PRM 150 Oil Change

[Saffa]

Evening

 

 

Right so we are off on a 4 week trip at the end of the week and I thought about changing the oil in the gearbox. ( I have no idea how many hours its done and I've added about 60 )

 

So is it just a matter of removing the sump screw and draining the old oil. Then filling up with 1.5L of 15W40 Mobil Multigrade. Run while tied up for 5 mins then check oil level.

 

Do I need to be checking anything else?

 

Something else. When changing the oil filter on the engine do I put some new oil in it?

 

Thank you

 

 

 

 

[RLWP]

You have the gearbox sequence right

 

The engine question - it depends. Some engines you can do that on, on some others the oil will spill out when you fit the filter. If you want, you can run the engine on the starter with the stop control pulled/lever across/whatever until the oil pressure light goes out. This will fill the filter and the rest of the system at low engine speed

 

Or just fit the filter

 

Richard

[Saffa]

You have the gearbox sequence right

 

The engine question - it depends. Some engines you can do that on, on some others the oil will spill out when you fit the filter. If you want, you can run the engine on the starter with the stop control pulled/lever across/whatever until the oil pressure light goes out. This will fill the filter and the rest of the system at low engine speed

 

Or just fit the filter

 

Richard

 

Thank you Richard

 

My filter is fitted horizontally so I would only be able to fill it about 1/3. Once I start I would expect to see the Oil light on.

 

How long is too long for this light to be on for?

[RLWP]

 

Thank you Richard

 

My filter is fitted horizontally so I would only be able to fill it about 1/3. Once I start I would expect to see the Oil light on.

 

How long is too long for this light to be on for?

 

Heck - how long is a piece of string! How fast will you run the engine? A few seconds would be right, but a second is a long time when you are watching for a light to go out to reassure you that you haven't wrecked your precious engine (you won't have by the way).

 

Your filter has a series of holes around the inside edge of the seal, so you won't even get it a third full. On the other hand, it will be nearly empty when you take it off so less mess

 

Richard

[IDS]

If the PRM sump plug is very inaccessible (like mine), you can also suck the oil out of the filler hole with a suitable hand pump and a bit of plastic pipe.

[Nickhlx]

I have always wondered this and even ventured to running an engine for a few seconds with "all" the oil out and filter off to "blow through any old oil" before re-filling... I have never had any adverse effect though.

 

Whilst some say warm the engine up to drain the oil, I think this stemmed from when changing car engine oil where the sump plug would be removed and the oil would gush out faster, taking any sediment with it, as the oil would be more mobile when warm / hot. When removing the oil from e.g. a Beta 43, with manual hand pump to suck it out of the sump, this effect is not present..

 

My current thoughts are to start the cold engine to ensure oil is pressurised up in every bearing, but for only maybe 15 seconds, stop it and wait a few minutes and pump out what you can, (oil will be cold and more viscous) remove the filter, start again (!) for 3 to 5 seconds max, at no faster than idle, switch off, and wait maybe 10+ minutes for any oil to drain down to the sump and pump out well, then replace oil filter with as much oil as you can reasonably get in, replace drain plug if appropriate, refill and start again, at idle, to circulate the fresh oil until the pressure comes up. Then when normal cold pressure has been present for a minute or two can you safely raise the revs to fast idle and higher as the engine warms up.

 

My thought with draining the oil when cold is that, being cold, the oil is more viscous and will not drain from the bearings so readily, which in turn gives a few seconds more time in the bearings when re-starting. Of course the "interim start" with an empty engine to blow through the oilways is entirely up to the owner of the engine, and will possibly only displace another half pint of old oil.

 

When you see the "YouTube" videos of people wantingly blowing up car engines by draining the oil out and then starting the engine and revving at high speed ( Cringes in horror), and even then the engines are lasting many minutes, I have little worries about running an engine at idle for a few seconds...

 

Nick

Edited September 14, 2015 by Nickhlx

[Tonka]

If the PRM sump plug is very inaccessible (like mine), you can also suck the oil out of the filler hole with a suitable hand pump and a bit of plastic pipe.

 

If you do this how do you check for metal particles that will be attached to the magnet on the sump plug

[blackrose]

I don't really understand the need to fill a new oil filter prior fitting? The main thing to remember is to smear a bit of oil around the rubber seal.

 

Is the correct API CC oil spec important for the gearbox or just the engine?

[nicknorman]

I have always wondered this and even ventured to running an engine for a few seconds with "all" the oil out and filter off to "blow through any old oil" before re-filling... I have never had any adverse effect though.

