Volvo Power Steering Oil Cooler Maintenance

[Scubadoo]

Checked visually my raw water intake power steering oil cooler (AD31/KAD32 - DPE), a couple of questions…is this completely made of copper? The reason I ask, some black paint has flaked off and thinking it is just cosmetic as there are no signs of corrosion. Is there anything I should look out for in terms of maintenance? Also I noticed it has a drain cock which looks okay i.e. no corrosion visible, I have never opened it and not sure why you would need to, should it be replaced or leave well alone, what material is it copper?

When the boat is lifted, considering whether to remove and paint or paint in situ. If removed, is it fairly easy job to do? Is it a case of just disconnecting the two oil pipes and keep them suspended to prevent oil loss and simply reconnect, and what is the best way to purge air, just move the steering lock to lock? Interested what others do with their oil cooler in terms of maintenance. Thanks.

 

[BruceK]

is this completely made of copper?

A copper or brass alloy yes, but it is rather soft so I'd say copper alloy

I noticed it has a drain cock which looks okay i.e. no corrosion visible, I have never opened it and not sure why you would need to, should it be replaced or leave well alone, what material is it copper?

I'd seriously recommend you remove and inspect it. Mine looked ok until I tried to undo it and it had the consistency of baked clay. I ordered the brass drain plug and a new cooler for expediency. The plug was 10 quid but the new cooler no longer had that fitting. It's so much easier to drain by loosening the raw water pump pipe and dropping it into the bilge. (boat out of the water of course)

remove and paint or paint in situ. If removed, is it fairly easy job to do

Painting in situ would be a half job, removing is easy enough, but the pipe holding bracket that bolts down and secures the pipe into position just before the cooler.... well that bolt is liable to rust up. Be prepared to buy a new bracket or bolt and in a worst case scenario replace that segment of pipe too. You'll need access to the transom shield to complete this.

what is the best way to purge air, just move the steering lock to lock?

With the engine running that is the only way. Monitor the reservoir. It will fill and drop. readings are taken with steering neutral / dead ahead.

what others do with their oil cooler in terms of maintenance.

Apart from the brass plug I have found them maintenance free. I opened mine up to see if there was any growth in them or the pipes. Mussels like enclosed spaces. However it's obviously too dark and inhospitable there. Clean as a whistle. It seems the nasties and calcium buildup only happens once things hit the various heat exchangers.

However knowing it is a massive single point of failure that is absolutely guaranteed to sink your boat if it fails it is worth checking regularly that it is in good and sound condition.

 

[Scubadoo]

Thank you Bruce, very helpful guide. Where did you purchase the drain plug and new cooler? I like the idea of no drain plug on the new cooler but depends how much it costs. I guess trying to remove the drain plug it might shear off at the thread and hence probably the cooler would then need to be replaced.

When replacing the drain plug, any recommendations on sealing thread e.g. ptfe tape or similar or nothing at all.

Again thanks.

 

[BruceK]

I purchased mine from Marine engine parts, boat engine parts

 

[BruceK]

When replacing the drain plug, any recommendations on sealing thread e.g. ptfe tape or similar or nothing at all.

I dont tend to use anything. IIRC the fitting and thread is cone shaped and self seals. Stuffing gunk in there wont help much.

I replaced my cooler simply as a matter of course when I noticed the train tap had dezinced. As above. It's a single source of catastrophic failure and why mess about when the entire boat and it's recovery is at stake. Plus I have a habit of just replacing parts much to my peer's mirth. As if boating wasn't expensive enough

 

[Scubadoo]

I dont tend to use anything. IIRC the fitting and thread is cone shaped and self seals. Stuffing gunk in there wont help much.

I replaced my cooler simply as a matter of course when I noticed the train tap had dezinced. As above. It's a single source of catastrophic failure and why mess about when the entire boat and it's recovery is at stake. Plus I have a habit of just replacing parts much to my peer's mirth. As if boating wasn't expensive enough

Thanks Bruce, I tend to agree, replace the cooler would seem a wise move instead of messing around with the drain plug. Trouble is, I could replace the drain tap only to find it weeping and would mean another lift out to sort it.

 

[BruceK]

Well, it would be prudent to lift the boat out but there are ways to limit the influx of water to manageable amounts if that were the case.

BTW the one thing I didn't mention. When you remove the hydraulic oil hoses. You will need to cut the ends that have been compressed by the jubilee clip off and reseat with a new jubilee clip to fresh rubber. They will drip leak otherwise as the rubber doesn't spring back once it's been crushed by the jubilee. There is plenty slack so it's no bother

 

[joae]

I have the same cooler and my drain was also like baked clay as BruceK mentions. I guess this is what they call selective leaching ;-). I soldered on a new fitting and fitted just a plug and pressure tested the cooler. If this falls of you could sink the boat if left unattended so I think this is quite important to fix.

 

[Scubadoo]

Volvopaul/Spannerman, with the many 100s of boats you work on, curious what you have found in the past with power steering coolers. What do you guys do with general preventive maintenance and have you experienced any leaking. Do you replace drain cocks and if so what has been your experience.