Alde Engine Pre Heat Pump Leaking (1 Viewer)

[dpsuk999]

I've just spent the day replacing the Alde engine pre heat pump which was leaking. On my last trip out I noticed the engine coolant had gone down quite a bit so topped it up and decided to check again a couple of weeks later and low and behold it was again down which indicated a leak somewhere but there was no coolant on the drive so decided to empty my lockers out.

For information this pump is used to circulate the engine coolant round a heat exchanger/engine which in turn is linked to the Alde heating so either when you have the Alde heating on (whilst on site) you can heat the engine coolant before starting your journey (I think it's for when you are for example skiing and want the engine warm before setting off) or alternatively when you are driving the hot engine coolant is circulated round the heat exchanger to heat the Alde heating and also the hot water so when you arrive on site your van is toasty and hot water on tap.

Anyway after emptying one of the lockers (where the pump is located it was wet and it's where I store the safari room bags which were all wet and stained red from the red coolant. When I inspected the pump closely i could see a small drip coming from where the body is screwed to the head!

So onto Alde website and I was amazed that the cost of a new pump was £240!! Anyway after some research I found that the pump is actually a Johnson pump so after googling I found a marine company up in Glasgow who had the very same pump (without the Alde badge) for £98.25 plus vat!

These guys were amazing and shipped very fast!

I also bought 2m length of heater hose, 16mm internal diameter to replace the hose.

Instead of having to drain all the engine coolant I used pipe clamps which are commonly used to clamp rubber pipes for fuel or coolant etc which saves a load of time.

Here you can see I clamped off the pipe which goes from the heat exchanger to the pump

I then went under the van and clamped the other coolant hose (ignore the join and jubilee clips as I took the picture after fitting the new pump)

which went to the other side of the pump and cut the hose. The only coolant lost was between the top clamp through the pipe/pump and the outlet on the pump to where I cut it under the van.

I then removed the old pump and pipes from the circuit

and attached new pipes to the new pump

I then reinserted them through the floors, one going above to the heat exchanger and the other through the van floor to re join the circuit

New pump in place

Interestingly the instructions for the pump had in BOLD that if the pump was installed horizontal then the outlet pipe should be pointing upwards to stop air locks and guess what.....the old pump was installed horizontally but with the outlet pipe going downwards!!

So as you can see from the new pump I made sure the outlet pipe was pointing upwards!

Anyway all tested and no leaks but apparently the pumps are very susceptible to failing if the engine coolant is not changed regularly.

Hope this info is of use to fellow funsters

 

[funflair]

Useful information indeed thank you, out of interest do you switch the pump on when you are travelling and want to run the Alde heating off the heat exchanger, I only ask as there seems to be a variety of opinions on the correct way to use the system.

Just for the record I only run the pump to warm the engine as ours works fine while driving without it running as it uses the engine water pump.

Martin

 

[tonyidle]

Where was it leaking? I notice it's a 'mag-drive' which means that the only connection between rotor & motor is magnetic. So no seals.

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[dpsuk999]

Useful information indeed thank you, out of interest do you switch the pump on when you are travelling and want to run the Alde heating off the heat exchanger, I only ask as there seems to be a variety of opinions on the correct way to use the system.

Just for the record I only run the pump to warm the engine as ours works fine while driving without it running as it uses the engine water pump.

Martin

Funnily you should ask that as I was always lead to believe you only run the pump when you want to warm the engine coolant from the Alde coolant but when I'd finished fitting the new pump I started the engine and let idle for 20 mins till the engine coolant was hot and touched the flow/return to the heat exchanger and was still cold so I turned the pump on and then the flow/return became hot. Not sure if that was because of an air lock so I'll test again tomorrow to see if they flow/return get hot from just running the engine and report back

 

[dpsuk999]

Where was it leaking? I notice it's a 'mag-drive' which means that the only connection between rotor & motor is magnetic. So no seals.

