Mercedes and LPG

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stewartw · #1 Post by **stewartw** » Thu Mar 05, 2009 10:11 am

Hi

Just got off the phone with Mercedes, and was told that Mercedes don't recommend converting there cars to LPG. As it LPG heats up quicker it will wear the components out faster.

Are they just yanking my leg. As I thought Mercs were better quality then Renault, Ford etc. and these run fine on it.

Cheers guys

I'm going to look at an A150 Elegance SE on an 07.

Your opinions on Conversion for this car would be most helpfull.

Gilbertd · #2 Post by **Gilbertd** » Thu Mar 05, 2009 9:16 pm

I would also add that LPG seems to wear the engine out slower. My Saab currently has 236,000 miles on the clock and running on LPG the oil stays clean. To my way of thinking, clean oil will lubricate better so there will be less wear not more.

Active_Lad · #3 Post by **Active_Lad** » Thu Mar 05, 2009 9:29 pm

I can't claim that sort of mileage, but my Vitara had a service just before the conversion. I was checking the oil level at the weekend and after 7,000 miles, I was surprised how clean it was. Still a golden honey yellow rather than the usual mucky black/brown.

Reminded me of the Fabia TV advert; filling the sump full of Golden Syrup!

junkcatcher · #4 Post by **junkcatcher** » Sat Mar 07, 2009 11:12 am

Active_Lad wrote:I can't claim that sort of mileage, but my Vitara had a service just before the conversion. I was checking the oil level at the weekend and after 7,000 miles, I was surprised how clean it was. Still a golden honey yellow rather than the usual mucky black/brown.

Reminded me of the Fabia TV advert; filling the sump full of Golden Syrup!

More to do with modern fully synthetic oils.
Even running on petrol modern synthetic oils stay very clean, in contrast if you put an old fashioned oil such as GTX Magnatec it will turn black after only a few miles.

There was an experiment running in the US with owners running cars on Mobile "1" 0w/40 fully synthetic without changing the oil but getting samples of the engine oil analysed.
The results I saw seemed to indicate that with filter and partial oil changes where 500ml or so was drained off and fresh oil added every 20,00 miles or so well over 100,000 miles should be possible without oil changes.

As for myself I always use fully synthetic but change my oil twice a year which works out at about 7,000 miles between changes less than half the official Rover interval, the oil is always transparent.. These days I only remove the sump plug and drain the oil fully ever couple of years as a bought one of those pumps that suck the oil up through the dipstick tube (less than 30 pounds from a yacht chandler).

junkcatcher · #5 Post by **junkcatcher** » Sat Mar 07, 2009 11:22 am

Gilbertd wrote:I would also add that LPG seems to wear the engine out slower. My Saab currently has 236,000 miles on the clock and running on LPG the oil stays clean. To my way of thinking, clean oil will lubricate better so there will be less wear not more.

Is it a real SAAB or a GM Saab ---- If it is a GM Saab I am seriously impressed these engines are hypercritical of oil quailty as they are a very prone to serious engine problems related to the lubrication system gumming up.
If I had one I wouldn't dare do over 5,000 miles between changes using a top quality fully synthetic.

billynoband · #6 Post by **billynoband** » Sat Mar 07, 2009 3:19 pm

I tried fully synthetic on my Zafira which burns a bit of oil anyway, about half a litre per 500 miles. It disapeared quicker than a rabbit down a hole. I don't know where it went to but I could not keep up with topping it up. The same stuff was fine in my Renault which did not use any oil. Perhaps it's too thin for cars which burn a bit of oil and it gets blown out.

SAD199 · #7 Post by **SAD199** » Sat Mar 07, 2009 9:02 pm

The GM SAAB junkcatcher refers to is the B205E engine. I know, I've got one

The problem was two fold. 1. The oil breather pipes were badly designed and the engine couldn't breathe properly. This led to the oil being sucked into the the engine and being consumed as well as overheating. 2. The cat is up against the bottom of the engine and it heated the small amount of oil too high. This unfortunate combination meant that oil sludge was created, blocking the strainer at the bottom of the engine leading to oil starvation and the inevitable consequence. SAAB originally specified semi-synthetic and a 12000 mile change which didn't help. The good news is that there is a redesigned breather kit available, about £30 and now fully synthetic is recommended. I change mine every 6000 miles and it's fine. Others recommend the sump being dropped to ensure the strainer is clear as a precaution.

Gilbertd · #8 Post by **Gilbertd** » Sun Mar 08, 2009 1:32 pm

I was about to point out the same thing. My car is a GM900 from '96 which didn't suffer the problem, that was the 9-3 and 9-5 from '98 onwards. It affected something like 800,000 cars and Saab gave an 8 year warranty on any affected cars (but only if they had a full Saab service history). I had a 9-5 that had been given a brand new engine and turbo assembly under warranty when it had done 112,000 miles and was 7 years 11 months old.

Although the GM 900 was based on the Vectra floorpan, it still had enough Saab bits in it to last. Incidentally, it isn't only down to the oil used. I agree that something like Mobil 1 will stay clean but I use cheapo semi-synthetic from my local motor factors. That stays clean in my Saab on gas but doesn't in my wifes Vauxhall Tigra on petrol.

Active_Lad · #9 Post by **Active_Lad** » Sun Mar 08, 2009 10:12 pm

junkcatcher wrote:More to do with modern fully synthetic oils.

I don't think you can claim that necessarily when doing a like for like comparison pre and post conversion. The oil is certainly cleaner post conversion.

Corriepups · #10 Post by **Corriepups** » Mon Mar 09, 2009 11:49 am

Whoever told you that Mercedes dont approve of LPG should refer to WIS(merc electronic workshop info) AH00.10-P-1000-02A. They dont have a problem with it but do warn of possible valve seat wear on certain engines.

nypd · #11 Post by **nypd** » Mon Mar 09, 2009 8:46 pm

Hi Guys
I have a 230cse 1984 with a Landi system fitted.
I would like to maintain it myself - do you have any fitting details that will explain the wiring and component details
the engine is early injection and the gas is delivered via a mixer in the inlet manifold
regards
nypd

nypd · #12 Post by **nypd** » Thu Mar 12, 2009 10:05 pm

Hi Guys
With the open loop mixer system on my 1984 230cse using early type fuel injection how is the petrol cut off when switching to lpg?
would it be a simple fuel pump cut off and fuel line solenoid or are other switching systems needed?
regards
Hans

stewartw · #13 Post by **stewartw** » Wed May 06, 2009 8:38 pm

Well finally bought the car and had the conversion done. though i'm experiencing some problems, i've left another thread.

Sir Henry · #14 Post by **Sir Henry** » Thu May 14, 2009 1:24 pm

Active_Lad wrote:
junkcatcher wrote:More to do with modern fully synthetic oils.
I don't think you can claim that necessarily when doing a like for like comparison pre and post conversion. The oil is certainly cleaner post conversion.

Re oil colour: The Old Girl - a 1976 Rolls Royce Silver Shadow with 92k on the clock - goes from oil change to oil change with no change in oil colour despite the fact that I only use bog-standard 20w 50 oil in her (original factory specs). This does not change whether I run her on petrol or gas.
I put this down to the fact that I flushed her out twice at the first oil change (as I do for all the used cars I buy), flush at every subsequent oil change and dump the oil & filter every 3,000 miles. FYI she takes 2 gallons per change, not including flushing, and requires approx. 1 litre of oil as a top-up at about half that distance.
Fortunately I have no worries about valve seat recession as she was fitted with hardened valve seat inserts from new. Also, as a "belt and braces" move, I added a Flashlube system to drip UCL into the air path just downstream of each carb

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