sort itself out,

I have even seen race V8 reach this point, when the racer stopped with all the fans on and the bonnet up

on tickover (switching it off can make the internal temps rise) you could hear the water boiling and it then

got worse eveyone stood back and the engine literally expoloded as it was unable to reduce the already out

of control heat build up

With a blocked rad your on this same slippery slope, you need to have the engine temp under control by some means

and increase cooling options, this could be fans, cowlings on the rad if you don't have one and holes / vents IN THE RIGHT

places, and if need a bigger higher flow bigger size / cored radiator or as in my case all of the above, the lower

thermostat gains only a small amount, and if the temp prob is big, prob nowhere near enough to sort it. Also check your

antifreeze has the highest mix recomended as this will help drop temps, but don't go mad, you can similarly buy water wetter

which helps too

Lastly to keep a V8 cool fans need to come on early and hard so that the heat is kept UNDER control and not "Ooo its too hot"

shove the fans on - thats too late and takes more time / fans / effort to then get it back under control

Nige

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Hmmmm <_<

Its a yes and no type answer really

The lower the thermostat then yes the cooler the engine will run,

BUT think of a radiator in a V8 like its the engines heart

Popping in a lower thermostat (I think the lowest is a 74 or 72 one Early V8 carb)

drops the temp of the engine but if the rad is blocked it will soon overheat as the

cooling system is strangled, and V8s all have a tendancy to reach a heat point where they

are unable to recover from as the latent heat in the system and the coolant goes past the

point of no return, its a case then of stopping and letting the engine (hopefully) sort itself out,

I have even seen race V8 reach this point, when the racer stopped with all the fans on and the bonnet up

on tickover (switching it off can make the internal temps rise) you could hear the water boiling and it then

got worse eveyone stood back and the engine literally expoloded as it was unable to reduce the already out

of control heat build up

With a blocked rad your on this same slippery slope, you need to have the engine temp under control by some means

and increase cooling options, this could be fans, cowlings on the rad if you don't have one and holes / vents IN THE RIGHT

places, and if need a bigger higher flow bigger size / cored radiator or as in my case all of the above, the lower

thermostat gains only a small amount, and if the temp prob is big, prob nowhere near enough to sort it. Also check your

antifreeze has the highest mix recomended as this will help drop temps, but don't go mad, you can similarly buy water wetter

which helps too

Lastly to keep a V8 cool fans need to come on early and hard so that the heat is kept UNDER control and not "Ooo its too hot"

shove the fans on - thats too late and takes more time / fans / effort to then get it back under control

Nige

At the moment it has the std fan with no cowling, I did get a cowling but it didn't seem to fit so I didn't bother getting another one, Do you think it would benifit from putting twin electric fans on the otherside of the rad and leaving them on all the time? Ben

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At the moment it has the std fan with no cowling, I did get a cowling but it didn't seem to fit so I didn't bother getting another one, Do you think it would benifit from putting twin electric fans on the otherside of the rad and leaving them on all the time? Ben

With no cowling it's no wonder the fan's not having the desired effect. The subject of electric fans has been covered many a time, search for "Kenlowe" or just "electric fan" or even "x-fan" for much information on finding, fitting, wiring, etc.

A 74 deg stat will make the engine run at 74 deg while the radiator can cope, as soon as you are in a situation where it would normally overheat, it will still overheat, it'll just be starting from 74 deg rather than 88 so may take a few seconds longer to boil up. You need to sort the problem of insufficient cooling, not running temperature.

The cheapest & easiest option is to stick a cowling on and see if that cures it. If not, you need to give the rad a really good clean so you can see daylight through it all the way over - they pack with mud which then dries hard & is a b*gger to wash out, sometimes the best way is to put it in a bath of water for a day or more to let it all soak in & allow it to be washed out. That's assuming your rad is in good nick to start with.

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^^^

Wot he says :)

Fitting the cowling will prob knock 10-15 degrees off the top end.

DO IT - and hold changing the thermostat until done

You'll be amazed

Nige

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If its an old rad it may be well silted up internally. Any cold/cool spots on the rad? Flushing MAY get some of it out.

Replaced mine recently & the weight difference was startling.

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If its an old rad it may be well silted up internally. Any cold/cool spots on the rad? Flushing MAY get some of it out.

Replaced mine recently & the weight difference was startling.

As far as I can tell there isn't any cold/cool spots on the rad but I am going to take it out and give it a good clean inside and out, cheers. Ben

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As far as I can tell there isn't any cold/cool spots on the rad but I am going to take it out and give it a good clean inside and out, cheers. Ben

If you can leave it out for a while then filling it with something like Holts Radflush and leaving it to stew for a bit would help. If you could rig something to pump the brew around for a few hours would be even better.

No doubt others will be along to offer some other product or herbal remedy. This is fine as all I'm suggesting is that something to help break up the sludge is better than just a 10 minute fresh water backflush.

Steve

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