It was leaking from where the body and head are joined. There are 4 screws and was leaking from the bottom screw. When I googled it someone back in 2009 had had to replace 3 pumps and my van in 2008 so could have had a 'bad batch'

 

[Mr Mousy]

Great write-up. We don't have Alde heating - I wish we did just so I could follow your guidance and change the pump. Very informative.

@dpsuk999

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[dpsuk999]

Great write-up. We don't have Alde heating - I wish we did just so I could follow your guidance and change the pump. Very informative.

@dpsuk999

Thanks Alde heating is great, it was one of the main reasons I changed from my Burstner to the Dethleffs I have now

 

[funflair]

It was leaking from where the body and head are joined. There are 4 screws and was leaking from the bottom screw. When I googled it someone back in 2009 had had to replace 3 pumps and my van in 2008 so could have had a 'bad batch'

Just take the head off and clean it up and then back together with a bit of vaseline on the seal it will make a good spare (that you will never need).

Martin

 

[funflair]

Funnily you should ask that as I was always lead to believe you only run the pump when you want to warm the engine coolant from the Alde coolant but when I'd finished fitting the new pump I started the engine and let idle for 20 mins till the engine coolant was hot and touched the flow/return to the heat exchanger and was still cold so I turned the pump on and then the flow/return became hot. Not sure if that was because of an air lock so I'll test again tomorrow to see if they flow/return get hot from just running the engine and report back

As far as I am concerned you don't need the pump on for anything other than warming the engine block and ours certainly warms the van a treat (without the pump) when we are driving, but I do know that other people have different theories.

Martin

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[funflair]

Great write-up. We don't have Alde heating - I wish we did just so I could follow your guidance and change the pump. Very informative.

@dpsuk999

Mr Mousy you are getting very hands on these days, is Santa bringing you some new tools for Christmas.

Martin

 

[dpsuk999]

Just take the head off and clean it up and then back together with a bit of vaseline on the seal it will make a good spare (that you will never need).

Martin

Yes I'll strip it down and clean it up to keep as a spare but the biggest problem was where it was positioned in a locker. I barely managed to slide half my body in and reach my arms out to reach it. Because the rubber hoses had been on the pump for a few good years I couldn't manage to pull the hoses from the pump which lead me to buy replacement hoses and simply cut above in motorhome and below under the motorhome and fit new hoses on the new pump then thread them through the holes

 

[Mr Mousy]

Mr Mousy you are getting very hands on these days, is Santa bringing you some new tools for Christmas.

No new tools needed - I have lots in the shed - I am just reluctant to use them!

However I do like reading about other people's handywork and solutions to their moho problems.

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[funflair]

Yes I'll strip it down and clean it up to keep as a spare but the biggest problem was where it was positioned in a locker. I barely managed to slide half my body in and reach my arms out to reach it. Because the rubber hoses had been on the pump for a few good years I couldn't manage to pull the hoses from the pump which lead me to buy replacement hoses and simply cut above in motorhome and below under the motorhome and fit new hoses on the new pump then thread them through the holes

I think ours is under the bonnet someplace as I can hear it if I switch the pump on, hopefully I never need to change it.

Martin

 

[dpsuk999]

As far as I am concerned you don't need the pump on for anything other than warming the engine block and ours certainly warms the van a treat (without the pump) when we are driving, but I do know that other people have different theories.

Martin

I don't recall not having hot water or a warm hab area before so I'm sure it was an air lock. Luckily I have valve which includes an air release valve which I released some air on the engine coolant side of the heat exchanger (see pic below)

 

[funflair]

I don't recall not having hot water or a warm hab area before so I'm sure it was an air lock. Luckily I have valve which includes an air release valve which I released some air on the engine coolant side of the heat exchanger (see pic below)
View attachment 137880

You know its turned off there! just checking

Martin

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[dpsuk999]

You know its turned off there! just checking

Martin

Yes that was before I'd reassembled it all, I'll always remember the saying "the cock always follows the flow"

 

[bigtwin]

@dpsuk999 was your original, and the replacement, pump, a two speed pump?

Ian

 

[dpsuk999]

@dpsuk999 was your original, and the replacement, pump, a two speed pump?

