Additional Gearbox Oil Cooler

[Clan]

you really need a thermostat with one of these so that it only cools when needed . has anyone actually monitored the temperature of their auto oil when towing? It is easily available with a £5 bluetooth device in conjunction with the "torque" diagnostic application which you can get on your phone .

The built in cooler in the radiator not only cools the fluid under hot conditions but usually forgotten it HEATS the fluid in cold weather ....

The gearbox does work differently with different oil temperatures there are 3 different control bands which are selected depending on the oil temperature The oil temperature is reported back to the electronic control computer . So when you say it "feels smoother" it may well be because clutches may be slipping more as the oil temperature is too low !

Water and condensation do form in the gearbox and it is essential that the oil gets above 100C regularly to boil off this water . It is not going to do that with a massive cooler in circuit all the time .

When you are driving at a constant speed over 50 mph the gearbox does not generate heat as it locks up and all turns as one and there is no torque converter slip which is what heats the oil up .

So basically Volvo know exactly what they are doing and what is best for your gearbox and what size of heat exchanger is needed and that's why they don't offer additional cooling ... If the gearbox oil is getting too hot it is going to affect the engine running temperature as that removed heat goes directly back into the engine .

Overcool you oil at your peril ! at least monitor the temperature it to see what is going on rather than guess . And it is normal to see oil temperatures of 120C when under load for a period ..... under normal conditions it will be around 90 to 100C ...


If you are doing serious towing in the Alps and the temperature goes up to 140C+ maybe an additional cooler would help occasionally but certainly not all year round ...

Gearbox oil overheating is not a problem in everyday use ...

[Danielpsmith]

Before I fitted mine I spoke to Volvo while I was there getting a few bits and they said to me you can’t cool the gearbox oil too much as it’s heat that kills them, I explained to them that mine was having issues and they said it was a good idea to fit the cooler.

But mine has done a lot of miles so is probably worn abit, it’s been on about 6 months and has helped a massive amount but time will tell through the winter I’m guessing.

[S60D5-185]

Originally Posted by Danielpsmith

Before I fitted mine I spoke to Volvo while I was there getting a few bits and they said to me you can’t cool the gearbox oil too much as it’s heat that kills them, I explained to them that mine was having issues and they said it was a good idea to fit the cooler.

But mine has done a lot of miles so is probably worn abit, it’s been on about 6 months and has helped a massive amount but time will tell through the winter I’m guessing.

+1


I'm more than happy to leave mine in situ.

Volvo made it for the XC90 and that's what it's fitted to.

I'm pretty certain that I have far more chance of overheating the box than overcooling it particularly when I have the van on the back.

[Clan]

Originally Posted by Danielpsmith

Before I fitted mine I spoke to Volvo while I was there getting a few bits and they said to me you can’t cool the gearbox oil too much as it’s heat that kills them, I explained to them that mine was having issues and they said it was a good idea to fit the cooler.

But mine has done a lot of miles so is probably worn abit, it’s been on about 6 months and has helped a massive amount but time will tell through the winter I’m guessing.

They obviously knew nothing about Volvo auto gearboxes

I had a case once with a 940, when towing it would blow all the oil out of the breather only in one particular place and only when towing . It was ok at all other times and yes IT HAD A BIG DIY COOLER in the line . It took a while to figure it out but it happened coming up the M5 from Weston to Bristol where there is a long uphill section . An oil change fixed it . It was the water which had collected when the gearbox oil was running too cold boiling off inside the gearbox as the oil temperature went over 110 C this was pressurising the gearbox and blowing the oil out of the breather .

Removing the cooler ( It already had a heat exchanger in the radiator so not needed ) and changing the oil cured it for good , he towed about four times a year and for a while had smells coming up that hill but he never realised what it was .

So the cooler the better is the completely wrong thing to tell anybody , the hotter the better within reason is best for the gearbox ...

