Why You fit an Aux Trans Cooler to an 850 / V70 / S70 / C70

[CNGBiFuel]

Being hard on an engine with excessive rpm when cold is never good and your 'slush' box won't like it either, but ATF that is a little cool is not going to harm your box. After all, you do that now. because until you've done 30-35 mins of fairly brisk miles on all but the hottest of days, it'll still not be up to the ideal 80-90 degs range. And how many of of us can honestly say, 'all' their mileage is greater than that 30-35 mins warm-up period?

So a little cool is not an issue, whereas heat is a killer. Dip your box, and if you see black fluid, change it and be sure despite the hassle to get the level spot-on.

[Brianjone5]

CNG - useful post - thank you. You mention changing transmission fluid annually after 40,000 miles per year, wow!

Do you drain and replace, diluting the old fluid. Rinse and repeat. Or do you turn the engine on briefly to pump fluid out, catch, measure and replace?

I am about to do this, and I'm sure you have more practice than most?

[CNGBiFuel]

Flushing: This subject has been done to death, which is why I did not cover it here. Google "Gibbons Flush" and add my points already made in this posting. ie about jacking. Use the correct fluid, Carlubes 3309 is fine. Mannols (non-syth) if you must. You do not need Mobil 1 etc. It's a Toyota Aisin Warner box so maybe see yoru local Toyota dealer. This box is known to die because of Volvo's lifetoiem fluid claims.

Fluid level is critical and a pain to get right.

A decent slush-box is good for 150K, certainly if fluid gets changed every 40-60K odd, likely far more,. The reason the fluid should be changed is that it is usually burnt and far from that rose-pink by 70-80K. The box will limp on for another 40-50K, even if the manufacturer makes lifetime-fluid claims. The thing is, UK drivers don't usually get found out because our cars don't do high mileages, so don't truly wear out, but get thrown out.

Coolers stop fluid burning. Almost all the slush boxes I've ever seen meet their end via black (& burnt) fluid because they were allowed to limp on. i.e. used past the fluid burnt point. This is when all the wear sets in. Fluid kept cool or changed will result in that 150K figure increasing to 250K+. In the US you'll see slush-flush-shops precisely because cars won't get to the end of their life on the same ATF where galactic milaegaes are common.

The typical vehicle doing UK mileages hits the breakers-pile before most slush-boxes meet failure. Certainly by the time fluid-failure becomes an issue. Whereas if you tootle about like the typical UK driver, it'll likely not be an issue. Snob value will see it on the breakers-pile before box failure.

It's about the mileage cycle. Here the first user of a typical new car does 25K a year for 3 years (via its first business user) and then it hits the second-hand market at which point it does 10-12K pa therein. The Yank cycle is more like 45-50K and 20K respectively. Walk round any Yank used car lot to see what I mean. Galactic miles will be seen as low.


Of course there will be exceptions, but generally fluid changes are the route to long-life of anything mechanical, and your slush is no different. Mine has 270K on it, how much of that figure is down to frequent fluid changes i can never say. A fair bit I reckons. My box runs like new, and unlike the box with half that mileage but black p*ss for fluid why wouldn't it?

[doingitsideways]

Sorry to jump in, but is the Toyota 'box the 5spd?

Just bought a C70 to add to the collection and want to do a flush with the right fluid.

[CNGBiFuel]

Yes the five speed box needs the particular fluid listed in this posting. You might be one of hte lucky few with a aux. cooler already fitted. I understand, the gruntier C70 got these standard. If your ATF is anythign other than a red or a very dark plum on your stick, change it. Black?? Get rid.


Fluid level is really awkward to get right and is pretty critical too. Best doen at 80 degs, I find that at 40 degs it is easy to get wrong, and 80 degs takes ages to get that hot. A right PITA. (Read this posting for info on this)

Listen to Volvo and they'll tell you 'Sealed-for-Life' but then they would. The only good a 200,000 miler C70 is to them is in the maarketign blurb for new car-buyers, because it sounds good - the very buyers that won't be keeping their car that long anyway. Your only function from their standpoint, is to buy parts at dealer rates, and I suspect you don't do too much of that?

When did anyoen reading this thread last hit their dealer with a £35-40,000 cheque? No, me neither. If you take my piont, like me you are not a Volvo owner.

[classicswede]

I did not like the fitting used for the cooler pipes into the rad on the P1 so changed things around fitting new to air coolers







I used LPG fittings as pipe as I had them to hand

[CNGBiFuel]

Classic young man, that looks like the no messing, no pistolling about proper job...

Although the inbound stock cooler does warm the ATF, and all external it won't.
Put a Magnefine in. I did.

Agreed, those fittings are not up to much but do work. I grabbed heaps of the things from Lakes when I raided their yard, the trick in removing them without breaking the turquoise plastic barb clips is to push in and squeeze, oscillating the things turning gingerley for 2-3 mins to free them off before you attempt any pulling.

As I said I was doing the engine coolant radiator too, so got to play with them, you can repalce them with 3/8" NPT barbs. See pic. Might be easier too, particualrly, if your trans-cooler is something you've cobbled-up. Then again, if you're an LPG installer with shedloads of fittings, and pipe-benders etc etc, you might not.

me? i unscrewed the female fitting from my old inbound cooler and nailed it to my stat to make it easy to pipe-up using my new stash.

[classicswede]

The P1 fittings are much worse. The filter is not a bad idea. I would rather suffer a little loss of warmup over the risk of failed oil hose connection.

[CNGBiFuel]

In short, these boxes are undercoooled. As the ATF burns, I've yet to see a car with much over 50,000 that has ATF even remotely pink. The boiling point goes down as it burns. In downward spiral, as the boiling point drops, the fluid burns still more, evidenced by it getting blacker still. Ultimately this means bye bye box. The earlier P2 cars have a box / vlave body particularly sensitive to temperature and less than A1 ATF. It's under-cooled. Many make it to stellar mileages, but those that don't, by the time owners see the issue, the old now burnt ATF has been left too long. An ATF change is no longer the cure.

Volvo are aware of thsi and tacitly admit this point in their service documantation. They do it because the cooling has been designed to last inside the warranty, and make ATF or a gearbox a service item outside of it. If every owner started doing 250,000 on their cars, with trans designed and cooled to last much longer, they'd sell a lot less cars, gearboxes, or simple ATF changes in their dealer network. Volvo need to give their dealers business. You pay Volvo a lot of loot to run a dealership, and dealers want their money back.

eg: there are advantages to cams having belts, but the main reason for cams being belt driven is dealer driven. Chains run for 200,000 miles + in heavy goods vehicles. So HGV gets chains. An HGV vehilce might still be in warranty at 200,000. Only a typical Volvo customer is at the tale end of his warranty at this point, and belts are a nice service item that needs doing at jsut the kind of mileage, where warranty is not an issue, and belts are cheaper to manufacture than chains anyway. So the two of them, dealar and manufacturer are happy. Best of all, if they're not changed, they're all good fun. What's not to like?

And when the cambelt is due, you're in a haze of joy too

Or am I being too cynical?

[CNGBiFuel]

I forgot to say, fitting hte Derale stat I drilled two sets of mounting holes in teh battery tray. Outer just to hold everythoing steady (as my pics) whislt I did my plumbing, but anotehr set further back, after plumbing so that stat does not foul the battery retaining clip that fits to the tray.