hi there guys,

i still seem to have a problem with my pinto rush overheating, well more like its running very very hot, i would expect it to normally run around 90 degrees but on a trip out last night it was running at 104!

i have flushed the system twice, checked the thermastat, airlocks etc but stitt have this problem,

primarily i think that my rad is just not up to the job, the core measures 300mm across and 350 high, total width is 360mm and its 60mm deep,



the other thing that i think may be happening is that the pressure cap isn't sealing properly, so i have ordered a new one to make sure.

the only other thing i can think of is that there is not enough air getting through the rad, as it enters through the nose cone it can escape through the open sides of the suspension, downward threw the floor & around the side of the rad (paths of least resistance etc)

can anyof you recommend anything or even post up some pictures of your cooling set up, im on the verge of shelling out for a custom dax rush specific alloy rad from radtec but they are £275!

all opinions welcome!

That's an unusual place to put a rad, I must say.

If you look at a naked MK, MNR or book Locost you'll see that the rad is right up front, well into the nose cone (roughly where your oil cooler is sitting at the moment). This makes sealing the gaps around the edge very easy.

Yours isn't a very big rad either...

[Edited on 3/6/09 by David Jenkins]

i'd always start with the pressure cap. its the easiest cheapest thing to start with.

that radiator does look pretty small though. mine's twice the size of that! lol it might be big enough though

is there any way you can mount the radiator right up front? make the most of the air? or make some kind of ducting to point more air at it?

or can you swap the oil cooler and rad around? do you REALLY need the oil cooler? i'm not saying lose it, but if it can move to make way for the rad...

[Edited on 3/6/09 by blakep82]

what do your plugs look like - running lean creates a lot of heat ( learnt that leson from my v8 ) ?

does the fan cool the temps when it comes on ?

regards

agriv8

If you think its air flow have tried hard wiring the fan so its on all the time, if it behaves then you have a couple of choices, duct air into the rad or get a proper rad,just out of interest is your fan a blower? Can it be changed to a sucker, the fan itself is covering alot of the surface area of the rad, if you could get a sucker and put it the other side I'm sure things would improve. Is there enough space to even put the viscous fan back on the pulley?

Cheers

Rich

[Edited on 3/6/09 by RichardK]

Have a search for surrey dave and polo rad, you will find dimensions of the one most people use...

I guess you have checked the timing..

Dan

when it was running at 104 the fan was on constantly!

i've just seen this on ebay, pity the outlet is on the side

renault 5 turbo rad

yes have checked timing, car only runs lean under acceleration, which obviously needs sorting with more data logging!

fan is a blower, if i wired it the other way round would it become a sucker?

[Edited on 3/6/09 by omega0684]

As others have said, very small rad in an unusual place and pretty much blocked of any good airflow with the fan on the front and really close to the engine at the back too.

Rad really ought to be right at the front (which is where I am sure yours started off?!) to get the best airflow possible. Even then cooling can be marginal...

David

PS here's a pic of mine, with the nose fitted there is less than 1" gap all the way around







[Edited on 3/6/09 by flak monkey]

Here's my Polo rad on my book chassis - when the nose is fitted the rad is only 5 or 6 inches from the hole in the front.


naked car

BTW: the bowl was there to catch water when I drained my system before removing the inlet manifold - not to catch oil drips from the crossflow - I've got a much bigger receptacle for that!

~~Hi

There are loads of dax rushes running this radiator and in this position,

Most MC cars run this configeration so i would look else where as these rads are normally quite effiicient for there size,

they are fitted to there turbo engine cars also and had no probs so prob look for air locks and pressure cap,

alos anti freeze/summer coolant consistancy,

good luck,

ps guage is reading write i persume??

can someone post up the dimensions of the polo rad please

Just looked at some of your pictures, what are you using for a grill?

Andy

quote:

---

Originally posted by Andy W
Just looked at some of your pictures, what are you using for a grill?

Andy

---

A simple ducting test would be to buy some hardboard and hot glue / gaffer tape it in place around the rad. Won't cost much and will be easy to remove once you know if it makes a difference.

Are you sure you don't have any air locks?