Ian

Hi Ian, no both original and replacement are just one speed.

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[peterc10]

AFAIK the circulation pump on the my heat exchanger is on the engine coolant side. So it allows the engine coolant to be pumped through the heat exchanger to get pre-heated before the engine is started. The feed to the exchanger from the Alde heating is the normal Alde pump which circulates the heating fluid to all of the radiators.

So when using the engine heat to run the Alde you do not switch on the heat exchanger pump, because the engine coolant is being circulated already by the engine. All you do is switch the Alde heating on, but make sure it is not on gas. It then pumps the Alde fluid through the heat exchanger and picks up the heat from it.

So far we have found it works very well. Our previous motorhome had the Truma system, which we had no real complaints about, but we now prefer the Alde system, which just happened to be fitted to the motorhome we bought.

 

[dpsuk999]

AFAIK the circulation pump on the my heat exchanger is on the engine coolant side. So it allows the engine coolant to be pumped through the heat exchanger to get pre-heated before the engine is started. The feed to the exchanger from the Alde heating is the normal Alde pump which circulates the heating fluid to all of the radiators.

So when using the engine heat to run the Alde you do not switch on the heat exchanger pump, because the engine coolant is being circulated already by the engine. All you do is switch the Alde heating on, but make sure it is not on gas. It then pumps the Alde fluid through the heat exchanger and picks up the heat from it.

So far we have found it works very well. Our previous motorhome had the Truma system, which we had no real complaints about, but we now prefer the Alde system, which just happened to be fitted to the motorhome we bought.

That is correct, the circulation pump which I changed was on the engine coolant side and only needs to be in operation to circulate engine coolant via the heat exchanger when/if you ever want to warm your engine before setting off from a campsite via the hot Alde coolant passing through the heat exchanger (assuming you have had your Alde heating on)

 

[Adriaadventure]

AFAIK the circulation pump on the my heat exchanger is on the engine coolant side. So it allows the engine coolant to be pumped through the heat exchanger to get pre-heated before the engine is started. The feed to the exchanger from the Alde heating is the normal Alde pump which circulates the heating fluid to all of the radiators.

So when using the engine heat to run the Alde you do not switch on the heat exchanger pump, because the engine coolant is being circulated already by the engine. All you do is switch the Alde heating on, but make sure it is not on gas. It then pumps the Alde fluid through the heat exchanger and picks up the heat from it.

So far we have found it works very well. Our previous motorhome had the Truma system, which we had no real complaints about, but we now prefer the Alde system, which just happened to be fitted to the motorhome we bought.

Due to a problem with the pipes from the heat exchanger to the engine I needed to trace rubber hoses as they warmed up to determine which was the flow and which one was the return. It turns out that the pre-heat pump ( when you run it ) circulates the glycol in the opposite direction to the direction of flow when the engine is running. Makes sense to warm the parts of the engine that would get hot first when its started !.

The only time I have used this is when on-site all packed up and ready to go, open screen blinds and the windscreen is all steamed up.
With the heating having been on ( gas or EHU ) the glycol is already hot in the heating system and with the pre-heat pump switched on that heat is transferred very quickly to the engine... And as the pipes that go to the engine are simply Tee'd to the Cab heater matrix pipes under the bonnet the glycol splits 2 ways half to engine and half to the cab heater.
Ignition switch on, Blower fan on full. Result... windscreen cleared in a minute or two and off you go. Not forgetting to switch off the pre-heat pump, which is unlikely as this little pump is noisier than the engine.