[Danielpsmith]

I’ll just see what happens over winter I do a lot of stop start driving taking the kids to school and other running about and that can heat the oil a lot as well, like I said earlier my outlet pipe was as nearly as hot as the intake but since installing feels warm but nothing like it was before.

[Tannaton]

The oil is designed to run in the range of 100-120 degrees centigrade, that's when it's at the correct viscosity.

Below 80 degrees the TCM changes the gearbox parameters to warm it up more quickly - shift points are raised as are the torque converter lockup thresholds to create more slip and more heating. If you cause that to happen in normal driving by overcooling the fluid you will reduce economy and increase wear to the gearbox.

There's no great danger to the gearboxes if they run hot - it's long running, under load, with dirty oil that accelerates the wear to the clutches and changes the behavior of the solenoid valves.

Volvo did offer an oil cooler kit for the earlier AW55 geabox but only recommended it for 5-cylinder petrol models and only when heavy towing or in hot climates. The reason it was offered only on the petrol is they rev up to 50% more than diesel engines in normal use.

Your time and effort would be better spent changing the oil at 36k intervals if you tow rather than fitting a cooler. The gearbox fluid is monitored and it will tell you on the dashboard if it starts to get too warm.

[galloot633]

My 06 d5 185 started flaring 3rd to fourth about 6 years ago ( approx 100k miles) it got progressively worse over the years , until it was finding false neutrals and putting the car into limp mode about 3 years ago. a fluid flush made absolutely no improvement, ironically an engine oil change made a slight improvement to the gearbox, which made me start thinking the engine was transferring heat to the gearbox fluid. I understand volvo designed suitable heating/cooling of the fluid as the car was new, but I believe as the cars go over 100 k this isn't true anymore , here's a link to the genuine volvo cooler for my model, note no thermostat is recommended.
https://accessories.volvocars.com/en...utomatic/R.H.D
ps , my car has now done 180k , uses no oil and runs perfectly ( before someone suggested its clapped out )
Dave

[Clan]

Originally Posted by galloot633

My 06 d5 185 started flaring 3rd to fourth about 6 years ago ( approx 100k miles) it got progressively worse over the years , until it was finding false neutrals and putting the car into limp mode about 3 years ago. a fluid flush made absolutely no improvement, ironically an engine oil change made a slight improvement to the gearbox, which made me start thinking the engine was transferring heat to the gearbox fluid. I understand volvo designed suitable heating/cooling of the fluid as the car was new, but I believe as the cars go over 100 k this isn't true anymore , here's a link to the genuine volvo cooler for my model, note no thermostat is recommended.
https://accessories.volvocars.com/en...utomatic/R.H.D
ps , my car has now done 180k , uses no oil and runs perfectly ( before someone suggested its clapped out )
Dave

you might be interested to know that there IS a water cooling thermostat fitted to the gearbox from about 2015 when the 8 speed gearbox was launched ...

[Tannaton]

Originally Posted by galloot633

My 06 d5 185 started flaring 3rd to fourth about 6 years ago ( approx 100k miles) it got progressively worse over the years , until it was finding false neutrals and putting the car into limp mode about 3 years ago. a fluid flush made absolutely no improvement, ironically an engine oil change made a slight improvement to the gearbox, which made me start thinking the engine was transferring heat to the gearbox fluid. I understand volvo designed suitable heating/cooling of the fluid as the car was new, but I believe as the cars go over 100 k this isn't true anymore , here's a link to the genuine volvo cooler for my model, note no thermostat is recommended.
https://accessories.volvocars.com/en...utomatic/R.H.D
ps , my car has now done 180k , uses no oil and runs perfectly ( before someone suggested its clapped out )
Dave

That's the one.... fitment guide is this:

Engine Transmission Need for oil cooler Part number

All MT no

2.5T AT yes 8685834

I5D AT no

3.2 I6 AT no

V8 AT no 307927172

Remember the V8 uses the later TF80 six speed, the 2.5T the earlier AW55 5 speed