360 - Heat Exchanger Leak? Gearbox/Coolant

Hi All,

I think my gear-oil heat exchanger has sprung a leak.

I have a 1~2mm thin film of milky beige fluid floating on top of the coolant in the expansion tank. The coolant level was also slightly higher than I would have expected. The car hasn't been used much since November. The last couple of times I've backed it out of the garage I've felt diff-chatter that hasn't be present since I started using Redline and have also found it a little hard to engage first gear from a standstill. I put these issues down to cool ambient temperature (circa +3 Celsius) but was preparing the car for a track day this weekend (wouldn't you know?) and on checking the coolant level found this problem.

I've dipped the gearbox for oil and it's a little low, lower end of the empty~full mark. It was perfect when I last checked maybe four months ago. There's no sign of contamination. Engine oil appears fine also, with correct level and no contamination evident.

I started the car with the cap off the coolant reservoir and almost immediately the level began to slowly rise and long before it was hot it was spilling over the neck.

So, what do y'all think? Is there any other likely explanation for oil contamination in the coolant?

 

^. Sadly, I think this is becoming too common.

From my very casual observation, we've sold more of them to the 360 cars than F355 (but they share the same exchanger), and most have been 'mid-miles' like in the 30k range from what I recall.

 

Greg

Is this the same issue as what the below product is trying to fix? I remembered reading about it but not sure how good it is?

http://www.dynamtechgroup.com/ferrari-tranny-cooler.php

 

I have replaced quite a few of these units recently, I am interested in seeing a pic of the aftermarket trans cooler set up.

 

I've replaced quite a few of these also. The cause is lack of coolant change, i've cut a couple open and found internal corrosion. I've also tried an external cooler but found no benefit. I secured a thermocouple into the cooler line and discovered that the gear oil takes way to long to come up to tempreture.

 

Thank you all for your contributions.

Hmm.... there's not a great number of threads on the subject but I'll defer to your statistics and the comments of those below also!

Yes, that would appear to be the issue and one potential alternative to the OEM system. That said the factory system has lasted 12 years on my car so I don't think I'll be looking any further for a replacement than OEM part.

Tech, Rusty, great to hear from a couple of Techs with experience.

First up, I guess.....Would you share my diagnosis or can you think of any other possible cause?

Any tips on flushing? Obviously my coolant system is contaminated and I haven't a clue what I might use to flush it in such a way as to purge the oil contaminant without potentially doing damage to seals etc.

From what I can gather there is no obvious contamination of the gear oil. I have noticed a slight difficulty engaging first gear from a stop and the return of slight chatter when cold and reversing on full lock but that could be down to the slightly low oil level. I'm thinking I've caught this in time and the gearbox is probably coolant-free or next to it. Thoughts?

Any tips on remedial action and/or parts required? I guess the intake manifold needs to come off which means a set of gaskets where they join the heads. Any other parts likely to require replacement in the process?

Interesting thoughts on the gear oil temperature Rusty. I've long wondered if this heat exchanger is as much about heating the gear oil as it is about cooling it. I would have thought that if the primary reason for it was to cool the oil that a more effective system could have been designed. After all, running the gear oil through an exchanger which is charged with coolant close to boiling doesn't sound to me like the most efficient means of cooling!

Any feedback very welcome!

 

Casey/Eddie -

I'm curious why they seem to fail on 360's more than F355 (at least from my *very* unscientific sales statistics). It could simply be a coincidence rather than correlation, but I'm nowhere near technical take a guess. Any ideas?

 

Sorry to hear of your woes mate. A coolant change has made it on my list of things to do though...

 

well my own view is that the 360's tend to cover higher mileages than the 355's, and certainly a fair portion of the 360's on my books have got either patchy service history or show signs of poor previous maintenance. 355's tend to be used a little less and so don't surcumb to the breakdown of the coolant's anti-corrosion properties. Well, that's my theory anyway...!
Ferraridublin-most likely the cooler...simple to check, just pull off the undertray and drain the gearbox, it will be full of coolant if the cooler has failed. If so,you need to give your cooling system a flush, but also pull your rear bumper off....when you drain the gearbox pull the little mesh filter out of the side of the 'box and give it a thorough clean. Replenish the oil then change it again after 50 miles, then again after 100. Same with the coolant, drain it off after a hundred miles or so and change it again. You will find your diff will start to make some strange noises for a while as the plates will have got gummed up with the coolant that's been induced, probably most noticeable when in reverse while applying steering lock....this usually dissapears after a hundred miles or so. Well noticed, by the way!

 

What's the best way to flush the cooling system Eddie?

Any recommendations on anti-freeze?

 

When you do a belt service on a 355 you have to remove the engine, and in order to do this you have to drain the coolant. Since the engine doesn't get removed on a 360 for a belt replacement, perhaps the coolant is not getting replaced at a normal interval?

 

I've just looked at the 360 service schedule and changing the coolant isn't mentioned!

 

Nothing unscientific about observing the replacement intervals between models.

 

And car guys change coolants every 2 years minimum. Which reminds me, I got to get to it with the 328.

