Have I got a leak?

[alt]

Spotted this today on the manifold of my KAD300.

Presume that's a leak from the coolant sensor? (Located at the back of the manifold, under the Turbo)

Temp seems fine so presume the sensor is fine... but wondering if I should change it while the manifold is out (changing manifold gaskets). On marinepartseurope it just shots a stop cock there?!

OR, should I just change the copper washer? (presume it's a copper washer... looks like one!)

 

[petem]

Spotted this today on the manifold of my KAD300.

Presume that's a leak from the coolant sensor? (Located at the back of the manifold, under the Turbo)

Temp seems fine so presume the sensor is fine... but wondering if I should change it while the manifold is out (changing manifold gaskets). On marinepartseurope it just shots a stop cock there?!

OR, should I just change the copper washer? (presume it's a copper washer... looks like one!)

The washers are listed on Marine Parts...

Volvo Penta Exploded view / schematic Electrical System: B KAD44P-C, KAD300-A - MarinePartsEurope.com

Seema sensible to me to remove, repaint and refit the sensor.

 

[BruceK]

tbh you can never be sure if the new replacement washer has been annealed or still work hardenned from the stamping process so it's good practice to re-anneal them anyway. If yours has not deformed from over enthusiastic tightenning then it may well have been put in without annealing it from the go. I'd simply re-anneal in that case by heating to a dull cherry red (done in low light) while suspended from a wire and not pliers ( heat sink) for a minute or two then drop it into water to descale it. Check all the mating surfaces are clean and even and re use. If you're buying a new washer you should be doing this anyway

 

[alt]

So, loosened earlier and it loosened a bit too easy, so I do suspect there was a leak there. Took BruceK advise (also advised by a local guy on-site), cleaned everything up and re-seated (nice and tight this time).

I cleaned up the nut to try and get a part no. For anyone who may ever need to replace this sensor, the OE seems to be: VDO 805/38/1 (Max. 150 degree C)