 

Whilst some say warm the engine up to drain the oil, I think this stemmed from when changing car engine oil where the sump plug would be removed and the oil would gush out faster, taking any sediment with it, as the oil would be more mobile when warm / hot. When removing the oil from e.g. a Beta 43, with manual hand pump to suck it out of the sump, this effect is not present..

 

My current thoughts are to start the cold engine to ensure oil is pressurised up in every bearing, but for only maybe 15 seconds, stop it and wait a few minutes and pump out what you can, (oil will be cold and more viscous) remove the filter, start again (!) for 3 to 5 seconds max, at no faster than idle, switch off, and wait maybe 10+ minutes for any oil to drain down to the sump and pump out well, then replace oil filter with as much oil as you can reasonably get in, replace drain plug if appropriate, refill and start again, at idle, to circulate the fresh oil until the pressure comes up. Then when normal cold pressure has been present for a minute or two can you safely raise the revs to fast idle and higher as the engine warms up.

 

My thought with draining the oil when cold is that, being cold, the oil is more viscous and will not drain from the bearings so readily, which in turn gives a few seconds more time in the bearings when re-starting. Of course the "interim start" with an empty engine to blow through the oilways is entirely up to the owner of the engine, and will possibly only displace another half pint of old oil.

 

Nick

I think you are making it a bit complicated! And demonstrating the conflict between wanting to get all the old oil out vs wanting to keep some oil in (the bearings) for the restart.

 

Personally I always change the oil when it's hot. If you run the engine briefly from cold, a lot of cold thick oil gets onto all the internal surfaces within the engine and may then take a long time to drain out - and will also eventually drain out of the bearings so back to square one. So I would say the result is the same, the time taken to achieve it is much longer with cold oil. Life is too short for that!

 

So I would say drain with the engine hot, refill (smear oil onto the filter seal, but don't attempt to fill the filter) and start the engine at idle. The oil light will go out within 5 seconds or so.

 

Regarding the gearbox I tend to get most of the oil out with a pump through the dipstick hole, but always remove the sump plug to get the last 1/4 litre out. It's less messy to get the bulk of it out via a pump.

[Bee]

If you have to suck the oil out it is hard work if its cold, just run the engine till its warm, drain the old stuff out , put a new filter on, stick new oil in and start the thing on tickover, don't rev it to get the oil light to go out quicker, 3 or 4 seconds will do it , check the levels, wipe up the mess, put spanners away, make tea.

[bizzard]

If the boat is careened right over to the filters side you'd be able to fit a horizontal filter full of oil without spilling.

[blackrose]

I've always run the engine in gear to warm the gearbox oil up prior to draining it on my prm150. As it's a separate unit with separate oil I thought this was necessary?

[Chewbacka]

When refilling, don't forget that the gear box has an oil cooler and depending on the pipe work may need a bit more oil then the prm spec sheet when you refill. I also warm up the gear box before sucking the oil out the dip stick/filler hole as I hope it helps the oil cooler to empty. The first time I used this method, not much oil came out, and I found you have to wiggle the suction pipe around to get it to the bottom of the gear box. After refilling check again after a few mins running as the oil cooler may have had air in it. I am making this sound much harder than it is.

[gazza]

I've always run the engine in gear to warm the gearbox oil up prior to draining it on my prm150. As it's a separate unit with separate oil I thought this was necessary?

Absolutely. its crazy to do anything but change oil while its hot.

 

I've never heard anyone suggesting oil should be changed cold.

 

If the filter is mounted such that it can't be preoiled then do as Richard suggests and pull the stop/disable the stop solenoid and spin over until light goes out/pressure registers on the gauge.

 

An engine will spin at around 200rpm on the starter, there will be plenty of oil about from the last run to protect it - anyone who had stripped an engine will know the oily bits are, well, still oily!

 

As for wanging the engine over to get the last little bit of old oil out? That too is a new one on me and totally OTT.

 

Carry on as you are Mike

[Machpoint005]

I get hold of a 2-litre rectangular section plastic bottle (eg the thing screen wash fluid comes in) and cut a small hole near the top of one flat side. The whole thing slides under the gearbox with the hole lined up under the sump plug*. Undo plug, drain oil, lift out bottle without spilling any.

 

 

*ETA -- with the top screwed back on!

Edited September 15, 2015 by Machpoint005

[Sea Dog]

What matchpoint said - but a milk bottle does it for me.

[blackrose]

Absolutely. its crazy to do anything but change oil while its hot.

