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What have you done to your Elgrand today?

As many of you will know I have 2 E51's, usually use my black one but the white one has had most of the towing (my large caravan) duty.

The white one has recently (before my last holiday in August towing the caravan) had a new rad, the old one seemed to be leaking from around the bottom.

On the way to Cornwall the temp gauge rose a bit so I pulled into services, allowed the engine to cool and checked coolant, it was down a bit in the rad, topped it up and continued on the journey. Had to do the same 50 miles later. The coolant loss seems to be getting worse and it seems to be caused by pressure in the coolant circuit causing coolant to be pushed into the expansion tank, there seems to be quite a lot of pressure in the system even when OBD reports coolant temp of only (say) 87degrees.

Generally in situations like this the problem turns out to be something like a head gasket allowing cylinder pressure to pressurise the cooling system but I'm hoping that isn't the case. Other things that can cause the same symptoms are if there's a leak on the cooling system it can allow air to be sucked in to the cooling system causing the over-pressure (a bit anti-intuitive but this can and does happen), or if the water pump isn't circulating coolant very well there can be localised hotspots that see coolant temp (reading etc) normal but pressure from boiling at the hotspots.

I intend on cold pressure testing the system to see if I can find any leaks that might also allow air to enter.
Then maybe have a look (and/or change) the water pump.
Then maybe slightly loosen then re-tighten head bolts.

It can sit there idling all day and not over-pressurise or lose any water, or I can drive it steady and it's the same. But if I start giving it a bit of stick it over-pressurises and loses coolant. When we set off for Cornwall in August it seemed fine for the first 200 miles before this started. I know it isn't mixture (lean etc) related. Hoping there isn't some kind of slight leak (that could only get much worse) on a head gasket etc.

Anyone else have any thoughts?

@BMR I've just been looking at water pumps and thermostats on your website ;)
 
Last edited:
Lpgc said:
As many of you will know I have 2 E51's, usually use my black one but the white one has had most of the towing (my large caravan) duty.

The white one has recently (before my last holiday in August towing the caravan) had a new rad, the old one seemed to be leaking from around the bottom.

On the way to Cornwall the temp gauge rose a bit so I pulled into services, allowed the engine to cool and checked coolant, it was down a bit in the rad, topped it up and continued on the journey. Had to do the same 50 miles later. The coolant loss seems to be getting worse and it seems to be caused by pressure in the coolant circuit causing coolant to be pushed into the expansion tank, there seems to be quite a lot of pressure in the system even when OBD reports coolant temp of only (say) 87degrees.

Generally in situations like this the problem turns out to be something like a head gasket allowing cylinder pressure to pressurise the cooling system but I'm hoping that isn't the case. Other things that can cause the same symptoms are if there's a leak on the cooling system it can allow air to be sucked in to the cooling system causing the over-pressure (a bit anti-intuitive but this can and does happen), or if the water pump isn't circulating coolant very well there can be localised hotspots that see coolant temp (reading etc) normal but pressure from boiling at the hotspots.

I intend on cold pressure testing the system to see if I can find any leaks that might also allow air to enter.
Then maybe have a look (and/or change) the water pump.
Then maybe slightly loosen then re-tighten head bolts.

Anyone else have any thoughts?

@BMR I've just been looking at water pumps and thermostats on your website ;)
Click to expand...
hope it's not HGF mate :(
 
cjholding said:
Given the complexity of the bleeding procedure I'd be looking for an air lock in the system.
Click to expand...
I'd side with Charles, given that the rad was swapped out does point to a potential air-lock, can't fault his logic.
But I'm not a car mechanic....
 
I'm used to bleeding the cooling systems on just about every vehicle you can imagine though... And regard the official E51 bleeding procedure as something that could cause problems in itself (the bit about hold rpm at 3000 for 10mins...), not something I would want to follow because better ways are possible. For a start if you want to get air out of a system you need to leave an opening for the air to escape = leave the rad cap off ;-) No airlocks I'm sure.

