engine overheating at over 40mph

[johnro79]

hello again


first time i've seen the coolant error. driving on M25 at 40-50 and when it cleared up i've tried to went up to 60.
then when light and warning came on: coolant too high ...
no major coolant usage, just maybe 300ml over 4years

i'm due for a timing belt and water pump anyway so i went on ETKA and tried my luck with part codes

WAUZZZ4G6EN078816
a6 c7 2.0 tdi 177 270k miles

this one got me confused: what's the difference between 03L121011J and 03L121011JX . i believe newer ones are 03L121011P and 03L121011PX
what is the X for ?

also, reading about faults and bulletins online, i've decided to replace the Thermostat too with a latest development one. is this the one i have to look for: 03L121111AD ?

my next confusion is with Bosch timing belt kits.
i've found 2 of them with different bosch part numbers but they bot fit (so they say).

how do i tell which is the right better one for my needs?


i'll try and run vcds today to see if there are any fault codes stored in regards to water pump/cooling
anyone could pls advise on which tests/reading should i perform in there to be able to test what parts might be wrong?

[dean warren]

Get a price on genuine stuff, J or JX or p or PX the ex can mean its an exchange item.


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[johnro79]

Hi
Thanks for the input

Right now I'm trying to find the right part codes for my car.
I won't buy repairs or dodgy brands anyway

[VAG-Abound]

this one got me confused: what's the difference between 03L121011J and 03L121011JX . i believe newer ones are 03L121011P and 03L121011PX
what is the X for ?

The X usually denotes a rebult part - stripped, worn / wearable parts replaced, should be as good as new.

The P suffix seems to be listed as a later version for various non-Audi vehicles (where a J will also fit), while the Audi's stick with J. Sticking to something compatible with J may be best.

also, reading about faults and bulletins online, i've decided to replace the Thermostat too with a latest development one. is this the one i have to look for: 03L121111AD ?

That seems to be the right one. Can you read the part code on the existing one?

my next confusion is with Bosch timing belt kits.
i've found 2 of them with different bosch part numbers but they bot fit (so they say).

how do i tell which is the right better one for my needs?

One of them has a water pump, the other doesn't. Does that help you choose ?

[johnro79]

One of them has a water pump, the other doesn't. Does that help you choose ?

How did those get in there. I've must've printed the wrong items

Here's what I found from bosch , 2 full sets for the same car

[johnro79]

One of them has a water pump, the other doesn't. Does that help you choose ?

How did those get in there. I've must've printed the wrong items

Here's what I found from bosch , 2 full sets for the same car

1987946974

1987946943

[dean warren]

Not sure how you got the above to show a quote from me though it isn’t anything i said…. Lol


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[johnro79]

Not sure how you got the above to show a quote from me though it isn’t anything i said…. Lol


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holly carp. sorry about that. gremlins-a-plenty today
between those 2 codes of mine, 1 was in stock , the other one wasn't . guess it made it easier

[VAG-Abound]

Well I love a good bit of sleuthing, so as far as I can see...

From onlinecarparts.co.uk:

1. 1 987 946 943 = 1 x Water Pump (Article №: 1 987 949 768) + 1 x Timing Belt Set (Article №: 1 987 946 582)
2. 1 987 946 974 = 1 x Water Pump (Article №: 1 987 949 768) + 1 x Timing Belt Set (Article №: 1 987 946 384)

So the timing belt sets are different.

Looking at Bosch PDF guides for each:

1. https://media.partauto.fr/download/1...0000COB200.pdf
2. https://media.partauto.fr/download/1...0000COTR00.pdf

...there are new bolts for a few things in the first listed. That PDF (click the EN link at top left it comes up in German) might be a handy read as well .

[johnro79]

Well I love a good bit of sleuthing, so as far as I can see...

From onlinecarparts.co.uk:

1. 1 987 946 943 = 1 x Water Pump (Article №: 1 987 949 768) + 1 x Timing Belt Set (Article №: 1 987 946 582)
2. 1 987 946 974 = 1 x Water Pump (Article №: 1 987 949 768) + 1 x Timing Belt Set (Article №: 1 987 946 384)

So the timing belt sets are different.

Looking at Bosch PDF guides for each:

1. https://media.partauto.fr/download/1...0000COB200.pdf
2. https://media.partauto.fr/download/1...0000COTR00.pdf

...there are new bolts for a few things in the first listed. That PDF (click the EN link at top left it comes up in German) might be a handy read as well .

thanks a lot
from those pdf's, it seems that one kit has more pulleys/rollers then the other. otherwise , the belt and water pump seem to be the same

now back to step 1 for me. i've touched all hoses before and after the thermostat and they seem to have the same temperature, hot
is there anything i could do to check by using VCDS to diagnose if water pump/flow is my issue there?

i know, by being overdue i have to replace both timing belt and coolant pump. just wanna check if there might be smtg else wrong/bad that i could replace while doing that expensive work.

as a secondary concern, it it worth doing a coolant flush/clean since all this is being done?
never done this before and don't know what to use, how to flush/clean it properly and how much new coolant to have on hand afterwards

thanks a lot for all your help