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allye

Choosing A Big Radiator, Over Cooling?

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allye

Hi all,

 

After some advice about big radiators. It will be trying to cool a 260bhp V6.

 

At current the standard 406 radiator barely keep the standard D8 V6 cool in the 309. I had the same issue with both GTI6 engined 205's, temperatures rising in traffic. I actually had to pull over on the way back from pugfest this year in some traffic <_< So basically I'm done with worrying about the engine over heating and want to do it properly this time.

 

The standard 406 radiator doesn't have a hope in hell in cooling the new engine setup so I'm looking down other routes. The 406 system only has the in and out points on the rad with no over flow so my options are fairly wide open. (was thinking about a custom job, just thinking about different routes at the moment)

 

So my main question is can there be a issue with over cooling? I'm looking at 50/60mm core big radiators from evo's, FTO's etc which have the outlets in kind of the correct location.

 

Thanks, Ali

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Tom Fenton

As long as you have a thermostat you cannot over cool the engine as the stat would close.

 

However you will find the most gains are to be had by sealing the rad to the front of the car, this means all airflow has to go through the rad, rather than being able to go around it. This makes a big difference when the car is moving.

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allye

Good tip about sealing the front end. Some simple sheet metal to direct airflow. Been looking through ebay and the like and a lot of different radiators, so far early Evo radiator are looking very good with bout outlets on the left side like a 406 and the outlets are only 1mm different in size, and there are many performance items available.

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Anthony

Surely if it's only getting too hot in traffic then it's an issue with airflow (ie the fan/s aren't pushing sufficient air through the radiator) rather than the radiator itself having insufficient cooling capability?

 

Normally insufficient cooling from the radiator would show up under sustained load, particularly at lower speeds

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allye

Couple times the temp has risen quite high under load up hills etc, the 406 radiator will never be up to the job of cooling the new V6 any way.

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welshpug

George uses a Golf VR6 rad, its pretty close in dimensions to the 406 rad, just a little narrower.

 

These do run quite warm but the fans keep on top of it, even in the alps.

 

IIRC he has two 12" fans running off a standard thermoswitch, it has no thermostat we found, as the temp dropped right off when running down the very long descents, I think one was about 8-9 miles at least rolling down hill in gear at 60 without throttle!

 

 

Main issue is getting something that fits and has a decent capacity, I think you would be better off getting a rad from someone like http://www.allisport.com if you really do need the extra capacity.

 

 

 

 

As an aside, have you made sure it has the 205 temp sender and warning light switch? we removed both the blue and brown V6 senders and fitted the two single spade 205 units.

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allye

Yer I know George has the VW rad, there are a few higher capacity ones about too. Fitting the correct sender will be something I will look into when the loom is made. Getting something to fit shouldn't be too much of a issue seeing as the large (as in width) 406 item fits the 309 happily, there a fair few slightly narrower 45mm, or even 50mm core radiators which is what I really would like to do with 1x 12' fan and a oil cooler.

 

I'm hesistant (however prepared) to spend, what, £300+ on a radiator when you can pick up a decent sized one for around £150.

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camgti

I'm amazed at the amount of cars on this forum that have problems with overheating. I've never had any problems with many different 205s and I live in Australia where the temps are way higher more often than the uk. 35 degrees plus, hot Tarmac (melting) in traffic etc.

 

As Tom said, its good to get a good seal on the rad. force all the air through it. You'll also want make sure there is enough room behind the rad to enable to air to flow through itmaybe run a cooler 83deg thermostat and make sure the rad is actually in good condition and not either blocked and has no muckmetc between the fins.

 

So answering the question about trying to cool a v6. We have many v6 cars here, many v8. Lots of them running 600hp plus. To cool 260 hp, I would say a thicker, triple core rad thats well sealed to the front air passages. Running 2 fans on a cooler thermostat switch. Making sure the system has zero leaks and the water pump is fresh with no damage should do the trick.

 

Is the much room behind the rad for air to flow through? Must be real tight in there with a V6!! Epic car by the way. Very jealous.

 

Cam

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TooMany2cvs

Couple times the temp has risen quite high under load up hills etc, the 406 radiator will never be up to the job of cooling the new V6 any way.

That's still suggesting airflow - you've got a lot of heat going in, but relatively little air flowing over the rad. Are the fans kicking in?

 

I'm amazed at the amount of cars on this forum that have problems with overheating. I've never had any problems with many different 205s and I live in Australia where the temps are way higher more often than the uk. 35 degrees plus, hot Tarmac (melting) in traffic etc.

Probably because you guys NEED the cooling system to be right. Over here, you only need fans in fairly unusual circumstances, so they're often missing when most needed, and people blame everything else...

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allanallen

Why's your new engine going to run hotter? It may well run cooler!

Bare in mind there's plenty of us on here running well over double the original engines output on standard 205 rads.

What's the rest of your system like? Nice pipe runs with no restrictions?

What temp thermostat is fitted and is it working correctly, how many fans do you have and are they working as they should? Pullers or pushers?

A v6 in traffic on tickover shouldn't take a massive amount of cooling so your problem may well lie elsewhere??