S0oooo what was wrong with the Alde pipes to the engine ?
Well with just 800 miles on the clock I was laid under the motorhome admiring the view of the underside of the shiny new engine and gearbox ( as you do ) and noticed that grease had been sprayed everywhere around the nearside driveshaft inner CV joint. Examining the CV boot I was certain the grease had come out of it and booked the MH in at my dealer near Newark.
CV boot duly replaced ( a sharp object had apparently damaged the rubber boot causing a cut , okay.., and was replaced under warranty.
A week or so later I decided to take a look at the sterling work carried out ( not that I don't trust work carried out by Brownhills ), MH front up on ramps, slithered under MH CV boot still wet with grease ?.
Was it that it hadn't been cleaned after replacing, perhaps they now come new coated in a preservative oil/grease ?
To examine it better I jacked up the nearside front wheel to give a better view of the driveshaft and saw a rubber hose, partly covered with a silver coated thermal spongy jacket, hanging down under its own unsecured weight riding on the new CV boot as it would be rotating when travelling.
It became obvious the grease soaked spongy cover had transferred onto the new CV boot.
Further examination showed the old CV boot had not only failed due to rubbing on the Alde pipe but also the rubber pipe had a curved groove in it which made the pipe thin in that area but not yet so deep to allow loss of engine cooling fluid, Can't bear to think about that possibility.
Having secured the pipe up to the bulkhead to clear the CV joint. It was back to the dealer and the pipe ( that was about 400 - 500mm too long, hence hanging down ) was replaced.
So how did the technician remove the wheel, driveshaft etc to change the CV boot apparently without noticing the Alde pipe riding on to of it ??
Some mysteries will never be fully understood.

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[Scotch mist]

I’m actually not surprised, I’ve had 3 brand new MH’S in the last 2 years & I’m
shocked at the way the hot/cold water & alde pipes are just lying on surfaces with no support, often chafing on things , it was only a matter of time till they ruptured
I've spent 3 days making them safe by supporting & insulating them

 

[A S R]

I just had my heat exchanger pump replaced. I had a genuine Alde one put on at the frightening £240 price tag. I wish I’d known about that other one! Hey ho.

 

[Steve and Denise]

As far as I am concerned you don't need the pump on for anything other than warming the engine block and ours certainly warms the van a treat (without the pump) when we are driving, but I do know that other people have different theories.

Martin

We’ve had 4 vans with Alde heating all with engine pre heat pumps but never used them but never been skiing.
The vans have all heated up from the small heat exchanger just fine, I think if I had a engine circulation pump fail it would be a quick bypass as I have never needed it in ten years.

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[EzeeRider]

My van is fitted with just the heat exchanger. It does not have the pump to heat the engine. One less thing to go wrong unless you absolutely need it. Nevertheless, an interesting article .
ezee

 

[Adriaadventure]

We’ve had 4 vans with Alde heating all with engine pre heat pumps but never used them but never been skiing.
The vans have all heated up from the small heat exchanger just fine, I think if I had a engine circulation pump fail it would be a quick bypass as I have never needed it in ten years.

Think I agree it is a liability for just a little gain.
I have added a suitable heat resistant plastic barbed pipe joiner/connector to the MH parts kit so I am ready to bypass it if and when it leaks. Its just limiting the loss of engine coolant when removing the pump that could be a problem. still, It might never happen.
I noticed there is an air bleed and a shut off valve next to the heat exchanger 3 feet from the pump so that's not a problem with that pipe but coolant will $iss out of the other pipe connected to the pump.

 

[funflair]

This is the first case of one of these pumps leaking that I know of so I wouldn't be inclined to panic overly, I imagine it would be quite simple to take the head off and re-seal it so personally I won't be carrying a spare

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[Steve and Denise]

Think I agree it is a liability for just a little gain.
I have added a suitable heat resistant plastic barbed pipe joiner/connector to the MH parts kit so I am ready to bypass it if and when it leaks. Its just limiting the loss of engine coolant when removing the pump that could be a problem. still, It might never happen.
I noticed there is an air bleed and a shut off valve next to the heat exchanger 3 feet from the pump so that's not a problem with that pipe but coolant will $iss out of the other pipe connected to the pump.

Two small vice grips very useful tools and only light

 

[Steve and Denise]

This is the first case of one of these pumps leaking that I know of so I wouldn't be inclined to panic overly, I imagine it would be quite simple to take the head off and re-seal it so personally I won't be carrying a spare

I’m not panicking either Martin our new van is only 2 years old