The V8 Owners Forum -

Is there a rule of thumb on when to fit an oil cooler?

Although I've had radiator cooling issues (not keeping things cool enough) now hopefully solved, my oil temperature gauge runs at 100 degrees and 110 on hot days / motorways. OK, my gauge may be out but CAI had my gauge and (supposedly) matched my sender to it so I can only assume it is correct.

If you are using good quality oil then 100-110 is ok. My VXR8 (ls3) would go up to 120-125 when driving it hard and that is considered OK.
The Dakar gets quite hot, but it's running Silkolene pro-r and also has a cooler.

There's been some recent discussion about this on the SD1 Forum. As my SD1 - an EFI - has a factory fit one, while the Vitesse with the same engine doesn't. It didn't seem to be linked in with air-con either, as both models can have that. Or auto, as again both models could be auto. Export models destined for hot countries had a larger air con aux fan - so it doesn't seem to be to do with ambient temp.

One member with an EFI fitted with a 4.6 engine has fitted a thermostatic valve to his cooler, as he was concerned with over-cooling.

Did TVR fit one?

Dave, I don't have an oil cooler so am wondering if I need one. My TVR Griffiths500 donor did not have a cooler but then the engine is now in a different car and so presumably does not get so much natural cooling as in a TVR.

My rad has not been cooling the water enough to date and so I presume that would have an effect on the oil temp making it run higher than it should. Having now sorted the rad cooling I'll be checking the oil temps but was wondering what the threshold is.

I will be using Mobil 1 (fully synthetic 0/40w) oil as that is what TVR state is the oil to use (and have read many of the 'which oil' posts on this Forum but decided to stay with what TVR say).

Sure it will open a can of worms but I thought modern synthetic oils didn't contain the best additives to prevent camshaft wear? Modern engines being OHC having less loading on the cams?

Oil temp, there's a general rule of thump.
Oil temp should be within 10% of the engines water temp.
Also counts for automatic transmission fluid.

125'C is considered not good as Real Steel advised me to mount a 16 row cooler with stat when I showed up with that temp on my gauge.
Oil even semi synthetic gets very thin at that temp causing a loss of oil pressure also.

That sounds similar temps to mine although I think mine only creeps up to 105/110 when stuck in traffic. I also have a large intercooler across my rad, but I do have a winged sump which may help cool the oil when driving.

I haven't got an oil cooler and was also thinking 'do i need one?' At the moment i'm happy that I don't. I also use good quality full synthetic. If I was regularly getting 115+ I would probably think about using a 50 weight oil, and or an oil cooler (with stat)

Tom.

Hello Richard,

In general the original (shall we say) SD1 V8 set-up of cabin heater, radiator, thermostat, cowelled viscous fan and Aux fans - if fitted - is perfectly capable of overcooling the engine.

It is the responsibility of the thermostat and the viscous fan to, jointly, control the coolant at a stable temperature.

As fault conditions develop then, clearly, cooling ability is degraded.

Smaller radiator and un-cowelled fans, likewise. Restricted under-bonnet airflow - ditto. Thermostatically controlled electric fans also have their issues.

The fault conditions being - air locks, crud deposits in the rad, coolant galleries in the block and heater matrix, eroded water pump impeller blades, unreliable stat, etc.

Therefore, before considering any additional cooling aid, it seems prudent to be absolutely sure that all the cooling system components, pipes, galleries, pump, stat, fan and etc, are all working at 100%.

If, then, and only then, the system still has a cooling problem one might consider the additional oil cooler.

Even then such a cooler adds an additional maintenance responsibility of timely flushing, particularly as it is at a very low level.

I have an essay that contains many more of my RV8 'stable' cooling system thoughts, you may be interested.

http://www.vintagemodelairplane.com/pag ... ing01.html

Many thanks for the above from all and all seems quite clear. Ramon, my set-up is quite different but I take your points and especially your interesting PDF. As a result, I'm not jumping immediately into fitting an oil cooler not least at finding a mounting place in my nose cone!

The first albeit short run out today following sorting the radiator seems the engine is keeping around 82 - 85 and the oil almost reached 90. So far so good but need to check this out over the next few days or so on longer and faster runs.

Thanks again.