Advice Sought - Water/Oil Temp relationship

[Graham King]

Folks, car is a 1.8Kss SL (fitted with an Apollo tank) recently acquired from Caterham.

 

I am looking for some advice on the coolant and oil temps, and specifically the relationship between the two.

 

The coolant temp rises to normal operating temp, approx 82 within about a mile, the oil will take about 6 miles (of gentle driving) to come up to a temp of approx 80-85. All the time the oil stays at this temp the water temp is fairly constant, whilst sitting in traffic the fan is able to control this fairly easily at about 90 and behaves in what I would describe as a normal fashion.

 

However as the oil temp rises so does the temperature of the coolant, the oil temp easily reaches 95-100 during spirited driving. At these oil temperatures the coolant temp is 90+ and the fan is cutting in during driving (judged as it is already running when coming to a halt), when at idle the fan appears to struggle to cope and can't seem to reduce the coolant temp (I have let the car idle for at least 5 minutes post blat, the fan was running the entire time and hadn't managed to reduce the temp).

 

All the above measured at an ambient temp of approx 20.

 

I have spoken to CC about this and they assure me everything is ok, but I feel uncomfortable that the coolant temperature behaves in this way.

 

So a few questions:-

 

1) Do I have a problem or is this behaviour normal 🤔

 

2) Would an increased capacity radiator alleviate the symptoms 🤔

 

3) Would an oil cooler provide an answer 🤔

 

Thanks for any advice.

 

Graham.

 

R7 GPK

Superlight #85

[Shaun_E]

All sounds pretty normal to me - those temperatures should not casue you any problems. You only need to worry if your coolant temp is consistently over 100 and the fan does not bring it down.

If you plan to do a lot of hot weather driving or trackdays then you will need a better radiator and possibly an oil cooler. Do a search for Radtec or Laminova and you'll find plenty of information on those.

Shaun

 

Yellow SL #32

[alan7]

Agree. Sounds pretty normal to me.

 

I've got a 1.6Kss with apollo & oil cooler.

 

Was out & about yesterday in the midday sun.

 

There is a relationship between oil & water temperature & one affects the other.

Took about 2 or 3 miles for water temp to get up to 78/80 & them gradually rises with the oil temp over the next 6 or 7 miles to run at 80/85.

 

Always takes that long for oil to warm up as there's about 8 litres of the stuff swilling round the engine/apollo & oil cooler. Neither gets much above 95 but occasionally rises to 100 on long hot blats like yesterday but soon reduces back down to 90/95 as the oil cooler thermostat kicks in & brings down the temperature of both.

 

An increased capacity rad or an oilcooler (in that order) would reduce the temperature of both. An alternative short term answer may be to fit a fan override switch to put it on earlier as the temperature rises.

 

Hope that helps & makes you feel a bit better

 

 

 

How do you get the dead flies off your teeth....... 😬 R5AAH

[Myles]

I can only speak from experience of a 1.6k with Apollo but (in no particular order):

 

i) Post-blat, my fan does not bring the temp down much when idling (ali rad) - but I'm not sure I'd expect it to. It's really only there (steps into deep water) to stop the temps going astronomical in low-velocity situations after all

 

ii) Overall coolant temp: I've fitted an 82 deg C thermostat to my car to let the radiator in on the action earlier in the game. It's hard to tell from the standard gauge (I've only got a SPA for the oil), but coolant doesn't seem to exceed 85-90ish (usually shows less than 80 unless in traffic after a fast section). In fact, my OT and WT correspond pretty closely - max OT is getting up to 87/88 degs C in this warm weather, but usually hovers around the mid-high 70s in sympathy with the WT.

 

Do you have an ali radiator? If not, I'd consider either the boggo ali caterham job (as I have) or the Radtec (slightly cheaper, possibly better) - but perhaps the first suggestion would be to fit an 82 of even 76 deg C thermostat.

 

An oil-cooler is all very well - but it shifts even more heat into the coolant system - so if your rad/thermostat/fan are not up to scratch first, you will almost certainly cause yourself problems.

 

 

 

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[Graham King]

Thanks for all the replies guys, I currently have the standard CC rad, so I think I will have a look at fitting the Ali race rad and change the thermostat at the same time. I would just be happier if things ran a little cooler, I don't like the idea of overheating, having heard of all the damage this can do.

 

Thanks again.

 

Graham.

 

R7 GPK

Superlight #85

[Myles]

Graham.

 

The 'race' rad is a chunky triple-pass job IIRC - it's expensive, and local rumour suggests it's not as effective as it should be.

 

The 'normal' ali rad from Caterham is much cheaper (IRO £200ish) and works well (it's a single-pass job) - but for the same money, you can get a Radtec which is (again, rumoured) to be more effective than CC's effort.

 

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