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Gearbox Oil Cooler - A Warning...

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David Hallworth   
Tue Oct 29 2019, 11:54am

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
Over the last few weeks my 407 Coupe 3.0 HDi has started to tug between gear changes on the 2 - 3 and 3 - 4 when changing up. The other changes were still very smooth. I check my levels weekly and noticed nothing wrong and nothing particularly untoward when it started. However, due to work and weather I hadn't checked them for a fortnight this time around.

I'd done a lot of reading on the net and had convinced myself that the fault with my gearbox was valve block related as these Aisin Warner boxes do seem prone to valve block issues.

Last night I decided I was going to get the car in the workshop and onto the ramp and remove the valve block. However, upon opening the bonnet I immediately noticed the coolant bottle had turned brown. When taking the cap off it, it was full of sludge and it stank of ATF. I was certain at this point that the oil cooler had failed.





I took the undertray off the car and got a job, I then removed the sump plug from the gearbox and the [%*^#@!] that drained from it was disgusting.









My car had the coolant flushed and changed when the thermostat housing was done in May and at the same time it had 2 gearbox oil changes done also.

I then removed the oil cooler and blanked one of the coolant ports with my thumb and blew down the other. I could hear air escaping from the oil side so it's definitely got a hole in it.

Looking online, the oil cooler is £480 from Peugeot/Citroen. To flush it properly will cost a couple of hundred quid in oil, and my cooling system, radiator, heater matrix, etc. is all now full of an ATF/Coolant sludge so that's gonna take hours to flush.

I've also been told that these gearboxes despise having water in them and that even if I persevere and sort it, there's a good chance that it won't last anyway. I'm now faced with the dilemma of stripping the car for parts or spending £2.5k on a gearbox rebuild.

Seeing as it's the same gearbox on the C5/C6/407/etc. it makes me wonder if these oil coolers should be considered a service item at circa 100k to prevent catastrophic failure.
1 User said Thank You to David Hallworth for this Post :
 cruiserphil (29 October 2019)
Hattershaun   
Tue Oct 29 2019, 01:39pm
Joined: Dec 19 2010
Member No: #320
Location: Bedfordshire
Oh dear!
Worth talking to an autogearbox specialist for advice, might be worth taking the chance of replacing the cooler and flushing the oil systems, especially if you do the work yourself.
C6Dave   
Tue Oct 29 2019, 03:42pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
It's the same part number for the 2.7 HDi as well as the 3.0 HDi used across the PSA range and probably Jags as well using the engines/gearboxes?



How do they justify £480 for it?

You can get one marginally cheaper here: Peugeot Citroen Parts

I can't remember seeing any other posts about a failed oil cooler though on a C6?
Website
1 User said Thank You to C6Dave for this Post :
 cruiserphil (29 October 2019)
MGmike   
Tue Oct 29 2019, 04:13pm
Joined: May 21 2017
Member No: #3151
Location: South Queensferry
Dave, I have a couple of box’s you could take one off for beer money if you are so inclined?
They’re in East Calder ...
Regards
1 User said Thank You to MGmike for this Post :
 David Hallworth (03 November 2019)
David Hallworth   
Tue Oct 29 2019, 04:37pm

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
I've spoken to a Citroen specialist who has witnessed the same thing on 3 C6's and he said the boxes don't last when they've had water in them.

I rang a local gearbox specialist today wondering if they could powerflush it to remove every drop of water from it in the hope it might help it last rather then partial changes and they said they would take my money if I wanted them to, however, they don't recommend it. Apparently once the boxes have had water in them the friction materials just break up and disintegrate. The only option as far as they're concerned is a full rebuild.

To remove, rebuild and refit the gearbox they want £2,500 + VAT and then the cost of an oil cooler on top of that.

In reality I'm looking at £3k + VAT so unfortunately the car isn't really economical to repair.
MGmike   
Tue Oct 29 2019, 05:12pm
Joined: May 21 2017
Member No: #3151
Location: South Queensferry
Dave, can I have first refusal pls.
I have YR56’s box I could put in a body that isn’t a Cat C!
David Hallworth   
Tue Oct 29 2019, 05:15pm

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
No worries, Mike.

I do have a plan at the moment which means I might need the engine... Long story but I should know fairly soon.

