Radiator

[p.mole1]

Can anyone recommend a radiator? my car is a 1995 with a copper radiator. Since fitting a 1.8 it has been getting a little hot 90 degrees + on track days. It has an 82 degree stat and normally runs at just over 80 degrees so I think it may be a bit small. My oil has been getting up to 110 degrees + is this too hot.I would rather not fit an oil cooler, more weight and complexity. I'm hoping a larger radiator will do the job.

[Alastair B]

Radtec Aluminium and there is a club discount I think, check out the discounts page first

http://radtec.co.uk/products/227/Caterham-7.htm

 

 

[7 wonders of the world]

Speak to the guys at Alicool

[p.mole1]

Thanks I will try a bigger radiator and see if that keeps the oil cooler

[rj]

How would a bigger water radiator keep the oil cooler?

 

[Shaun_E]

For track work, you'll probably need an oil cooler of some sort to keep the oil temp down. A Mocal Laminova is a good idea along with a better radiator as the Laminova will effectively dump more heat into the cooling system. 110 deg oil isn't a major worry but you probably wouldn't want those temps for a long period. I had the same issue years ago when I had a K series so fitted a Laminova. When I moved to a dry sump K the issue went away but now with my Duratec I'm back using a Laminova. It has the additional benefit of a faster oil warm-up.

[Stridey]

My car, a 95 Crossflow has an oil cooler in front of rad. 

As it seemed to run hot I fitted a larger fan. My theory being the oil rad was blocking flow a little so a larger fan would cover a larger area.

This worked well. However, after a shunt the rads were both replaced and now holds temp perfectly even in standing traffic.

So, my advice would be try a fan first, knowing that when and if you replace rad and fit an oil cooler the money on the fan won’t be wasted as you’ll transfer it across.

[p.mole1]

Unfortunately I cannot fit a Laminova because I have a remote thermostat in the top hose. I'm assuming a larger radiator will help? I had to remove the grill at Croft as the water temperature reached 100 degrees and I'm paranoid about the engine turning into plastercine. Since I am running a wet sump I'm sure the oil level is probably too high if you follow Caterhams method but that is preferable to oil surge.

[Roadsport06]

A standard rad should be up to the job with your power.

Is your coolant temperature confirmed - it could be your temp sender not reading accurately.

Is your thermostat opening fully/at the right temperature?

Do you have an air lock?

I'd rule those out before changing the rad.

I needed to change my rad as it was leaking and went for a radtec. Fairly local to me. Does the job and had a bigger fan as they hadn't got one for mounting the smaller fan in stock.

[Drumster]

When I fitted the Zetec I used the Ford aluminium rad (as sold by Caterham) and the 9" fan combo from the x/flow. This worked well while the Zetec ran on Carbs, but when I fitted the TBs I couldn't keep the water temp down. Solution: Radtec Extreme 7 Rad and 11" fan. Temp rarely rises above 95 deg whatever the circumstances. I also run a 10 row oil cooler in front of the rad.

[rj]

Not even i 32degrees and constant hooning I have a problem with a +200BHP K-series with standard radiator on trackdays. The water temp is steady at 75 degrees. Are you sure everything else is OK?

[p.mole1]

My standard radiator seems rather thin, I do not have any air locks. I think I'm going to fit a better radiator and an oil cooler.

I have just dropped of a VVC head at DVA so I want to make sure when I put it all back together there won't be any issues. I don't think there are any sensor issues as the temperature is rock steady on the road, both oil and water never deviate from 80/85 degrees. I don't think the thermostat is an issue and I always bleed the radiator by removing the the bolt on the top of the rad.  

[SLR No.77]

If your car is predominately road use and track days, i.e. not a race car, do not fit an oil cooler because you'll do more harm than good running the oil too cold. Look harder at what you already have ...

Why do you need the remote thermostat? 

Where are your temperature senders located in the cooling system?

For a non-race Caterham the well-established way of controlling oil temperature is by using a Laminova. Also the use of a remote stat is a questionable benefit, better to go the PRRT route or leave it standard and get everything else right. Only then you can decide if a bigger rad is really needed.

Stu.

