[Blast Away]

All the machines I have had and still have and I have never replaced an unloader valve!!

Rob

I find that hard to believe Rob.

[Roland S]

i've done a bit of research and also spoken to the tech dept who blend this oil, and for the pump - at least in my case (interpump vv965) - you need a detergent free sae 30 oil. apparently the detergent free bit is quite important as the detergent increases wear on the valves. this is what i bought if anyone is interested:

"Smith & Allan Classic Vintage Select SAE 30 Detergent Free Motor Oil 1 ltr"

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=370567523163

[Matt Gibson]

I just bought interpumps own brand oil.

[BDCS]

And exactly how does the oil increase wear on the valves an an Interpump vv965  Are you adding it to the water supply 
You spoke to the technical dept and they told you that 

[Roland S]

I know nothing about pumps I must have got confused. I spoke to the tech guy who makes that oil not inter pump. That's the right oil anyway and cheaper than I could find elsewhere.

[BDCS]

The oil on the pump is a simple crankcase and because it suffers very little heat range then a mono grade will suffice. The anti foaming property is more important in this case. There is an air gap and tell tale between the crankcase and the pump head so the oil will never ever contact the valves unless something goes very wrong - the valves sit in the water gallery. Any light gear oil will do as would a 30 grade hydraulic oil in this particular case. The person you spoke to was obviously talking about engine oil and probably still thinks its 1956.
  Anyway you go with what you believe to be correct but do everyone around you a favour and use the trigger corectly - a good unloader is about £40 and will outlast the warranty. I found 6 unloaders on my bench last week and only one had been stripped and hence failed - I use Pulsar 3's.

[Kenny83]

I just use engine oil 10 40 in my machines, the Cat pump and yanmar diesel engine, before that I used it in my honda diesel and cat pump and before that I used it in my petrol.... never ever had a problem with the runnings if the machine...
I also have never had a problem with my unloaders, although I have come across alot of machine with failed unloaders. I reckon a simlple leaking gun/hose/etc would be the biggest cause of unloader failure, or maybe people who do alot of gum removal and valeters etc... people who are on and off the trigger alot

[BDCS]

I thought Smiff & allen made the guns in cowboy films 
Re oil "owt's better than nowt"
I stand around talking and drinking tea and can't always be bothered to shut the machine down if the drive is on a slope and being too old walk any further than I need to - I change the oils valves and unloader once a year or when the hour meter says do it, for the money its cheaper than loosing an afternoon's work and wasted travel and finding a slot to return

[Kenny83]

Ha ha, A service guy actually said that to me once, when I asked him what oil best to put in, he replied with 'any oils better than no oil' 

[BDCS]

When I was at the pit we only had one gear oil, one hydraulic oil and one emulsifying oil in common use. Good quality oil will do many appications and not just what you imagine it would do. Obviously some oils are developed for specific applications but a pressure washer pump is quite rustic. You'll never beat Castrol R for smell 

[chris scott]

Aaah  cassie "R". That takes me back!

[Roland S]

The oil on the pump is a simple crankcase and because it suffers very little heat range then a mono grade will suffice. The anti foaming property is more important in this case. There is an air gap and tell tale between the crankcase and the pump head so the oil will never ever contact the valves unless something goes very wrong - the valves sit in the water gallery. Any light gear oil will do as would a 30 grade hydraulic oil in this particular case. The person you spoke to was obviously talking about engine oil and probably still thinks its 1956.
  Anyway you go with what you believe to be correct but do everyone around you a favour and use the trigger corectly - a good unloader is about £40 and will outlast the warranty. I found 6 unloaders on my bench last week and only one had been stripped and hence failed - I use Pulsar 3's.

Thanks for the info. Yeah I'll use the unloader in the future.

[Donnie Nicolson]

I use 15/40 semi synth in both engines and pump , always have my 3 gx390 are 8 years old now, I run 2 interpumps and 1 cat pump, never replaced an unloader either, I bought 1 as a spare when I set up the biz and its still in my workshop unused, I do service very regular though, every 3 months as a matter of fact ive not replaced the valves in the interpumps either have done in the cat pump though