David.
onthecut   
Tue Oct 29 2019, 05:40pm
Joined: Sep 20 2016
Member No: #2793
Location: West Mids
Mmmm. Not the most cheerful of threads !

Do you have a theory on the cause of the failure ? The only logical reason I can think of is inadequate anti freeze / corrosion inhibitor on the water side allowing corrosion to develop, leading to perforation. Alternatively, is there some inappropriate mix of metals in the cooler leading to the failure ?

Mike.
David Hallworth   
Tue Oct 29 2019, 06:41pm

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
I've no idea to be honest.

I bought the car when it was 6 years old with a full Peugeot history. The timing belt and water pump were done on the car by a Peugeot dealer 2 years before I got it too.

A month after I got it I replaced the air con condenser and drained the cooling system. I flushed it completely and refilled it with a 50/50 mix.

Then 6 months ago I replaced the thermostat housing, flushed it and again refilled it with a 50/50 mix.

I really don't think it was a bad mixture of anti freeze that caused it unfortunately.

If I find another, I'm going to change the oil cooler as part of it's maintenance though.
MGmike   
Tue Oct 29 2019, 08:13pm
Joined: May 21 2017
Member No: #3151
Location: South Queensferry
David Hallworth wrote ...

No worries, Mike.

I do have a plan at the moment which means I might need the engine... Long story but I should know fairly soon.

David.


ooo sounds interesting
Fraunie   
Tue Oct 29 2019, 10:10pm
Joined: Dec 09 2018
Member No: #3763
Location: Stockdorf
"Then 6 months ago I replaced the thermostat housing, flushed it and again refilled it with a 50/50 mix."

Have you used the recommended G33? You can get it only as original PSA-Product....
speedfix   
Tue Oct 29 2019, 11:05pm
Joined: Sep 28 2012
Member No: #1043
Location: south west
Did you use distilled water?
Another cause can be electrolysis! maybe worth a test.
A weekly check of the under bonnet levels can be a worth while job.
- Click Here -
1 User said Thank You to speedfix for this Post :
 cruiserphil (30 October 2019)
David Hallworth   
Wed Oct 30 2019, 10:54am

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
When I bought it the anti freeze in it was pink and the timing belt hadn't long since been done by Peugeot in Lincolnshire.

When I changed it 3 years ago I used this:

- Click Here -

When I changed it 6 months ago I'd run out of the above so used this:

- Click Here -

From what I can work out, G30, G33, G34, G40, G44 should all be compatible with each other. I've used this Millers Oils OAT stuff in Range Rovers with aluminium blocks and aluminium oil coolers for 15 years and have never had a problem. I didn't use distilled water as we're on a private water supply with no additives in it and it's tested annually for bugs/metals/contaminants.

I think I've just been unlucky and from speaking to a Citroen Specialist and a gearbox specialist it doesn't seem to be an uncommon failure.

When I finally source a replacement car, I'm going to replace the oil cooler for my own piece of mind.

David.
1 User said Thank You to David Hallworth for this Post :
 cruiserphil (31 October 2019)
David Hallworth   
Wed Oct 30 2019, 12:08pm

Joined: Apr 16 2010
Member No: #90
Location: Glasgow
Edit - I've just remembered I asked Millers Oils technical for coolant for the car and I've just found the email they sent me.

According to them the coolant that the car needs is PSA B71 5110. The Millers Oils Alpine Extend Red that I linked above is the correct anti freeze for the car so I'm happy it was on the right anti freeze.

David.
2 User said Thank You to David Hallworth for this Post :
 C6Dave (30 October 2019) , cruiserphil (31 October 2019)
Fraunie   
Thu Oct 31 2019, 04:33pm
Joined: Dec 09 2018
Member No: #3763
Location: Stockdorf
As mentioned, I have just bought 15 litres of the original PSA G33 and the color is BLUE/GREEN...
(Btw it is not expensive, 5 litres (ReadyMix) were about 14 €)

I can't say if the one from Millers is compatible.

There are ones which are containing silicate and others that don't.
You definitely shouldn't mix one with and one without silicate!
That might cause acids, which can affect metals in your cooling system/engine.
G30 for example is silicate-free. G48 is a silicate type.

Well they are mixable, of course, but for the better or worse...
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