[p.mole1]

Hi Stu,

when I was running the thermostat in it's original position the temperature used to cycle up and down, I tried various different stats, all to no avail. I also drilled a small hole in the thermostat but the engine took longer to heat up. I have also read Des Hammill's book of doom in which he states the that the position of the standard thermostat promotes thermal shock

My Oil sensor is in the thermostat housing and water sensor is in the water rail above the exhaust, ( I doubt this is a problem due to the volume of water passing though this) I assume the original gauge is not very accurate, it just gives you an indication but it's not good when its getting towards end of the scale!

I would not be concerned about oil temperatures at 110 and water getting to 100 on any other engine but I don't want cause issues with excessive heat, hopefully with my new VVC head I should be making 175 Bhp + that's going to be even more heat dumped into the oil and water! If I fit an oil cooler it will be in conjunction with a thermostat.

 

[SLR No.77]

For information ... with the standard thermostat setup if the temperature cycles up and down it's most likely to be an airlock in the system around the stat .... this can be avoided and usually involves filling the system with coolant slowly and from the rear of the engine. Without the airlock there'll be no cycling and the bypass hose takes care of reducing any thermal shock.

Also the gauge sensor above the exhaust is prone to false readings, particularly in slow traffic the heat from no.4 primary can have a big effect on the temperature you're seeing on the gauge. If you do a search on Caterham's parts site you should be able to find a small pipe that enables both the gauge and ecu coolant sensors to be positioned in the by-pass hose further away from the primaries, this will give a more stable and accurate gauge reading.

[SLR No.77]

What do you mean by oil sensor in the thermostat housing? Your remote one or the original?

[Paul Mason]

Phil, I'm K and remote QED, 82 degree stat, though dry dumped and the car is fitted with a Radtec radiator. Temperature cycles 80 to 85 as thermostat opens and closes when moving. On a cooler day, sticks more around 82. In traffic will rise, but ECU fan switch kicks in at 94 and I've also got an override switch. Oil (comma motorsport 5w50) usually runs at 75-80, will get a bit warmer in traffic. Only done 1 track day and 1 handling day, water temp was up though fan took care of it and oil up at c. 100 to 105 after thrashing.

[Paul Mason]

Set-up

[p.mole1]

Hi Stu my oil sensor is in the filter housing mounted on the side of the block, I don't have a dry sump which probably explains higher oil temperatures around 110 after 5 laps of Croft and still rising.

Hi Paul your radiator is at least twice as thick as mine! same thermostat housing,my water temperature was nice and stable ( if a little hot for a 82 degree stat ) once I removed the grill but shoots up as soon as I leave the track.

I had my new head hardness tested by Dave, it is not at the required factory harness level but it is acceptable. Apparently some head were well  below the required hardness when new!. so I need top keep things cool.

I am going to put a much larger radiator in to try and keep the water running closer to 80 degrees and a  lower 86 degree fan switch to try and keep heat soak down when I stop the car

[SLR No.77]

To you both .... where are the temperature gauge senders mounted?

[Paul Mason]

Both the ECU and gauge sender's on rear of water rail above no.4, though my range is fairly stable between 80 - 85 usually so no worries for me

[SLR No.77]

Hi Paul, yes I suspected that's maybe where it is! You made the statement:

"On a cooler day, sticks more around 82. In traffic will rise,"

That's exactly the characteristics of a sender above no. 4 primary. With that being the case how do you really know what the temperature is when you're measuring coolant in a pipe that's being heated by the exhaust?

Stu.

[Jonathan Kay]

How about wrapping the sensor and rail to keep its temperature closer to that of the coolant and further from that of the exhaust?

That could both show the cause and remove the effect.

Jonathan

[SLR No.77]

How about just moving the sensor!

[Paul Mason]

I don't have an issue, I was merely describing my set-up and characteristics to Phil as a similar car. Get your point about location of sender Stu, but every car I've ever driven heats up when stationary and the fan kicks in? A product of airflow over the radiator rather than sender location surely? So whilst yes, moving the sensor would give a more accurate reading potentially, not sure I need to do it (plus, my mechanical skills and ability make me inclined to leave working bits well alone..........for fear that they may not end up being working afterwards)