If you want to pop over to nuneaton on Sunday I can wizz the infra red thermometer on it and we can see if there are hot / cool patches (if you're worried it won't make the journey i should be in cov in the evening or you could just borrow it for a couple of weeks).

i take it this is the polo rad that most people use

eba y link

its the 430x380x24mm one

Alex,
Yes, that looks like it. Got mine from adrad £38 delivered, next day. Their site (here) shows 448mm between the mounting pegs at the bottom.
I'll measure my rad tomorrow...
Looks like you need to build a duct to contain the air between grille and radiator.
Although mine is close to the grille (about an inch at the bottom and 3 inches at the top, today I started fitting baffles to impede air spilling around the sides and top of the rad. It's a bit of a jury rig but I just want to see what benefits, if any, arise from doing this. For the offside I cut some Al sheet and fixed it with tie wraps and gaffer tape; near side is a piece of thin plywood secured to the unused mounting bosses on the front side of the rad tank. Haven't done the top yet - having to scratch around for suitable material! But, as I say, I want to see how effective these baffles are and then will remake them properly if needed.
Have you connected the small stub on the 'stat housing - I'm being persuaded that it is necessary, although mine has been blocked off ever since its days in the donor.
I also tried propping the trailing edge of the bonnet open by 1/2 inch and that seemed to help in letting hot air escape; so I may well bite the bullet and cut holes to vent it better. My bonnet is quite tightly sealed to the scuttle with a strip of adhesive foam rubber.
Cheers,
John.

I've got a couple of rad's very similar to that Polo one spare if you want to try one for fit ?
Also got a bin bag full of assorted hose bends to work out connecting it ?

................. the thing is, if there are loads of dax rushes running the DAX radiator in the dax position, then the problem lies alsewhere!

Rad looks fine to me even if it looks like some ducting would help but nobody has asked the very obvious questions.

(1) Is a bypass hose fitted ?
(2) What temperature of thermostat is fitted ?.
(3) Has the ignition timing been checked ? --- retarded causes rapid over heating as soon as the revs increase beyond 1500 or so.

Have you checked if the gauge andor sender unit is accurate.

the fact that the radiator is fine in other pintoed daxes is a bit worrying but here are my thoughts:

1. how are you measuring the temperature? if you have faulty sender/gauge or mismatch of parts then
you cannot rely on that. if the water is boiling and you are losing water then check pressure cap is correct or you have a genuine problem.

2. fan - I am not a fan of these clip through the rad types. also there is a lot of plastic in front of it that is not doing air flow any favours as well as the rubber tabs clip things which again are blocking off the radiator.

fit a larger fan that covers more of the radiator with an open front using brackets.

3. check fan is spinning in correct direction.

4. ducting - you want to ensure as much as possible of the air entering the nose cone is going through the radiator then using thick carboard, knock up a box (including floor and top) from nose cone opening to the radiator, floor behind radiator must be open to allow air to get out.

5. oil cooler so far away from the radiator is interrupting the air flow big time; you may want to make box for the
front and rear; also route the cooler lines out of the air flow - not so easy as you don't have much slack (you could try running without the oil cooler).

6. check the water pump is running correctly - tuning right way? impeller turning and not damaged?

7. remove thermostat? check for air locks?

8. check timing and fuelling

what happens when idling? engine should warm up, fan kick in, maybe run for 5 mins then switch off then repeat. if fan never comes off, then there is a problem.

If your temperature sensor is on the engine as mine is, is the radiator actually hot as well, if so you dont have air locks etc?
Is the fan going the right way, if its blowing air forwards that won't help!
I would definately cowl in the radiator.
Make sure you dont have ducts open to the bay behind the rad, as this can let air in and equalize the pressure across the radiator (air flows when you're moving and the fan is off due to higher pressure in front of the rad compared to the back).

Best of luck
Hugh

Alex,
Polo rad dimensions (in mm) are:

Width:
- core 378
- overall 480
and you need about an extra 20 mm at n/side top to connect to the bleed port

Height:
- overall 325 plus 15mm mounting pegs at bottom

Thickness:
- core 34
- tank 50

Everything connects on the nearside;
- main in & out stubs point rearwards (both take 32mm ID hose)
- Thermoswitch port about halfway down
- bleed port at top.
HTH
John.

Hi There

I'm running pretty much the same setup as you on a Rush and mine runs at around 90.

The only differances i can see are the rad mountings mine sits right at the front of the chassis.

Might sound stupid but i would also check that the fan is frunctioning correctly as you can wire then up to suck / blow, when i checked mine first off it was working the opposite way than it ahould have been.