Why no oil cooler?

[poorpeet]

I have always wondered why, if the underbonnet temps are so high, no oil cooler was fitted & no one ever mentions them on here?

[chassis 33]

I'd imagine its because there's no real need for an oil cooler, modern oils can survive well over 100oC before they have issues, and also the sump in a fashion acts as something of a cooler, being a big lump of oil sat in an air flow. If you look at say an old A-series Mini engine the sump is finned for just this reason.

Regards
Iain

[spend]

My oil lasts a lot longer with oil cooler & I am convinced it aids with cooling - as oil cools when good airflow & doesnt contribute to heat mass when you hit traffic. Just my 2p....

Dave

[markh]

chassis 33 said:

I'd imagine its because there's no real need for an oil cooler, modern oils can survive well over 100oC before they have issues, and also the sump in a fashion acts as something of a cooler, being a big lump of oil sat in an air flow. If you look at say an old A-series Mini engine the sump is finned for just this reason.

Regards
Iain

I have oil coolers fitted to both of my Chimaera's, and found the oil stays a more constant temperature and also keeps the pressure up as well

[spend]

Oil temp is above 100c when car is used, dont get confused with water temp. It is known that it is high temp & pressure which breaks down the chain molecules in oil (belt & braces understanding) ~ preventing these extreme circumstances is what keeps your oil in better condition (& thus working properly) for longer. Dont stress your synthetic oil & it will last much longer (just subject to crap from cylinders escaping and contaminating it) IMHO.

Dave

[victormeldrew]

I have an oil temp guage on my Chim, with a sender plumbed into the sump plug. You'd be surprised how cool the oil runs generally, and often in inverse proportion to coolant temp. Oil needs to be hot to work, and other than track days and illegal motorway yomps it rarely gets hot enough to warrant a cooler - its often down as 70C, which isn't hot enough really. I'd consider a oil/water "cooler" as a way to get oil up to temp quicker, but I doubt that one is needed to keep oil temps down.

Incidentally, oil temps tend to drop in start stop traffic, even when the coolant temp is nudging three figures, as shown on my guages.

Edited by victormeldrew on Tuesday 16th January 18:56

[spend]

Phil, sump plug is not ideal as that is where oil is cooled (in the sump) as well as the sensor being in cold air flow. I would also add do not fit a cooler without a thermostat - these typically only open @80c to use the cooler. Maybe I should have stressed my term 'used' as more on the thrashed, but as said earlier if your pressure is dropping after slowing it is a sign of the oil having been stressed.

Dave

This had better get rid of that bloody porch advert to my right!
Jesus, Now its a Lotus one! try again

Bugger its a porch one again

Edited by spend on Tuesday 16th January 19:49

[markh]

victormeldrew said:

I have an oil temp guage on my Chim, with a sender plumbed into the sump plug. You'd be surprised how cool the oil runs generally, and often in inverse proportion to coolant temp. Oil needs to be hot to work, and other than track days and illegal motorway yomps it rarely gets hot enough to warrant a cooler - its often down as 70C, which isn't hot enough really. I'd consider a oil/water "cooler" as a way to get oil up to temp quicker, but I doubt that one is needed to keep oil temps down.

Incidentally, oil temps tend to drop in start stop traffic, even when the coolant temp is nudging three figures, as shown on my guages.

Edited by victormeldrew on Tuesday 16th January 18:56

You surprise me, I also have a separate oil temperature gauge and while I agree with you with normal driving I have seen temperatures of in access of 130+ on track days and 110 on touring in Italy, so I reckon the oil cooler is worth while investment.

[GreenV8S]

In this engine the oil and water have plenty of opportunity to exchange heat so the oil gets plenty of cooling directly from the water. I don't think many people would need an external oil cooler, very few road cars would and not many track cars. I have one on mine (in fact just changing from oil/air to oil/water) but I don't think most people need it.

[spend]

What you doing here Peter, you were still on stage in the pantomime last time I looked :-/

hehehehehe we all left leaving you looking behind. Dont worry Daddy wont be able to resist getting the last word in (cant believe hes lasted out this long)

Dave

[victormeldrew]

markh said:

victormeldrew said:

I have an oil temp guage on my Chim, with a sender plumbed into the sump plug. You'd be surprised how cool the oil runs generally, and often in inverse proportion to coolant temp. Oil needs to be hot to work, and other than track days and illegal motorway yomps it rarely gets hot enough to warrant a cooler - its often down as 70C, which isn't hot enough really. I'd consider a oil/water "cooler" as a way to get oil up to temp quicker, but I doubt that one is needed to keep oil temps down.

Incidentally, oil temps tend to drop in start stop traffic, even when the coolant temp is nudging three figures, as shown on my guages.