Edit - I'd say that as a mechanic you learn to trust your own judgement regards bleeding, and (importantly) you get to know what vehicles have bleed screws etc that are best not touched.. Bit different on an Elgrand because they don't have bleed screws, but if you follow the bleed procedure on something like a BMW with straight 6 engine you're asking for problems, more likely to damage the cooling system by adjusting old and temperamental/brittle bleed screws. Elgrand cooling systems bleed up easily, the similar VQ35 in a Skyline is more difficult to bleed. A BMW V8 bleeds up easily, a BMW straight 6 is more difficult. But I'd never follow the part of a procedure that says run the engine for 10 minutes at 3000rpm with the rad cap still on! If it's bled before 10 minutes there's no need for the 10 minutes, if it isn't bled then running it for 10mins at 3000rpm would likely cause an engine problem. Better to let the air out, top it up and test by driving well before 10mins.
 
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Deanhempshall said:
Looking into LPG....Mrs starts her new job shortly which means we get weekends back, in turn more camping/travelling so might be worth it. I've shot @Lpgc a message so I can weigh up the cost Vs payback time.
Click to expand...
Where did you send me the message?
 
Deanhempshall said:
Looking into LPG....Mrs starts her new job shortly which means we get weekends back, in turn more camping/travelling so might be worth it. I've shot @Lpgc a message so I can weigh up the cost Vs payback time
Click to expand...
You'll probably know this but I'll say it anyway. Payback time is is variable and depends upon
  • conversion cost
  • price difference between LPG and petrol
  • mileage
  • drivers driving style
  • journey types
When I did my calculations the fuel difference was about 80p a litre and an estimate of 6000 miles a year. I estimated it would take me 2 years which nicely coincided with the conversion warranty if the installer does the first annual service check.
 
Magnu said:
You'll probably know this but I'll say it anyway. Payback time is is variable and depends upon
  • conversion cost
  • price difference between LPG and petrol
  • mileage
  • drivers driving style
  • journey types
When I did my calculations the fuel difference was about 80p a litre and an estimate of 6000 miles a year. I estimated it would take me 2 years which nicely coincided with the conversion warranty if the installer does the first annual service check.
Click to expand...

I'd also add
  • tank capacity
  • how soon the system switches from petrol to LPG during engine warmup
  • whether or not any 'petrol addition' or 'switch back to petrol at high engine loads' is used,
  • equal fuelling on all cylinders
  • correct mixture swing during transient conditions such as adjusting the throttle
  • correct (suitably rich but not as rich as petrol) mixture during high load open loop fuelling conditions
  • correct extra injection filtering
  • having to visit the installer
Tank capacity because if you run out of LPG you will be running on petrol (with obvious effect on fuel costs for that journey). I could use what would be the entire contents of an LPG tank fitted at some other installers (so that tank would be empty) and still have enough gas in my bigger tank to have a 120 mile round trip drive to the coast and back without running out of LPG.

How soon the system switches from petrol to LPG because every second that the engine runs on petrol doesn't save any money, so you want the engine to switch to LPG relatively soon during engine warm-up.

Some systems are set up to add petrol at some (from medium to high or even during all) engine loads and/or switch fully back to petrol at high engine loads. Again if petrol is used as part (or 100% in some conditions) of the fuelling then it won't save as much money (and the LPG switch may not show the addition of petrol or full switch back to petrol).

If LPG injectors are not equally matched (even with same make/model injectors on all cylinders) then some cylinders will get slightly richer mixture while other cylinders get slightly leaner mixture. The average mixture reflected by the lambda probe readings (and fuel trims etc) wouldn't be effected much but in this scenario the engine will use more fuel than it otherwise might.. the slightly rich cylinders will use more fuel and the slightly lean cylinders will use more fuel.

I see some LPG converted vehicles including Elgrands on which the installer seems to have done not too bad a job (comparatively with others I see), fuel trims not too bad etc, but during transient conditions the mixture swing is far different from what it is supposed to be. This can also waste fuel. With some system electronics this condition will exist even on otherwise OK installs because the electronics are not capable of accurately following the petrol fuelling strategy, instead the installer has to guestimate the enrichment/leaning during e.g. tip-in conditions.