 

It's difficult to really do a thorough coolant change on a 355. A large portion of the coolant is inside the block. The drain plugs on the sides of the block are brass with a relatively small hex socket. They don't come out easy and you're likely to strip out the hex first. I've found that the easiest way to get most of it is during an engine-out. You can easily remove the water pump assembly and reach in and suck quite a bit of it out. If you want to remove the plugs as well, it's probably a little easier then as well.

 

No coolant change recommendation is a problem on all late model Ferraris. You can maintain the car by the maintenance schedule and never change the coolant during the life of the vehicle. We are starting to see the results of this with the 456 and 550s in that forum and it will probably show up in the 575s eventually. Symptoms there are intenal corrosion of the radiator that is nearly impossible to get rid of without really draconian measures. Like Eddie said, the anti-corrosion inhibitors in the anti-freeze give up after a few years and the result can be nearly irreparably corroded pieces and built up deposits.

If the 360 heat exchanger is going, the radiator is seeing the same type of corrosion and will be a problem in the future, as several V12 owners can confirm. The coolant should be changed every 2-3 years at a minimum, and some pros prefer doing it annually. No idea why this important area of maintenance is ignored in Ferrari tech data, especially with components so susceptible to corrosion.

 

On the other hand, if you get 90% of the old coolant out, you have restored at least 90% of the corrosion inhibitors when the new coolant goes back in.

 

Ahh sure if it wasnt for the lousy timing (track day scheduled Saturday) I wouldn't mind so much. I was getting bored with it being so reliable and need to hone up my DIY skills!

Thanks - if it wasn't for the track day I might not have checked for a wee while yet. It seems I've been fortunate on this occasion in so far as there is not any evidence of coolant having entered the gearbox. The oil is a little low but no sign of any contamination. It's actually still a reasonably clean/golden colour as it happens!

The car has only been used for pretty short runs in the last couple of months. It's possible that generally speaking the pressure coming from the gear-oil line was generally higher than the pressure inside the coolant system and because of this the transfer of fluids only went the one way.

Agreed (on the radiator corrosion) but at least that's likely to mean you spring a leak which one would hope would be reasonably evident in terms of a pool of coolant under the front of the car. This lark of having the two different systems contaminated with each other is a right PIA!

I've had the car about 2.5 years now and the system was drained and replenished twice in that time. I guess it's quite possible it wasn't changed as regularly by the previous owners.

My biggest issue right now is what (if any) product might be best used to "wash" the coolant system of oil residue without doing damage to any seals etc.

Other than this, if anyone can suggest any additional parts I might need to order in advance of tackling this job I've be very appreciative. I presently have the exchanger itself and a set of gaskets for the inlet manifold on my list. Anyone aware of other items I will encounter on the way that are likely to require replacement?

Thanks to all for your input so far, much appreciated!

 

I think I'd forget trying to "wash" the system until you find the problem. If it's the gearbox oil you should find coolant in the gearbox. After the engine is shut off the oil pressure would quickly drop to zero (both engine and gearbox) but the hot coolant would still be under pressure for some time. Drain it and look. The coolant will do more damage there than oil in the cooling system.

 

Greg,

I'm sorry that this happened to your car! but...

Thank you for writing about it so we could get answers that will benefit everyone who encounters this. I know as my miles are getting higher and higher this is on the back of my mind. Remember it's just like any other car.. at least parts-wise. I think voicey's flush might not be a bad idea when you get a new exchanger in. If/when it happens to me, depending how badly I might just flush it with regular antifreeze a few times rather than get something potentially corrosive solvent into the block.

You guys think some alcohol might be beneficial for the transmission flush? to absorb the water? Or just boil it off with heating?

Taz, is there any component that you've seen that can serve as a corrosion indicator? For example the aluminum intake into the water pump? Corrosion on that = potential corrosion in the system/fins?

 

Curt- Not really on the V12s. The symptoms on the 456 and 550 tends to be mild overheating at first, which gets worse as hoses and other components also age. The radiator tends to get coated on the inside with deposits that act as insulators rather than radiators, and heat transfer capacity goes way down. We do sometimes see clogging in the small hoses that go to the coolant overflow tank, so that is worth checking.

 

Interesting. Thanks Taz!

 

Cheers Tim, I follow your logic and indeed it makes sense. If there is coolant in there I imagine it will become evident when I drain.

Not to worry, it's all fixable and them's the joys of motorin'

I'll probably not get to commence any work for a few days. Will report as I go!

 

The replacement heat exchanger is scheduled to arrive tomorrow so I started work this evening.

Drained down the coolant system and then flushed several gallons of fresh water through until there was no trace of coolant-colour in what was draining from the radiators. I ran the car while doing this in order to get the system hot enough to open the thermostat and hopefully ensure that the entire coolant system cleared out as fully as possible and took all that nasty oil reside with it.

Next up was to drain the gearbox oil which was also nicely warmed up by now. I haven't measured what came out just yet but colour was dark brown, not at all milky, and after a couple of hours settling in the drain container there's no sign of any separation of water from oil so it seems that whatever contamination there was from coolant system to gearbox was minimal. Jezz though, that gear oil stinks to high heaven!

Tomorrows task is to get the inlet manifold removed. Can anyone confirm it's possible to remove it without taking off the plenum covers? Any tips for removal gratefully received. What can be left on, what must come off, what can be simply moved to one side etc. Any tips as regards the fuel rails - release of pressure / safety issues?

 

YHM