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allye

I'm not massively interested in solving my current problem of it running too hot as it will be a entire new engine, radiator and the hoses that go from the stat to the rad will be changed. At current they seem to have too many bends in for no reason. Also I'm pretty sure I know wny its been over heating........ (it has no cowling around the fan)

 

jeram309v6_35_zps0aa496c9.jpg

 

I've just never done anything about it. With the new motor I will find the lowest stat I can and the fan will be controlled by the ECU. Just 1x 12inch pusher fan for 2 reasons. Firstly I would like to fit the oil cooler on the other side of the radiator and also it would to too close to the front exhaust manifold.

 

Allan, I blindly assumed a more powerful engine sat in the same area would run hotter, seeing as its basically the same engine just producing more power?

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allye

I've just been looking through all sorts of radiators from various different marks, just need the outlet/inlet in sort of the correct location and a 50mm core, so far this one is winning being similar dimensions to the 406 rad but 50% thicker.

 

http://www.ebay.co.uk/itm/151088278693?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

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Goliath

Sorry only just seen this thread, I am not surprised it overheats with that fan on it. You really need a cowling on the fan, it will be much less effective without it.

 

I am running a VR6 rad with twin fans 10 or 12", I have no clearance behind the rad for hot air to escape yet I don't have issues with overheating. Hooning up an alpine pass in 30+ degree heat the engine got hot, the needle went up as expected but the red light didn't come on.

 

Also it got hot on a hard lap of the nurburgring but again the red light didn't come on.

 

It will sit in traffic all day without overheating.

 

 

I think if you are going to get a new rad then getting a custom one might be best, you can get it made to your exact specs for peace of mind and have the inlet/outlet in the ideal places. It all depends if you can shop around and get it done for a decent price.

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rallyeash

That fan ain't guna do s*it!

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TooMany2cvs

Also I'm pretty sure I know wny its been over heating........ (it has no cowling around the fan)

 

jeram309v6_35_zps0aa496c9.jpg

Just for a laugh, is there any chance of you firing the fan up, then putting some kind of smoke source just in front of it, and posting some pics? I'd love to see exactly how little air is making it through the core...

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rallyeash

stick a decent make fan on or a pair of and get the cooling system streamlined.

 

that'll keep it cool

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GilesW

Without a cowling I'd expect at least 50% of the air flow just to be thrown to the sides.

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allye

Yep, brilliant, thanks for all the pointers on how pointless that fan is in which I had previosuly pointed out!

 

I also said not interested in a solution to set up (as previosuly pointed out) I'm after advice on radiators, in which the 406 one will not be staying.

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GilesW

Oooo handbags.....

 

(I was responding to TooMany2cvs post).

 

 

I think what most people are trying to tell you is that any reasonably sized rad would work if you whole cooling system (including the fan) is put together properly.

 

If it's a track car which you'll be driving on the limit for 30mins at a time (or more) then maybe a little deeper thought maybe given to it. But your's is mainly road isn't it?

 

And despite having a thermostat - yes IMO you can go 'too big' on your water system and it take forever for the water volume to heat up to provide a stable optimum running temperature, as well as weight (although you have a V6 so doubt that's a real concern).

 

Oil temprature is critical too - you want that and you water to get to it's optimum as quickly as practically possible and stay there. Many people over cool oil just to earn some pub points with spec.

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Anthony

I'm confused - the radiator is not the immediate problem, so why are you hell bent on changing it?

 

After all, the 406 radiator was deemed perfectly sufficient by Peugeot for cooling the engine when it was in the 406 shell, in considerably hotter climate than we have here in the UK and with things like the AC condensor etc too, so why would it not be up to the job of cooling the same engine in a 309 if installed properly?

 

I said in my earlier post that the symptoms you mentioned sounded like a fan airflow issue rather than a radiator one, and having seen how the fan setup has been done, it's pretty clear that is correct. Sort the radiator fan setup and I'm willing to bet that your cooling woes will disappear in an instant.

 

George has shown that a radiator similar to what you've got was more than capable when we were in the Alps during the summer, in demanding conditions where even a humble 8v was getting distinctly warm - prolonged high revs, high load, comparitively low speed (and thus limited airflow over the radiator) mountain climbs in 30 degree temperature. If it'll survive that, I'm pretty confident that it'll survive anything you can throw at it day to day here in Blighty.

 

I don't see the cooling requirements for your new engine being dramatically different to the current one tbh.

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allye

This is all very very well and good, but at the end of the day I don't want to lunch a engine that costs more than most GTI's........ For the sake of a couple hundred £ I'll be finding a big radiator to fit.

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welshpug

I can't see you getting any larger unit in there, given its wedged in between the chassis legs, and bonnet and front crossmember already...

Edited by welshpug

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wicked

After all, the 406 radiator was deemed perfectly sufficient by Peugeot for cooling the engine when it was in the 406 shell, in considerably hotter climate than we have here in the UK and with things like the AC condensor etc too, so why would it not be up to the job of cooling the same engine in a 309 if installed properly?

 

 

I know people who did fit a 309 bumper on 205 and got cooling problems with it... So maybe it's not the radiator/engine but the car.

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Goliath

What radiator do the clio V6's run? Might be a possibility?

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