Incorrect mixture on LPG at high engine loads seems to feature on a lot of Elgrand LPG conversions that I see. This only applies to 'foot down' type conditions but too rich mixture will waste fuel, have the potential to see off marginal cats sooner than running on petrol and (when really rich) lower bhp. Too lean mixture will waste fuel, lower bhp and could damage engine valves.

Extra injection filtering - This only really applies to Elgrands that haven't had the fuelling recall done... They continue to inject a small amount of petrol during what should be expected to be engine over-run conditions. An LPG install that follows this aspect of the petrol system will inject a small but not well metered (so could be higher than a small amount at times, other times inject nothing) amount of LPG during over-run. The effects are to increase fuel consumption during over-run plus in some cases cause popping (little backfires) in the exhaust during longer times spent in over-run conditions (such as downhill maybe slowly decelerating on a motorway).

If you have to visit the installer for anything it will be both an inconvenience and an additional cost. I have had a few customers who have had minor issues that have returned to me but they have been few and far between, especially considering the very high number of Elgrands I have converted. A 1000 mile check shouldn't be necessary, this is really the installer's get out of jail free card in case there are any initial problems. Annual servicing should be simple and DIYable.
.
 
Last edited:
Magnu said:
You'll probably know this but I'll say it anyway. Payback time is is variable and depends upon
  • conversion cost
  • price difference between LPG and petrol
  • mileage
  • drivers driving style
  • journey types
When I did my calculations the fuel difference was about 80p a litre and an estimate of 6000 miles a year. I estimated it would take me 2 years which nicely coincided with the conversion warranty if the installer does the first annual service check.
Click to expand...
You missed off one vital component of that calculation ... smugness factor .. that's worth about £1000 on it own!!
 
Looking into LPG....Mrs starts her new job shortly which means we get weekends back, in turn more camping/travelling so might be worth it. I've shot @Lpgc a message so I can weigh up the cost Vs payback time.
Lpgc said:
Where did you send me the message?
Click to expand...
On here 👍🏻
 
Deanhempshall said:
Looking into LPG....Mrs starts her new job shortly which means we get weekends back, in turn more camping/travelling so might be worth it. I've shot @Lpgc a message so I can weigh up the cost Vs payback time.

On here 👍🏻
Click to expand...
Seems I nearly missed your PM there mate sorry. I've replied now.

Cheers, Simon
 
delimac said:
Had the fuel gauge recall done and gave it only the second blast along the motorway!
Click to expand...
As part of the recall they also sent me a video showing a 'health check' of my vehicle, tyres, brakes, pads, suspension, bushes, exhaust. Good to get a tour underneath my car and the technician was impressed, no problems and spotless for a 15yr old!!
 
Lpgc said:
I'd also add
  • tank capacity
  • how soon the system switches from petrol to LPG during engine warmup
  • whether or not any 'petrol addition' or 'switch back to petrol at high engine loads' is used,
  • equal fuelling on all cylinders
  • correct mixture swing during transient conditions such as adjusting the throttle
  • correct (suitably rich but not as rich as petrol) mixture during high load open loop fuelling conditions
  • correct extra injection filtering
  • having to visit the installer
Click to expand...

Redmeg said
You missed off one vital component of that calculation ... smugness factor .. that's worth about £1000 on it own!!
Click to expand...
@Redmeg I must admit to feeling smug when my first LPG fuelling was at 54.9 ppl :laughing:
@Lpgc all good points but I went for a simple calculation, mainly because I have no idea how to put them into a spreadsheet. I should have also factored in that during the honeymoon period I have enjoyed giving her some wellie from time to time, it may have knocked off a few weeks from the break even point.
 
@Lpgc - I can’t remember what the header tank is like, if it’s pressurising the system and pushing out put a pipe and tonic bottle on so it sucks it back up. I had an RR with failing head gasket like it for years until power was too low to be wanting to drive it. Doesn’t solve the problem but avoids having to make the top ups. If you think it may be leaking but can’t find it you could put UV dye in it like they do with central heating systems. Fingers crossed it’s not the head.
 
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