You surprise me, I also have a separate oil temperature gauge and while I agree with you with normal driving I have seen temperatures of in access of 130+ on track days and 110 on touring in Italy, so I reckon the oil cooler is worth while investment.

"other than track days and illegal motorway yomps"! I haven't taken the car abroad since fitting the gauge so I can only comment on UK use. No doubt in a few years with climate change I'll have to revise my opinion, but since there won't be any oil left by then maybe not.

Dave - yes, the sump plug is in the airstream, but since there isn't much airstream in start stop traffic I don't think that fully explains why the oil temp drops in this scenario! Considering the speed with which oil temp rises at full chat I'm sure it's measuring oil temp and not adversely affected by ambient. I keep meaning to validate the reading with a laser just to be sure. I'd prefer to take the temp from near the oil filter as it comes out of the engine, but I suspect the difference wouldn't be much.

[that daddy]

Spend i just looked at your remark,i must say im hurting real bad,and no i have nothing to say on the previous post and thats not often, thought i would sneak out while the coast was clear.Getting back to this one as Green V8s an i once agreed,we do like the water/oil cooler heat exchanger type cant say my road use would warrant one though + of course you would be transferring more heat into the rad thats overstressed already,he,he oh im not going down that road again(see rad fins)for that one.

Edited by that daddy on Tuesday 16th January 21:12

[spend]

that daddy said:

Spend i just looked at your remark,i must say im hurting real bad,and no i have nothing to say on the previous post and thats not often, thought i would sneak out while the coast was clear

What you mean I have to goad you to win the bet?

that daddy said:

Getting back to this one as Green V8s an i once agreed,we do like the water/oil cooler heat exchanger type cant say my road use would warrant one though + of course you would be transferring more heat

Relative cost of laminar & simple rad are vastly different >x10 as I remember, I dont think this is cost effective for most, but certainly agree with accelerated warm up of oil (Peter & I have been on opposite sides on this before IIRC, but if I bladder on long enough?)

that daddy said:

into the rad thats overstressed already,he,he oh im not going down that road again(see rad fins)for that one.

Oh yes you will (and you know it :-)


Phil, I dont think it makes a lot of difference temp sensor in the sump plug or at the gallery by the oil pump they are all getting oil from the 'cooled' reservoir (sump). I'd guess the thing you are trying to prevent with an oil cooler is the extremes seen (after the oil pumps just given it a goood thrashing) at the bearings & I dont think its a feasible challenge for us to be able to measure that, only to speculate. Definitely agreed 99% of the time an oil cooler is uneccessary ~ but its those odd times you are allowed to let the beast out you dont want to have to stop to cool down (particularly with a single finger from a Porsche driver dwindling into the distance). Secondly because of these reasons I dont see any conflict between putting oil cooler in front of rad - oil will only be cooled when you are getting ample air flow thru rad and a thermostat should prevent any overcooling of the oil.

Dave

[That Daddy]

Spend,i will agree the rad type cooler is better at loosing heat,but the water/oil unit as more benefits but expensive,but for a track car i would use the rad type for maximum heat disapation,with a stat of course.

[spend]

Dont get me wrong on this chaps, I would have loved a laminar cooler, but in the cold light of day thought the money saved would be better put towards an accusump (still want one) ~ mainly for cold starting protection.

After experiencing / contemplating the benefits of the rad type cooler I would probably now buy in preference to laminar. Warming up the oil / engine is a good sanity check so tyres etal are upto operating! Oil only needs to be cooled in bursts (it heats up very quickly for a short time) normally or requires a lot of cooling if you are on an extended thrash and with the benefit of hindsight I suspect the rad type cooler is better suited.

In balance I installed the rad type as a compromise, but have come to think it may be more suitable than the laminar type anyway.

Dave

[That Daddy]

Spend, that accusump i would say would be put to good use on the RV8 anything that helps camshaft pre/start oiling as got to a bonus.

[Bensonv8]

poorpeet said:

I have always wondered why, if the underbonnet temps are so high, no oil cooler was fitted & no one ever mentions them on here?

IMO
The excessive heat under the bonnet is caused by the 2 massive exhaust manifolds and the big curly 2 into 1 exhaust bit in front of the engine, before it disappears under the car.
An oil cooler wont cool down the exhaust system.
It might even transfer more heat under the bonnet

[markh]

Bensonv8 said:

poorpeet said:

I have always wondered why, if the underbonnet temps are so high, no oil cooler was fitted & no one ever mentions them on here?

IMO
The excessive heat under the bonnet is caused by the 2 massive exhaust manifolds and the big curly 2 into 1 exhaust bit in front of the engine, before it disappears under the car.
An oil cooler wont cool down the exhaust system.
It might even transfer more heat under the bonnet

Had mine ceramic coated, cut the under bonnet temp down by a huge amount

Edited by markh on Wednesday 17th January 19:35