AUTOBOX W210. RUN TEMP. OPERATION. ?

[HERBIEMERCMAN]

hi everyone, i realise that the w210's must be getting thin on the ground now and the threads are diminishing, however the question i am posing could be a functional charachteristic of many merc automatic gearboxes. ?
it's a situation where the box plays up when it has reached its maximum working temperature, this occurs when you stop the car following say m/way run and the heat just soaks as there is no cooling air and no hydro oil being pumped into the oil cooler. if you leave the car for more than an hour then all normal functionality returns, but if you drive off after just 10 mins or so then the malfunctions occur, i mean things like sticking in first gear and somtimes trying to set off and there is a delay then the bump into motion. it's a rare occurance and despite regular oil and filter changes and this happening for most of the cars life this makes me think this is a charachteristic of these gearboxes. i use the "limp home" procedure for clearing the boxe's ECU and the normal box functions always return to normal.
my brother's car has an engine over-run feature to cool things down, turbo, autobox etc, this avoids the problem. any experiences like this out there. ? herbiemercman.

 

[television]

I think I would drop the valve block and check that the pistons are all not too tight.

My 129 would do this

 

[Frontstep]

I would start with basics of fluid level and quality then possibly a change.

 

[television]

Another listed fault is a poor connection on the CAN bus connector to the gear box ECU

 

[HERBIEMERCMAN]

thankyou malcolm / frontstep, where is the autobox ecu located. ? herbiemercman.

 

[television]

I have a feeling it is right rear of engine compartment on the bulk head

 

[Naraic]

It hasn't happened to me HM...so could be a fault with you car...check as advised above.

 

[Naraic]

I have a feeling it is right rear of engine compartment on the bulk head

Correct...unscrew the cover.

 

[HERBIEMERCMAN]

many thanks for the comments. i don't think it is the quality of the oil as it has been changed every 40k miles with new filter etc. from new. i am running a 10 deg. increase in engine temp with the rad blocked off as per dieselman's reccomendations, but remember the limp home only occurs very rarely following a m/way drive and shutting her down when hot.
the EGR mod was carried out on the nearside bulkhead compartment engine ECU, is this where the autobox ECU is located. ? herbiemercman.

 

[47p2]

You should not need to block off the radiator at this time of the year, in fact if your cooling system is up to the mark you should not even have to block off the radiator in the depths of winter, yes it may take longer for the engine to come up to temperature but it should still get there.

When I switch off the Tilly's engine the temperature goes from 75°C to almost 100°C (the boiling point of water) and as the cooling system is not pressurised there is a chance of boiling up, but even with these extremes it has not happened. This is down to old technology and different metals within the engine, modern cars should not suffer this as metals nowadays are much more compatible.

As for the gearbox problem, yes you might get a little 'heat soak' but not enough to cause a fault. Is the gearbox cooler in good condition and operating properly?

 

[HERBIEMERCMAN]

hi 47P2, thanks for comments, please see the link. http://forums.mercedesclub.org.uk/showthread.php?t=91421

not sure about the autobox oil cooler but i am confident it is working ok, had new pipes last year, also the failure mode for this is not blockage due to the sufisticated filter syst , the failure mode would be leaks from the matrix.
my car has an engine oil cooler inside the front N/S wing as well as the autobox oil cooler in the O/S wing, both have their own cool air entry grilles as does the intercooler matrix, none of these have been blanked off, just the engine cooling water system. the jury is still out on my hunch that the increased engine temp could spread to the autobox and just tip the "soak" i have described into malfunction territory. ? i will ask dieselman who has experience with the experiaments with this engine and running temp. herbiemercman.

http://forums.mercedesclub.org.uk/attachment.php?attachmentid=18310&stc=1&d=1332151084

 

[HERBIEMERCMAN]

the weather is now circa 20 deg so my temp gauge was showing 90 deg where it has previously run at 80 deg, SO i removed just half of the rad blanking and this has brought me to 85 deg, SO this seems ideal. i accept this is obviously more of a winter modification, much quicker warm up etc. herbiemercman.