 

I've never heard anyone suggesting oil should be changed cold.

 

If the filter is mounted such that it can't be preoiled...

My gearbox oil doesn't have a filter - at least I don't think so?

[gazza]

My gearbox oil doesn't have a filter - at least I don't think so?

Sorry, I was just rambling in the general spirit of the thread! I wasn't specifically referring to your 'box.

 

As you say, hot oil, suck it out on to the next task - hopefully a brew as someone else mentioned in another thread on oil changes

 

It amazes me how complicated sucking/draining oil can become...

Edited September 15, 2015 by gazza

[nicknorman]

I've always run the engine in gear to warm the gearbox oil up prior to draining it on my prm150. As it's a separate unit with separate oil I thought this was necessary?

Well first of course, you shouldn't run the engine in gear whilst tied up, in a canal (yes I know you are moored in a river at the moment!).

 

But it is not necessary to run the engine in gear in most cases, since there is an engine coolant / gearbox oil heat exchanger in PRM150 boxes and the like, thus the gearboxoil (circulating even in neutral) is warmed by the hot engine coolant. Even without a heat exchanger there is quite a lot of heat generated just by the churning effect - gears meshing in oil, even with no load being transmitted.

[RLWP]

Well first of course, you shouldn't run the engine in gear whilst tied up, in a canal (yes I know you are moored in a river at the moment!).

But it is not necessary to run the engine in gear in most cases, since there is an engine coolant / gearbox oil heat exchanger in PRM150 boxes and the like, thus the gearboxoil (circulating even in neutral) is warmed by the hot engine coolant. Even without a heat exchanger there is quite a lot of heat generated just by the churning effect - gears meshing in oil, even with no load being transmitted.

You might like to check that, Nick. The cooler usually sits in the suction pipe to the engine, and the water from a skin tank is surprisingly cold

 

Richard

[gazza]

Well first of course, you shouldn't run the engine in gear whilst tied up, in a canal (yes I know you are moored in a river at the moment!).

 

But it is not necessary to run the engine in gear in most cases, since there is an engine coolant / gearbox oil heat exchanger in PRM150 boxes and the like, thus the gearboxoil (circulating even in neutral) is warmed by the hot engine coolant. Even without a heat exchanger there is quite a lot of heat generated just by the churning effect - gears meshing in oil, even with no load being transmitted.

Yeah but, yeah but!!!!

 

Our Borg Warner velvet drive has an oil cooler, cooled by raw water....

Running it in neutral would take forever to warm the oil thru.

 

The best bet for me is a chug to the Kings Head, Wadenhoe (about 30 mins) couple of pints, zip back to the club then slurp the oil out of engine and box PDQ. once slurping of oil is finished its time to replenish with fresh oil and cider (the beer is for me but you probably guessed that )

[bizzard]

You might like to check that, Nick. The cooler usually sits in the suction pipe to the engine, and the water from a skin tank is surprisingly cold

 

Richard

Unless your belting along with an undersize skin tank or a thrombosis has occurred in the cooling circuit.

[nicknorman]

You might like to check that, Nick. The cooler usually sits in the suction pipe to the engine, and the water from a skin tank is surprisingly cold

Richard

 

Yeah but, yeah but!!!!

Our Borg Warner velvet drive has an oil cooler, cooled by raw water....

Running it in neutral would take forever to warm the oil thru.

The best bet for me is a chug to the Kings Head, Wadenhoe (about 30 mins) couple of pints, zip back to the club then slurp the oil out of engine and box PDQ. once slurping of oil is finished its time to replenish with fresh oil and cider (the beer is for me but you probably guessed that )

Ok, so I was wrong then! But I am not sure that running the engine at idle in gear would make much difference? I always change the gearbox oil at the end of a day's cruising when it's nice and hot. Edited September 15, 2015 by nicknorman

[RLWP]

Ok, so I was wrong then! But I am not sure that running the engine at idle in gear would make much difference? I always change the gearbox oil at the end of a day's cruising when it's nice and hot.

An excellent plan.

 

Richard

 

MORE: I suspect that you get more heat from the pump and relief valve than from the churn of the gears

Edited September 15, 2015 by RLWP

[bizzard]

If you wrap some wide cellotape-duct tape around the open end of a horizontal oil filter, but only sticking half its width to it leaving the other half flopping about and fill the filter with oil and screw it on ever so, ever so fast, not much oil will spill out as the tape will act as a crude seal up against the block. But be careful not to trap any of the tape between the filters sealing surfaces. Peal off tape afterwards, and relax.